JP5752009B2 - Service cooperation apparatus, service cooperation method, and program - Google Patents

Description

  The present invention relates to a service cooperation apparatus that links two or more services.

As a method of creating a new function by using data and functions of a plurality of systems, each system data and function is disclosed as a service such as a Web service, such as SOA (Service Oriented Architecture). Then, there is a method of sequentially starting published services.
At this time, in order to link the sequentially activated services, a process is performed in which the output of the first activated service is used as the input of the next activated service.

In middleware that performs service cooperation, such as a conventional ESB (Enterprise Service Bus), service activation is controlled by a message flow, and data input and output by the service is carried by the message (for example, non-patent literature) 1 page 15 “4.4 Normalized Message Exchange”).
When linking services, the ESB stores the output data of the previously activated service in a message.
Next, the ESB extracts data from the message and uses it as an input to a service to be activated later.
The ESB performs service cooperation by repeating this.

In addition, a service call is often performed by communication, and when communication is regarded as a data stream, a method of linking data streams has also been proposed (for example, Patent Document 1).
In Patent Document 1, data that can be acquired from a certain data stream is stored in a pipe (described as a queue in Patent Document 1), and the data stored in the pipe is regarded as a table in a relational database, and data is extracted therefrom ( SELECT).
The extracted data is stored in a virtual table while character code conversion or combination with another table is performed.
Service linkage is performed by writing the data stored in this virtual table to a stream that is input to another service.

JP 2011-13989 A

Java Business Integration 1.0 (Java is a registered trademark) <http: // jcp. org / aboutJava / communityprocess / final / jsr208 / index. html>

  The conventional ESB described in Non-Patent Document 1 has the following problems when a large amount of data is used for input / output with a service.

1) There is a problem that processing for storing and retrieving service input / output data becomes a bottleneck.
In the method of storing data in a message, the next service cannot be started unless the process of storing the data output from a certain service or the process of retrieving the stored data is completed.
Therefore, when there is a large amount of data, the process of storing or retrieving data in a message may be a bottleneck in the process of linking multiple services.
In particular, when a service is executed by an external computer, the computer is in a waiting state during the process of storing data in a message.

2) Since messages are actually stored in memory, storing data on messages means that the output of the service (the entire message) is stored in memory at once, which consumes a large amount of memory. there's a possibility that.

On the other hand, when the method of writing the data acquired from the data stream to the data stream of the cooperation destination at any time like the stream integration described in Patent Document 1, the two of Non-Patent Document 1 are used. The problem is solved.
However, even in this case, there are the following problems.

The method of simply storing data acquired from one data stream in a pipe has a problem that it cannot be written in a plurality of data streams.
In a normal pipe, the read data is discarded at the time of reading, and thus service cooperation that uses the same data for a plurality of services cannot be realized.
Although it is conceivable that data is not discarded when data is read from the pipe, in such a case, it is necessary to control the timing at which the data stored in the pipe is discarded.

  The main object of the present invention is to solve the above-mentioned problems, and when performing service cooperation using a pipe, the main object is to make it possible to use the same data for a plurality of services. Objective.

The service cooperation apparatus according to the present invention is:
A service cooperation device for linking two or more services implemented by any service application,
A plurality of service connection units that correspond to any one of a plurality of service applications and that transmit and receive variable values with the corresponding service application at the time of service linkage,
Before starting service linkage, analyze the linkage scenario showing the service linkage procedure, and for each variable used for service linkage, set the variable value during service linkage from the multiple service connections. A definition analysis unit that specifies an output service connection unit to output and an input service connection unit to input a variable value, and the input service connection unit and the input service connection unit that generate the input / output definition information indicated for each variable; ,
A storage unit that stores the input / output definition information generated by the definition analysis unit before service cooperation starts;
When linking services, based on the input / output definition information, a pipe that holds the variable value, a pipe writing means that inputs the variable value from the output service connection unit and writes the variable value to the pipe, and an input service that reads the variable value from the pipe A pipe reading unit for outputting to the connection unit, and a pipe management unit for generating each variable,
Each service connection
At the time of service linkage, the variable value received from the corresponding service application is output to the pipe writing means corresponding to the variable value, the variable value input from the pipe reading means is transmitted to the corresponding service application,
The definition analysis unit
As a result of analyzing the cooperation scenario, when one output service connection unit and two or more input service connection units are specified for any variable,
A duplicate write process that duplicates the variable value input from the output service connection and writes it in parallel to two or more pipes to two or more input service connections;
Read variable value from one pipe, duplicate the read variable value, output the variable value to the input service connection part of the pipe and write to the pipe to the other input service connection part. Specify
Generate I / O definition information that indicates either replication write processing or read replication processing for the variable,
The pipe management unit
One pipe writing means is generated for a variable in which either of the replication writing process and the reading replication process is indicated, and a pipe and a pipe reading means are generated for each input service connection unit.
For variables for which duplicate write processing is indicated, the created pipe write means executes duplicate write processing,
For the variable for which the read duplication processing is indicated, the generated pipe read means is caused to execute the read duplication processing.

  According to the present invention, it is possible to perform a replication write process in which a variable value is duplicated and written in parallel to two or more pipes, and a read replication process in which a variable value read from one pipe is duplicated and written to another pipe. The same variable value can be used to execute multiple services.

FIG. 3 is a diagram illustrating an example of a system configuration according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of a service cooperation apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a configuration example of a pipe writing unit and a pipe reading unit according to the first embodiment. FIG. 3 is a diagram illustrating a scenario definition example according to the first embodiment. FIG. 5 is a diagram showing an example of interface definition according to the first embodiment. FIG. 3 is a diagram illustrating an example of an access route according to the first embodiment. FIG. 6 is a diagram showing a pipe allocation definition example according to the first embodiment. FIG. 4 is a diagram showing a process flow of a scenario definition example according to the first embodiment. FIG. 3 is an analysis processing flowchart according to the first embodiment. FIG. 3 is a process execution flowchart according to the first embodiment. FIG. 4 is a process flow diagram of a service connection unit according to the first embodiment. The figure which shows the processing example of the pipe writing means and pipe reading means which concern on Embodiment 1. FIG. The figure which shows the processing example of the pipe writing means and pipe reading means which concern on Embodiment 1. FIG. FIG. 4 is a diagram illustrating a processing example of a pipe writing unit according to the first embodiment. FIG. 4 is a diagram illustrating a configuration example of a service cooperation apparatus according to a second embodiment. FIG. 6 is a process execution flowchart according to the second embodiment. FIG. 10 is a diagram illustrating a configuration example of a pipe writing unit and a pipe reading unit according to the third embodiment. FIG. 10 is a diagram illustrating an example of interface definition according to the third embodiment. FIG. 10 is a diagram showing an example of pipe allocation definition according to the third embodiment. FIG. 10 is a diagram illustrating a configuration example of a service cooperation apparatus according to a fourth embodiment. FIG. 10 is a flowchart showing a processing example of a service connection unit according to the fourth embodiment. The figure which shows the hardware structural example of the service cooperation apparatus which concerns on Embodiment 1-6.

