A Compose Desktop library for managing preferences and settings based on Java’s Preferences API
MaleficPrefs is a library that provides a convenient way to store and retrieve preferences in Compose Desktop applications. It’s built on top of Java’s Preferences API and offers two main features:
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Property Delegates: Type-safe property delegates for storing primitive types and serializable objects
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Persistent Collections: Collections that automatically persist their state to preferences
MaleficPrefs provides property delegates for various types. These delegates automatically handle the storage and retrieval of values from preferences.
// Define a boolean preference with a key and default value
var darkMode by BooleanPreference("darkMode", defaultValue = false)
// Use it like a regular property
darkMode = true
println(darkMode) // true// Define an integer preference with a key and default value
var counter by IntPreference("counter", defaultValue = 0)
// Use it like a regular property
counter = 42
println(counter) // 42// Define a string preference with a key and default value
var username by StringPreference("username", defaultValue = "")
// Use it like a regular property
username = "JohnDoe"
println(username) // JohnDoe// Define a double preference with a key and default value
var price by DoublePreference("price", defaultValue = 0.0)
// Use it like a regular property
price = 99.99
println(price) // 99.99// Define a float preference with a key and default value
var rating by FloatPreference("rating", defaultValue = 0.0f)
// Use it like a regular property
rating = 4.5f
println(rating) // 4.5// Define a long preference with a key and default value
var timestamp by LongPreference("timestamp", defaultValue = 0L)
// Use it like a regular property
timestamp = System.currentTimeMillis()
println(timestamp)// Define a byte array preference with a key and default value
var data by ByteArrayPreference("data", defaultValue = byteArrayOf())
// Use it like a regular property
data = byteArrayOf(1, 2, 3)
println(data.contentToString()) // [1, 2, 3]// Define a data class that implements Serializable
data class User(val name: String, val age: Int) : Serializable
// Define a serializable preference with a key and default value
var currentUser by SerializablePreference("currentUser", User("Guest", 0))
// Use it like a regular property
currentUser = User("John", 30)
println(currentUser) // User(name=John, age=30)MaleficPrefs also provides nullable variants of the property delegates. These delegates allow you to store null values, which will be replaced with the default value when retrieved.
// Define a nullable integer preference with a key and default value
var nullableCounter by NullableIntPreference("nullableCounter", defaultValue = 0)
// Use it like a regular property
nullableCounter = 42
println(nullableCounter) // 42
// Assign null to use the default value
nullableCounter = null
println(nullableCounter) // 0 (default value)// Define a nullable string preference with a key and default value
var nullableUsername by NullableStringPreference("nullableUsername", defaultValue = "Guest")
// Use it like a regular property
nullableUsername = "JohnDoe"
println(nullableUsername) // JohnDoe
// Assign null to use the default value
nullableUsername = null
println(nullableUsername) // Guest (default value)// Define a nullable double preference with a key and default value
var nullablePrice by NullableDoublePreference("nullablePrice", defaultValue = 0.0)
// Use it like a regular property
nullablePrice = 99.99
println(nullablePrice) // 99.99
// Assign null to use the default value
nullablePrice = null
println(nullablePrice) // 0.0 (default value)// Define a nullable float preference with a key and default value
var nullableRating by NullableFloatPreference("nullableRating", defaultValue = 0.0f)
// Use it like a regular property
nullableRating = 4.5f
println(nullableRating) // 4.5
// Assign null to use the default value
nullableRating = null
println(nullableRating) // 0.0 (default value)// Define a nullable long preference with a key and default value
var nullableTimestamp by NullableLongPreference("nullableTimestamp", defaultValue = 0L)
// Use it like a regular property
nullableTimestamp = System.currentTimeMillis()
println(nullableTimestamp)
// Assign null to use the default value
nullableTimestamp = null
println(nullableTimestamp) // 0 (default value)// Define a nullable byte array preference with a key and default value
var nullableData by NullableByteArrayPreference("nullableData", defaultValue = byteArrayOf())
// Use it like a regular property
nullableData = byteArrayOf(1, 2, 3)
println(nullableData.contentToString()) // [1, 2, 3]
// Assign null to use the default value
nullableData = null
println(nullableData.contentToString()) // [] (default value)MaleficPrefs provides persistent collections that automatically save their state to preferences. These collections implement the standard Java collection interfaces, so you can use them just like regular collections.
// Create a persistent ArrayList with a key
val todoList = PersistentArrayList<String>("todoList")
// Add items
todoList.add("Buy groceries")
todoList.add("Clean the house")
// Remove items
todoList.remove("Buy groceries")
// Reset the list
todoList.reset()
// The list state is automatically persisted
// When you create a new instance with the same key, it will load the saved state
val loadedList = PersistentArrayList<String>("todoList")
println(loadedList) // []// Create a persistent HashMap with a key
val userSettings = PersistentHashMap<String, String>("userSettings")
// Add entries
userSettings["theme"] = "dark"
userSettings["language"] = "en"
// Remove entries
userSettings.remove("theme")
// Add multiple entries
userSettings.putAll(mapOf("fontSize" to "14", "fontFamily" to "Arial"))
// Reset the map
userSettings.reset()
// The map state is automatically persisted
// When you create a new instance with the same key, it will load the saved state
val loadedSettings = PersistentHashMap<String, String>("userSettings")
println(loadedSettings) // {}// Create a persistent HashSet with a key
val enabledFeatures = PersistentHashSet<String>("enabledFeatures")
// Add items
enabledFeatures.add("darkMode")
enabledFeatures.add("notifications")
// Remove items
enabledFeatures.remove("darkMode")
// Reset the s
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et
enabledFeatures.reset()
// The set state is automatically persisted
// When you create a new instance with the same key, it will load the saved state
val loadedFeatures = PersistentHashSet<String>("enabledFeatures")
println(loadedFeatures) // []// Create a persistent Queue with a key
val messageQueue = PersistentQueue<String>("messageQueue")
// Add items
messageQueue.add("Message 1")
messageQueue.add("Message 2")
// Remove items
val message = messageQueue.poll() // "Message 1"
// Reset the queue
messageQueue.reset()
// The queue state is automatically persisted
// When you create a new instance with the same key, it will load the saved state
val loadedQueue = PersistentQueue<String>("messageQueue")
println(loadedQueue) // []The project is currently under active development. Feel free to contribute or report issues.
Contributions are what make the open source community such an amazing place to learn, inspire, and create. Any contributions you make are greatly appreciated.
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Open an issue first to discuss what you would like to change.
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Fork the Project
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Create your feature branch (
git checkout -b feature/amazing-feature) -
Commit your changes (
git commit -m 'Add some amazing feature') -
Push to the branch (
git push origin feature/amazing-feature) -
Open a pull request
Please make sure to update tests as appropriate.
This project is licensed under the MIT License - see the LICENSE file for details.