Embodiment 1 FIG.
In this embodiment, even when a large amount of data is used for input / output of a service, a configuration is described in which the same data can be used for multiple services while executing the service at any time using a pipe. To do.
The pipe in this specification is a concept similar to the pipe in UNIX (registered trademark), and is a means for holding a variable value in order to transmit and receive the variable value between processes (or threads).

In the present embodiment, a configuration is also described in which, when services are linked using a pipe, data that is not used in subsequent service processing is not written to the pipe to eliminate waste.
For example, when the output of the data stream is composed of a plurality of items (columns in the table) as in Patent Document 1, data that is not used in later processing may be stored in the pipe, which is useless. .
In the present embodiment, data that is not used in such subsequent processing is not written to the pipe.

  FIG. 1 is a diagram illustrating a system configuration example according to the first embodiment.

In FIG. 1, a service cooperation apparatus 1000 is an apparatus for linking a plurality of services.
The service cooperation apparatus 1000 is often implemented using a program on a computer such as a PC (Personal Computer) or a server apparatus (for example, ESB), but may be a dedicated apparatus.

  The service cooperation apparatus 1000 is connected to a service utilization system 4000 that uses a service, receives a service provision request for requesting provision of a service from the service utilization system 4000, and coordinates a plurality of services based on the service provision request.

Further, the service cooperation apparatus 1000 communicates with service application A2001 to service application D2004, which are application programs for executing services, and cooperates with a plurality of services.
A service executed by the service application A2001 is called service A, a service executed by the service application B2002 is called service B, a service executed by the service application C2003 is called service C, and a service executed by the service application D2004 is called service D.
Service A to service D are services provided to the service use system 4000.
Note that service application A2001 to service application D2004 are each executed by a computer.
That is, the service cooperation apparatus 1000 physically communicates with a computer that implements the service application A2001 to the service application D2004 to cooperate with a plurality of services. However, for convenience, the service cooperation apparatus 1000 is used in this specification. Is described as communicating with service application A2001 to service application D2004.

The service cooperation apparatus 1000 transmits a request data stream to the service application A2001 to the service application D2004, and receives a response data stream that is a response to the request data stream from the service application A2001 to the service application D2004.
In service cooperation, the service cooperation apparatus 1000 may include a variable value included in a response data stream from a certain service application in a request data stream to another service application.
In this case, the service cooperation apparatus 1000 converts the variable value included in the response data stream from one service application (for example, service application A2001) into two or more other service applications (for example, service application B2002 and service application C2003). ) May be included in the request data stream.

  FIG. 2 shows an internal configuration example of the service cooperation apparatus 1000 according to the present embodiment.

  In FIG. 2, the definition analysis unit 1001 has a function of analyzing a scenario definition 1101 and an interface definition 1102 and generating a pipe allocation definition 1103.

The scenario definition 1101 is information defining the order in which the service connection unit A 1008 to the service connection unit D 1011 are activated. FIG. 4 is an example of the scenario definition 1101.
FIG. 8 is a diagram showing the processing flow of this scenario example.
In the example of FIG. 4, after executing the service connection unit A1008, it is divided into two processes executed in parallel.
The first process is a process for executing the service connection unit B1009, and the other process is a process for executing the service connection unit C1010 and the service connection unit D1011.
As will be described later, the service connection unit A 1008 to the service connection unit D 1011 are functions for communicating with the service application A 2001 to the service application D 2004.

The interface definition 1102 defines the input / output of the service connection unit A 1008 to the service connection unit D 1011.
The interface definition 1102 describes a variable acquired by the service connection unit and a service connection unit that uses the variable in order to exchange data between the service connection units.
FIG. 5 is an example of the interface definition 1102.
In the example of FIG. 5, it is shown that the service connection unit B 1009 (denoted as nb in FIG. 5) inputs the variable value of the variable p1 output from the service connection unit A 1008 (denoted as na in FIG. 5). It is shown that the service connection unit B 1009 (nb) and the service connection unit C 1010 (denoted as nc in FIG. 5) input the variable value of the variable p2 output by the service connection unit A 1008 (na).
In addition, it is shown that the service connection unit C1010 (nc) and the service connection unit D1011 (denoted as nd in FIG. 5) input the variable value of the variable p3 output by the service connection unit A1008 (na). It is shown that the variable value of the variable p4 output by the connection unit B1009 (nb) is not input by any service connection unit.

  In the scenario definition 1101 and the interface definition 1102, as shown in FIGS. 4, 5, and 8, service cooperation procedures are shown. The scenario definition 1101 and the interface definition 1102 correspond to examples of cooperation scenarios.

The pipe allocation definition 1103 defines pipe processing applied in each service connection unit.
The pipe allocation definition 1103 is information shown in FIG. 7, for example.

  Although details of FIG. 7 will be described later, the pipe allocation definition 1103 outputs a variable value for each variable (p1, p2, p3, and p4 in the example of FIG. 7) when the service is linked. Output service connection units (in the example of FIG. 7, na (p1 to p3), nb (p4)) and input service connection units for inputting variable values (in the example of FIG. 7, nb (p1), nb and nc ( p2), nc, and nd (p3)), and the pipe allocation definition 1103 corresponds to an example of input / output definition information.

The pipe management unit 1002 has a function of creating a pipe 1006 necessary for the operation of the service connection unit and allocating the pipe writing unit 1004 and the pipe reading unit 1005 based on the pipe allocation definition 1103.
More specifically, the pipe management unit 1002 activates threads (processes) of the pipe writing unit 1004 and the pipe reading unit 1005, and allocates a predetermined area of the memory to the pipe 1006.

The service disclosure unit 1003 receives a processing request from the outside to the service cooperation apparatus 1000 so that the service cooperation apparatus 1000 can use the newly created function by linking the service application A2001 to the service application D2004 from the outside of the apparatus. It is a function.
For example, it is disclosed in the form of a Web service that calls a function using HTTP (Hypertext Transfer Protocol).
The service utilization system 4000 can call a service published by the service disclosure unit 1003.
Upon receiving a processing request (service provision request) from the service utilization system 4000, the service disclosure unit 1003 transmits an ESB message to the scenario control unit 1007.
The service disclosure unit 1003 corresponds to an example of a service provision request reception unit.

  The scenario control unit 1007 has a function of transmitting an ESB message to the service connection unit A 1008 to the service connection unit D 1011 based on the scenario definition 1101.

Service connection unit A 1008 to service connection unit D 1011 correspond to service application A 2001 to service application D 2004, and perform service call processing in the corresponding service application.
The service connection unit A 1008 to the service connection unit D 1011 operate by receiving an ESB message from the scenario control unit 1007.
The service connection unit A 1008 to the service connection unit D 1011 store a reference to the pipe reading unit 1005 for acquiring data to be input to the service application from the pipe management unit 1002 and an output from the service application before calling the service application. To obtain a reference to the pipe writing means 1004 for
The service connection unit A 1008 to the service connection unit D 1011 transmit / receive a request data stream and a response data stream including the variable value to / from the corresponding service application while inputting / outputting the variable value to / from the pipe 1006.
In FIG. 1, four service connection units and four services are provided as an example. However, in practice, one or more services are sufficient, and the number is not limited to four.

  The request data stream A 3001 to the request data stream D 3004 and the response data stream A 3101 to the response data stream D 3104 represent data input to the service application and data output from the service application, respectively.

Here, the service provided by the service application is a function that can be used by communication such as Web service or FTP (File Transfer Protocol), or a function on a computer such as a file system, and a data stream is a service connection unit. Is created when using the service.
For example, in the case of a Web service, the service connection unit establishes a TCP (Transmission Control Protocol) connection with the service application, transmits an HTTP request, and acquires an HTTP response from the service application.
These HTTP requests and HTTP responses correspond to a request data stream and a response data stream, respectively.
For example, consider a case where the service application is a file system and the operation executed by the service application is to create a file and write data sequentially.
At this time, the service connection unit opens the file by API (Application Programming Interface) such as fopen, and sequentially passes the data to the file system.
At this time, the data to be written to the file corresponds to the request data stream.
In this case, since no data is acquired from the file, there is no data in the response data stream.

The pipe 1006 is a container (communication path) of data (variable value) used to pass data (variable value) acquired by the service connecting unit to another service connecting unit.
The pipe writing unit 1004 has a function of performing processing for writing the data (variable value) acquired by the service connection unit into the pipe 1006, and the pipe reading unit 1005 stores the data (variable value) written in the pipe. This function reads data (variable values) from a pipe for use in a service connection unit.

  FIG. 3 is a diagram showing a detailed configuration of the pipe writing unit 1004, the pipe 1006, and the pipe reading unit 1005.

The pipe writing means 1004 has a write data copy function 10041 and a read discard function 10042.
The write data copy function 10041 copies the data (variable value) and writes the same data (variable value) to the plurality of pipes 1006 so that the same data (variable value) can be used by the plurality of pipe reading means 1005. It is a function.
The discarding function 10042 is a function for discarding data (variable values) that are not used by the pipe reading unit 1005 without writing them to the pipe 1006.
The pipe reading unit 1005 has a read data copy function 10051.
The read data copy function 10051 is a function for copying the read data and writing it to the pipe 1006 so that the data once read can be used again by the pipe reading means 1005.

Pipe writing means 1004, pipe 1006, and pipe reading means 1005 are generated for each variable value access path for each variable.
For example, in reference numerals 7011 to 7013 of the pipe allocation definition 1103 in FIG. 7, the access path from the service connection unit A 1008 (na) to the service connection unit B 1009 (nb) and the service connection unit A 1008 (na) for the variable value of the variable p2. ) To the service connection unit C1010 (nc).
When the description of reference numerals 7011 to 7013 is executed, the pipe writing unit 1004a generates the pipe writing unit 1004a that inputs the variable value of the variable p2 from the service connection unit A1008 (na) and writes the variable value to the pipe 1006. Is done.
Also, as the pipe 1006, a pipe 1006b for transmitting a variable value to the service connection unit B 1009 (nb) and a pipe 1006c for transmitting a variable value to the service connection unit C1010 (nc) are generated.
Also, as pipe reading means 1005, pipe reading means 1005b that reads a variable value from the pipe 1006b and outputs the variable value to the service connection unit B1009 (nb), and reads a variable value from the pipe 1006c and service connection unit C1010 (nc) The pipe reading means 1005c for outputting the variable value is generated.
Hereinafter, “a” to “d” appended to the end of the pipe writing unit 1004, the pipe 1006, and the pipe reading unit 1005 mean the service connection unit A 1008 to the service connection unit D1011.

  The storage unit 1020 stores a scenario definition 1101, an interface definition 1102, and a pipe allocation definition 1103.

Next, the operation will be described.
The operation of the first embodiment is divided into two stages of processing.
The first process is an analysis process for analyzing the interface definition 1102 and the scenario definition 1101 to create a pipe allocation definition 1103.
The second process is an execution process for executing a service in accordance with a request from the service utilization system 4000 while using the pipe allocation definition 1103.

  The analysis process will be described with reference to FIG.

Analysis start S0001 represents the start of analysis processing.
In the variable access conflict determination S0002, the definition analysis unit 1001 analyzes the interface definition 1102 and the scenario definition 1101, and performs a conflict determination regarding access to a variable.
For example, there is a conflict when the same variable is updated in each of the processes divided by fork.
If there is a conflict, the process proceeds to analysis failure S0006 as an analysis failure.
If there is no conflict, the process proceeds to variable access path creation S0003.
In the variable access path output S0003, the definition analysis unit 1001 analyzes where the value is updated for each variable and uses the value, and outputs the access path as shown in FIG.

The access route in FIG. 6 is generated based on the scenario definition 1101 in FIG. 4 and the interface definition 1102 in FIG.
In the example of FIG. 6, the variable value of the variable p1 is only output from the service connection unit A1008 (indicated as na in FIG. 6) and input to the service connection unit B1009 (indicated in FIG. 6 as nb). There is one path (access route).
On the other hand, the variable value of the variable p2 is output from the service connection unit A1008 (na) and input to the service connection unit B1009 (nb) and the service connection unit C1010 (denoted as nc in FIG. 6). ) Is two.
Similarly, the variable value of the variable p3 is output from the service connection unit A1008 (na) and input to the service connection unit C1010 (nc) and the service connection unit D1011 (denoted as nd in FIG. 6). There are two routes.
In addition, the variable value of the variable p4 is output from the service connection unit B1009 (nb), but is not input to any service connection unit, so there is one path (access route).

In the next pipe allocation definition output S0004, a pipe allocation definition 1103 as shown in FIG. 7 is generated based on the access path, the generated pipe allocation definition 1103 is output to the storage unit 1020, and the pipe allocation definition is output to the storage unit 1020. 1103 is stored.
The pipe allocation definition 1103 is a definition of how and in which node a pipe for reading and writing variables is used.
The analysis ends S0005 by the output of the pipe allocation definition 1103.

  The analysis processing illustrated in FIG. 9 is executed before the service disclosure unit 1003 is called from the service use system 4000, such as when the service cooperation apparatus 1000 is activated.

  Next, the execution process will be described with reference to FIG.

START S1001 represents the start of processing.
In the request reception S1002, the service disclosure unit 1003 receives a service provision request from the service use system 4000.
When the service disclosure unit 1003 receives the service provision request, the service disclosure unit 1003 makes a service execution request to the scenario control unit 1007.

In the scenario control S1003, the scenario control unit 1007 that has received the service execution request calls the service connection unit corresponding to the service to be executed based on the scenario definition 1101.
In service processing S1004, the called service connection unit communicates with an external service application to execute the service. Details of the service processing S1004 will be described later.
When a response is returned from the service connection unit to the scenario control unit 1007, it is determined in scenario end determination S1005 whether the scenario control unit 1007 has executed all the services defined in the scenario definition 1101.
If there are still services that have not been executed, the process returns to the scenario control S1003 to execute the services.
When all the services are being executed, the process waits until all the services are completed in the next service completion waiting S1006.
After the service is completed, the service disclosure unit 1003 returns an execution result response to the service use system 4000 in request response S1007, and the process proceeds to END S1008, which is the end of the process.
Note that when the service use system 4000 issues a service provision request, an asynchronous operation can be performed. In this case, the request response S1007 is not executed, and the processing result is not notified to the service use system 4000.

  Before describing the processing flow of the service processing S1004, the operations of the pipe writing unit 1004, the pipe 1006, and the pipe reading unit 1005 used in the service processing will be described.

12 to 14 are diagrams showing processing of the pipe writing unit 1004, the pipe 1006, and the pipe reading unit 1005.
Normally, variable values written to pipe 1006 are discarded by being read.
However, depending on the service execution order, the variable value written in the pipe 1006 may be used by a plurality of service connection units.
Therefore, when it is necessary to read the same variable value by a plurality of service connection units, the pipe writing unit 1004 and the pipe reading unit 1005 perform variable value duplication processing so that the same variable value can be used at a plurality of locations.
There are two ways to read the same variable value at multiple locations. One is when the variable value is used simultaneously in multiple service connections by fork, and the other is when the variable value is read. This is a case where the variable value is used again at a location after the location.

For the former, as shown in FIG. 12, the write data copy function 10041 in the pipe writing means 1004 writes the same variable value to a plurality of pipes 1006 to perform variable duplication processing (duplicate write processing).
For the latter, as shown in FIG. 13, the read data copy function 10051 in the pipe reading unit 1005 performs the variable value duplication processing by writing the read variable value to another pipe 1006 again (read duplication). processing).

FIG. 12 shows a state where the description of reference numerals 7011 to 7013 of the pipe allocation definition 1103 in FIG. 7 is being executed.
That is, in the pipe allocation definition 1103 in FIG. 7, reference numerals 7011 to 7013 describe the replication write process for the variable p2.
When the description of reference numerals 7011 to 7013 is executed, the pipe writing means 1004a corresponding to the service connection unit A1008 (na) inputs the variable value of the variable p2 from the service connection unit A1008 (na), and the variable value of the variable p2 And writes the same two variable values into the pipe 1006b to the service connection B 1009 (nb) and the pipe 1006c to the service connection C 1010 (nc).
Further, the pipe reading unit 1005b corresponding to the service connection unit B1009 (nb) reads the variable value of the variable p2 from the pipe 1006b and outputs it to the service connection unit B1009 (nb), corresponding to the service connection unit C1010 (nc). The pipe reading means 1005c reads the variable value of the variable p2 from the pipe 1006c and outputs it to the service connection unit C1010 (nc).

FIG. 13 shows a state where the description of reference numerals 7021 to 7023 of the pipe allocation definition 1103 in FIG. 7 is being executed.
That is, in the pipe allocation definition 1103 in FIG. 7, reference numerals 7021 to 7023 describe the read replication process for the variable p3.
When the description of reference numerals 7021 to 7023 is executed, the pipe writing means 1004a corresponding to the service connection unit A1008 (na) inputs the variable value of the variable p3 from the service connection unit A1008 (na), and the input variable value is Write to the pipe 1006c to the service connection C1010 (nc).
Further, the pipe reading unit 1005c corresponding to the service connection unit C1010 (nc) reads the variable value of the variable p3 from the pipe 1006c, duplicates the read variable value of the variable p3, and transfers one variable value to the service connection unit C1010 (nc). ) And the other variable value is written to the pipe 1006d to the service connection unit D1011 (nd), and the pipe reading unit 1005d corresponding to the service connection unit D1011 (nd) reads the variable value of the variable p3 from the pipe 1006d. To the service connection unit D1011 (nd).

If the variable value acquired by the service connection unit is not used in the subsequent processing, it is useless to write the variable value to the pipe 1006.
In such a case, as shown in FIG. 14, the discarding function 10042 in the pipe writing unit 1004 discards the variable value without writing the variable value to the pipe 1006 (deleting process).

FIG. 14 shows a state in which the description of reference numeral 7031 of the pipe allocation definition 1103 in FIG. 7 is being executed.
That is, in the pipe allocation definition 1103 in FIG. 7, reference numeral 7031 describes a deletion process for the variable 4.
When the description of reference numeral 7031 is executed, the pipe writing unit 1004b corresponding to the service connection unit B1009 (nb) inputs the variable value of the variable p4 from the service connection unit B1009 (nb). Discard the value.

  In this way, the pipe management unit 1002 controls what processing is performed by the pipe writing unit 1004 and the pipe reading unit 1005 according to the pipe allocation definition 1103.

  Next, service processing in the execution processing will be described with reference to FIG.

  S2001 represents the start of the service process, and the process is started when the scenario control unit 1007 calls the service connection unit.

In S2002, obtaining a reference to the pipe writing unit and the pipe reading unit, the called service connection unit requests the pipe management unit 1002 to refer to the pipe reading unit 1005 and the pipe writing unit 1004.
Upon receiving the request, the pipe management unit 1002 refers to the pipe reading unit 1005 that has already been created for the pipe reading unit 1005 based on the pipe allocation definition 1103, and pipe writing unit 1004, pipe for the pipe writing unit 1004. A new set of reading means 1005 is created, and the reference of the pipe writing means 1004 therein is returned to the service connection unit.
That is, when the service connection unit outputs a variable value, the service connection unit requests the pipe management unit 1002 to refer to the pipe writing unit 1004, and the pipe management unit 1002 performs pipe writing based on the pipe allocation definition 1103. A means 1004 and a pipe reading means 1005 are generated, and a reference (for example, a pointer) to the generated pipe writing means 1004 is returned to the service connection unit.
For example, when the service connection unit A 1008 (na) outputs the variable value of the variable p2, the pipe management unit 1002 is based on the description of reference numerals 7011 to 7013 of the pipe allocation definition 1103 in FIG. , A pipe writing unit 1004a corresponding to the service connection unit A1008 (na), a pipe reading unit 1005b corresponding to the service connection unit B1009 (nb), and a pipe reading unit 1005c corresponding to the service connection unit C1010 (nc). Create a new one and notify the service connection unit A 1008 (na) of the reference to the pipe writing means 1004a.
The pipes 1006b and 1006c may be created by the pipe management unit 1002 at this time, or may be created when the pipe writing unit 1004a actually writes a variable value to the pipe.
When the pipe 1006 is generated, the pipe management unit 1002 allocates a predetermined memory area to the pipe 1006 to be generated.
When the service connection unit inputs a variable value, for example, when the service connection unit B 1009 (nb) inputs a variable value of the variable p2, the service connection unit B 1009 (nb) reads the pipe to the pipe management unit 1002. The pipe management unit 1002 requests the reference to the unit 1005, and notifies the service connection unit B 1009 (nb) of the reference to the pipe reading unit 1005b that has already been created.

In request data stream creation S2003, the service connection unit that has acquired the reference to the pipe reading unit 1005 creates a request data stream for using the service.
That is, the service connection unit generates a part other than the variable value among the constituent elements of the request data stream.

In allocation of request data stream to pipe reading means S2004, the service connection unit activates a thread (or process) and acquires data (variable value) used for the request from the pipe reading means 1005 for the created thread. Then, assign a process to write the request to the request data stream.
Then, the service connection unit transmits the request data stream in which the variable value is written to the corresponding service application.

In response data creation S2005, a response data stream for obtaining a response from the service application is created.
The response data stream may be generated by a service connection unit or a service application depending on a communication protocol.

In step S2006, the service connection unit starts a thread (or process), acquires response data (variable value) from the response data stream, and writes the response data stream to the pipe writing unit. A process for writing response data (variable value) is assigned to the means 1004.
Here, the pipe writing unit 1004 serving as the writing destination is the pipe writing unit 1004 that has acquired the reference in S2002.

  In END S2007, the service connection unit returns control to the scenario control unit 1007.

As described above, according to the first embodiment, the pipe management unit 1002 controls the deletion of data by controlling the copying of variables in the pipe writing unit 1004 and the pipe reading unit 1005 according to the pipe allocation definition 1103. The same data can be used by multiple services.
In addition, it is possible to prevent unnecessary data from being written to the pipe.
In addition, when a type of service to be executed externally is added, it is necessary to create a new service connection unit according to the added service. However, data copy processing is performed using the pipe writing unit 1004 and the pipe. Since the reading means 1005 is used, there is no need to recreate the copy processing portion.
Furthermore, by providing the definition analysis unit 1001 for generating the pipe allocation definition 1103, it is not necessary for the designer to directly create the pipe allocation definition 1103, and the time and effort of the designer can be reduced.

In the present embodiment, a service cooperation apparatus having the following functions has been described.
Before the service linkage device uses the service disclosure unit to publish a service, it analyzes the scenario definition in which the service I / F definition and the execution order of the service are written, and determines the pipes required for the execution of each service. Definition analysis unit that creates a pipe allocation definition for
Pipe management unit for creating pipe writing means, pipes, pipe reading means according to the pipe allocation definition,
A service connection unit that executes a service using a pipe writing unit, a pipe, and a pipe reading unit.

Embodiment 2. FIG.
FIG. 15 is a diagram illustrating an internal configuration example of the service cooperation apparatus 1000 according to the second embodiment.
In the second embodiment, a definition update unit 1012 is provided in addition to the first embodiment.
The definition update unit 1012 is a function for re-creating the pipe allocation definition 1103 by calling the definition analysis unit 1001, and is called from the service disclosure unit 1003 when the service disclosure unit 1003 is called from the service usage system 4000. The

  FIG. 16 is a flowchart illustrating an operation example of the second embodiment.

The difference from FIG. 10 which is the process flow of the first embodiment is that an analysis process S3003 is added after the request reception S3002.
In the analysis process S3003, the definition update unit 1012 calls the definition analysis unit 1001 to update the pipe allocation definition 1103 as described above.
That is, in this embodiment, every time the service disclosure unit 1003 receives a service provision request, the definition analysis unit 1001 performs the scenario definition 1101 and the scenario definition 1101 before the service cooperation performed based on the service provision request starts. The interface definition 1102 is analyzed, and the pipe allocation definition 1103 is updated with respect to variables used for service cooperation performed based on the service provision request.

  As described above, in the second embodiment, the definition update function is provided so that the pipe allocation definition 1103 can be updated during the execution of the process. Therefore, the scenario definition 1101 is updated while the service linkage apparatus 1000 is in operation. In this case, pipes can be assigned correctly.

As described above, in the present embodiment, in addition to the configuration of the first embodiment,
Described a service linkage device that has a definition update unit that updates the pipe allocation definition by executing the definition analysis unit when a service published by the service disclosure unit is executed.

Embodiment 3 FIG.
In the third embodiment, in addition to the first embodiment, a message writing function is provided in the pipe writing means 1004, and a message reading function is provided in the pipe reading means 1005.

FIG. 17 is a diagram illustrating a detailed configuration of the pipe writing unit 1004 and the pipe reading unit 1005 according to the third embodiment.
The message 1013 is a message (ESB message) for controlling the activation of the service in the conventional technology (Non-patent Document 1).
The message writing function 10043 writes data in the data area in the message 1013 instead of the pipe 1006.
The message reading function 10052 reads data from the message data area.

  As described above, in the third embodiment, when the user creates the interface definition 1102 as indicated by reference numeral 1801 in FIG. 18, a pipe is not used for a predetermined parameter (p1 in FIG. 18). As a result of the definition analysis processing, message writing (reference numeral 1901) and message reading (reference numeral 1902) are designated in the pipe writing means 1004 and the pipe reading means 1005 as shown in FIG.

As described above, in the third embodiment, by providing the message writing function and the message reading function, it is possible to carry data between services using the data area of the message.
If the data required to link services is small, the advantage of not using pipes to store data in memory is small and the disadvantage of creating pipes is large, but this can be avoided. .

As described above, in the present embodiment, in addition to the configuration of the first embodiment,
We have described a service linkage device that has a message write function and a message read function that allow data to be stored in messages.

Embodiment 4 FIG.
In the fourth embodiment, a response data size determination function is provided in addition to the third embodiment.

FIG. 20 shows an internal configuration example of the service cooperation apparatus 1000 according to the fourth embodiment.
The difference from the third embodiment is that a response data size determination function A10081 to a response data size determination function D10111 are provided.

In the fourth embodiment, when the response data size can be confirmed before the response data is acquired, the data size is acquired, and the response data size determination function uses a pipe to carry the data or a message. It is determined whether to use and a pipe is created according to the determination result, and whether the message writing function 10043 or the message reading function 10052 is used by the pipe writing unit 1004 or the pipe reading unit 1005 is controlled.
Examples of the data size that can be acquired before data acquisition include the case where the data size is written in the header of the communication protocol for using the service, or the use of fsize () in a service that acquires a file. The file size may be acquired in advance.

  FIG. 21 shows a processing flow of service processing in the fourth embodiment.

The differences in the service processing of the first embodiment are the processing contents of the acquisition of reference S4002 to the pipe writing means and the pipe reading means, and the processing after the response data size acquisition availability determination S4006.
In step S4002, the pipe management unit 1002 only creates the pipe writing unit 1004 and the pipe reading unit 1005, and activates the write data copy function 10041 and creates the pipe 1006. Not performed.
The validation of the write data copy function 10041 and the creation of the pipe 1006 are performed after the response data size acquisition possibility determination S4006.
In response data size acquisition possibility determination S4006, the response data size determination function determines whether or not the response data size can be acquired before acquiring response data of the service being executed.
If the data size cannot be acquired, in pipe creation S4007, the pipe management unit 1002 creates a data storage pipe 1006, and validates the write data copy function 10040 and the like according to the pipe allocation definition 1103.
When it is determined in the response data size acquisition possibility determination step S4006 that the data size can be acquired, the response data size determination function acquires the response data size in the response data size threshold determination step S4008 and performs threshold determination.
If the data size is greater than or equal to the threshold value, in pipe creation S4010, the pipe management unit 1002 creates a data storage pipe 1006, and validates the write data copy function 10040 and the like according to the pipe allocation definition 1103.
If it is less than the threshold, the pipe management unit 1002 performs a preparation process for storing the response data in the message in S4009 for enabling the message writing function 10043 and the message reading function.

  As described above, in the fourth embodiment, by providing a response data size determination function, a data processing method can be selected according to the response data size at the time of execution.

As described above, in the present embodiment, in addition to the configuration of the third embodiment,
The service linkage device that has a response data size determination function that determines the response size and executes the data processing method according to the size has been described.

Embodiment 5 FIG.
The service cooperation apparatus 1000 according to the fifth embodiment adds the message writing function 10043 and the message reading function 10052 of the third embodiment to the configuration of the second embodiment as a combination of the second and third embodiments. The configuration.

Embodiment 6 FIG.
As a combination of the second and fourth embodiments, the service cooperation apparatus 1000 according to the sixth embodiment adds the message writing function 10043, message reading function 10052, and response data of the fourth embodiment to the configuration of the second embodiment. A configuration with a size determination function added.

Finally, a hardware configuration example of the service cooperation apparatus 1000 shown in the first to sixth embodiments will be described.
FIG. 22 is a diagram illustrating an example of hardware resources of the service cooperation apparatus 1000 illustrated in the first to sixth embodiments.
Note that the configuration of FIG. 22 is merely an example of the hardware configuration of the service cooperation apparatus 1000, and the hardware configuration of the service cooperation apparatus 1000 is not limited to the configuration illustrated in FIG. Also good.

In FIG. 22, the service cooperation apparatus 1000 includes a CPU 911 (also referred to as a central processing unit, a central processing unit, a processing unit, a processing unit, a microprocessor, a microcomputer, and a processor) that executes a program.
The CPU 911 is connected to, for example, a ROM (Read Only Memory) 913, a RAM (Random Access Memory) 914, a communication board 915, a display device 901, a keyboard 902, a mouse 903, and a magnetic disk device 920 via a bus 912. Control hardware devices.
Further, the CPU 911 may be connected to an FDD 904 (Flexible Disk Drive), a compact disk device 905 (CDD), a printer device 906, and a scanner device 907. Further, instead of the magnetic disk device 920, a storage device such as an SSD (Solid State Drive), an optical disk device, or a memory card (registered trademark) read / write device may be used.
The RAM 914 is an example of a volatile memory. The storage media of the ROM 913, the FDD 904, the CDD 905, and the magnetic disk device 920 are an example of a nonvolatile memory. These are examples of the storage device.
The “storage unit 1020” described in the first to sixth embodiments is realized by the RAM 914, the magnetic disk device 920, and the like.
A communication board 915, a keyboard 902, a mouse 903, a scanner device 907, and the like are examples of input devices.
The communication board 915, the display device 901, the printer device 906, and the like are examples of output devices.

The communication board 915 is connected to the network.
For example, the communication board 915 is connected to a LAN (local area network), the Internet, a WAN (wide area network), a SAN (storage area network), and the like.

The magnetic disk device 920 stores an operating system 921 (OS), a window system 922, a program group 923, and a file group 924.
The programs in the program group 923 are executed by the CPU 911 using the operating system 921 and the window system 922.

The RAM 914 temporarily stores at least part of the operating system 921 program and application programs to be executed by the CPU 911.
The RAM 914 stores various data necessary for processing by the CPU 911.

The ROM 913 stores a BIOS (Basic Input Output System) program, and the magnetic disk device 920 stores a boot program.
When the service cooperation apparatus 1000 is activated, the BIOS program in the ROM 913 and the boot program in the magnetic disk device 920 are executed, and the operating system 921 is activated by the BIOS program and the boot program.

  The program group 923 stores programs for executing the functions described as “˜unit” (other than “storage unit 1020”, the same applies hereinafter) and “˜means” in the description of the first to sixth embodiments. Yes. The program is read and executed by the CPU 911.

In the file group 924, in the description of the first to sixth embodiments, “determination of”, “determination of”, “analysis of”, “designation of”, “generation of”, “creation of”. , "Duplicate of", "Assignment of", "Updating of", "Setting of", "Registering of", "Selection of", "Input of", "Output of", etc. Information, data, signal values, variable values, encryption keys / decryption keys, random values, and parameters indicating the results of the processing described are stored as items of “˜file” and “˜database”.
The “˜file” and “˜database” are stored in a recording medium such as a disk or a memory.
Information, data, signal values, variable values, and parameters stored in a storage medium such as a disk or memory are read out to the main memory or cache memory by the CPU 911 via a read / write circuit.
The read information, data, signal value, variable value, and parameter are used for CPU operations such as extraction, search, reference, comparison, calculation, calculation, processing, editing, output, printing, and display.
Information, data, signal values, variable values, and parameters are stored in the main memory, registers, cache memory, and buffers during the CPU operations of extraction, search, reference, comparison, calculation, processing, editing, output, printing, and display. It is temporarily stored in a memory or the like.
In addition, the arrows in the flowcharts described in the first to sixth embodiments mainly indicate input / output of data and signals.
Data and signal values are recorded on a recording medium such as a memory of the RAM 914, a flexible disk of the FDD 904, a compact disk of the CDD 905, a magnetic disk of the magnetic disk device 920, other optical disks, a mini disk, and a DVD.
Data and signals are transmitted online via a bus 912, signal lines, cables, or other transmission media.

In addition, in the description of the first to sixth embodiments, what is described as “to part” and “to means” may be “to circuit”, “to device”, and “to device”. It may be “˜step”, “˜procedure”, “˜processing”.
That is, the “service cooperation method” according to the present invention can be realized by the steps, procedures, and processes shown in the flowcharts described in the first to sixth embodiments.
In addition, what is described as “˜unit” and “˜means” may be realized by firmware stored in the ROM 913.
Alternatively, it may be implemented only by software, or only by hardware such as elements, devices, substrates, and wirings, by a combination of software and hardware, or by a combination of firmware.
Firmware and software are stored as programs in a recording medium such as a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, and a DVD.
The program is read by the CPU 911 and executed by the CPU 911.
That is, the program causes the computer to function as “to part” and “to means” in the first to sixth embodiments. Alternatively, the procedures and methods of “to part” and “to means” in the first to sixth embodiments are executed by a computer.

As described above, the service cooperation apparatus 1000 shown in the first to sixth embodiments includes a CPU that is a processing device, a memory that is a storage device, a magnetic disk, a keyboard that is an input device, a mouse, a communication board, and a display device that is an output device, and a communication device. A computer including a board or the like.
As described above, the functions indicated as “˜unit” and “˜means” are realized by using these processing devices, storage devices, input devices, and output devices.

  1000 service cooperation device, 1001 definition analysis unit, 1002 pipe management unit, 1003 service disclosure unit, 1004 pipe writing unit, 1005 pipe reading unit, 1006 pipe, 1008 service connection unit A, 1009 service connection unit B, 1010 service connection unit C 1011 Service connection unit D, 1020 storage unit, 1101 scenario definition, 1102 interface definition, and 1103 pipe allocation definition.

Claims (8)

A service cooperation device for linking two or more services implemented by any service application,
A plurality of service connection units that correspond to any one of a plurality of service applications and that transmit and receive variable values with the corresponding service application at the time of service linkage,
Before starting service linkage, analyze the linkage scenario showing the service linkage procedure, and for each variable used for service linkage, set the variable value during service linkage from the multiple service connections. A definition analysis unit that specifies an output service connection unit to output and an input service connection unit to input a variable value, and the input service connection unit and the input service connection unit that generate the input / output definition information indicated for each variable; ,
A storage unit that stores the input / output definition information generated by the definition analysis unit before service cooperation starts;
When linking services, based on the input / output definition information, a pipe that holds the variable value, a pipe writing means that inputs the variable value from the output service connection unit and writes the variable value to the pipe, and an input service that reads the variable value from the pipe A pipe reading unit for outputting to the connection unit, and a pipe management unit for generating each variable,
Each service connection
At the time of service linkage, the variable value received from the corresponding service application is output to the pipe writing means corresponding to the variable value, the variable value input from the pipe reading means is transmitted to the corresponding service application,
The definition analysis unit
As a result of analyzing the cooperation scenario, when one output service connection unit and two or more input service connection units are specified for any variable,
A duplicate write process that duplicates the variable value input from the output service connection and writes it in parallel to two or more pipes to two or more input service connections;
Read variable value from one pipe, duplicate the read variable value, output the variable value to the input service connection part of the pipe and write to the pipe to the other input service connection part. Specify
Generate I / O definition information that indicates either replication write processing or read replication processing for the variable,
The pipe management unit
One pipe writing means is generated for a variable in which either of the replication writing process and the reading replication process is indicated, and a pipe and a pipe reading means are generated for each input service connection unit.
For variables for which duplicate write processing is indicated, the created pipe write means executes duplicate write processing,
A service cooperation apparatus that causes a generated pipe reading unit to execute read and copy processing for a variable for which read and copy processing is indicated. The definition analysis unit
As a result of analyzing the cooperation scenario, for any variable, when there is no service connection part for inputting the variable value of the variable,
For the variable, specify only the output service connection without specifying the input service connection, and also input the variable value of the variable from the output service connection, and delete the variable value of the input variable Specify the delete process to
Generate input / output definition information that indicates the output service connection and deletion processing for the variable,
The pipe management unit
The service cooperation apparatus according to claim 1, wherein one pipe writing unit is generated for a variable for which deletion processing is indicated, and the generated pipe writing unit is caused to execute deletion processing. The service cooperation apparatus further includes:
A service provision request receiving unit that receives a service provision request for requesting provision of a service from a service utilization system that uses the service;
The definition analysis unit
Each time the service provision request receiving unit receives a service provision request, before service cooperation performed based on the service provision request starts,
Analyzing the cooperation scenario, specifying an output service connection section and an input service connection section for each variable used for service cooperation performed based on the service provision request, and specifying the specified output service connection section and the input service The service linkage apparatus according to claim 1, wherein the connection unit generates input / output definition information indicated for each variable. Each service connection
The response data stream including the variable value is received from the corresponding service application, and the received response data stream is output to the pipe writing means corresponding to the variable value included in the response data stream.
The pipe management unit
The pipe writing means for extracting a corresponding variable value from the response data stream input from the output service connection unit and writing the extracted variable value to the pipe is generated for each variable. The service linkage apparatus described in 1. The pipe management unit
For each variable, a pipe writing means that has a function of extracting a corresponding variable value from the response data stream input from the output service connection unit and writing an ESB (Enterprise service bus) message including the extracted variable value to the memory. Generate and
Generating pipe reading means for each variable, having a function of reading out an ESB message from the memory, extracting a corresponding variable value from the read ESB message, and outputting the extracted variable value to the input service connection unit; 5. The service cooperation apparatus according to claim 4, wherein The pipe management unit
If the data size of the corresponding variable value included in the response data stream from the output service connection unit is less than the predetermined threshold, the corresponding variable value is extracted from the response data stream input from the output service connection unit, and the extracted variable A pipe writing means for writing an ESB message including a value to a memory;
If the data size of the corresponding variable value included in the response data stream from the output service connection unit is greater than or equal to the threshold, the corresponding variable value is extracted from the response data stream input from the output service connection unit, and the extracted variable value is 6. The service cooperation apparatus according to claim 5, wherein pipe writing means for writing into the pipe is generated. A computer having a plurality of service connection units that correspond to any of a plurality of service applications and transmit / receive variable values to / from the corresponding service application at the time of service cooperation,
A service linkage method for linking two or more services implemented by any service application,
Before the service cooperation starts, the computer analyzes a cooperation scenario indicating a service cooperation procedure, and for each variable used for service cooperation, the service cooperation is performed from the plurality of service connection units. Specify an output service connection part that outputs variable values and an input service connection part that inputs variable values from time to time, and the specified output service connection part and input service connection part generate input / output definition information for each variable. A definition analysis step;
A storage step in which the computer stores the input / output definition information generated by the definition analysis step before service cooperation starts;
At the time of service cooperation, the computer, based on the input / output definition information, a pipe in which a variable value is held, a pipe writing means for inputting a variable value from an output service connection unit and writing it into the pipe, and a variable value from the pipe Pipe reading means for reading and outputting to the input service connection unit, and a pipe management step for generating for each variable,
Each service connection
At the time of service linkage, the variable value received from the corresponding service application is output to the pipe writing means corresponding to the variable value, the variable value input from the pipe reading means is transmitted to the corresponding service application,
In the definition analysis step,
As a result of analyzing the cooperation scenario, when one output service connection unit and two or more input service connection units are specified for any variable, the computer
A duplicate write process that duplicates the variable value input from the output service connection and writes it in parallel to two or more pipes to two or more input service connections;
Read variable value from one pipe, duplicate the read variable value, output the variable value to the input service connection part of the pipe and write to the pipe to the other input service connection part. Specify
Generate I / O definition information that indicates either replication write processing or read replication processing for the variable,
In the pipe management step,
The computer
One pipe writing means is generated for a variable in which either of the replication writing process and the reading replication process is indicated, and a pipe and a pipe reading means are generated for each input service connection unit.
For variables for which duplicate write processing is indicated, the created pipe write means executes duplicate write processing,
A service cooperation method, characterized by causing a generated pipe reading means to execute read and copy processing for a variable for which read and copy processing is indicated. Corresponding to one of a plurality of service applications, at the time of service cooperation, having a plurality of service connection units for sending and receiving variable values with the corresponding service application,
To a computer that links two or more services implemented by any service application,
Before starting service linkage, analyze the linkage scenario showing the service linkage procedure, and for each variable used for service linkage, set the variable value during service linkage from the multiple service connections. A definition analysis step that specifies an output service connection part to be output and an input service connection part to which a variable value is input, and the specified output service connection part and the input service connection part generate input / output definition information for each variable; ,
A storage step for storing the input / output definition information generated by the definition analysis step before the cooperation of the service is started;
When linking services, based on the input / output definition information, a pipe that holds the variable value, a pipe writing means that inputs the variable value from the output service connection unit and writes the variable value to the pipe, and an input service that reads the variable value from the pipe A pipe reading means for outputting to the connection unit, and a pipe management step for generating each variable,
Each service connection
At the time of service linkage, the variable value received from the corresponding service application is output to the pipe writing means corresponding to the variable value, the variable value input from the pipe reading means is transmitted to the corresponding service application,
In the definition analysis step,
As a result of analyzing the cooperation scenario, when one output service connection unit and two or more input service connection units are specified for any variable,
A duplicate write process that duplicates the variable value input from the output service connection and writes it in parallel to two or more pipes to two or more input service connections;
Read variable value from one pipe, duplicate the read variable value, output the variable value to the input service connection part of the pipe and write to the pipe to the other input service connection part. Let me specify
Generate input / output definition information that indicates either replication write processing or read replication processing for the variable,
In the pipe management step,
In the computer,
One pipe writing means is generated for a variable in which either the replication writing process or the reading replication process is indicated, and a pipe and a pipe reading means are generated for each input service connection unit.
For the variable for which the replication writing process is indicated, the replication writing process is executed by the generated pipe writing means,
A program that causes a read pipe process to be executed by a generated pipe reading unit for a variable for which a read process is indicated.

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