Java Observable Properties

This project contains properties which are able to notify registered listeners about changes.

Usage

Insert dependency into your maven pom.xml:

<dependency>
  <groupId>de.borisskert</groupId>
  <artifactId>java-observable-properties</artifactId>
  <version>0.1.0-17</version>
</dependency>

Simple object properties

Simple properties are forced to contain a value. For optional values consider to use an OptionalProperty instance.

Generic object property

Instance creation

Property<Object> property = new SimpleObjectProperty<>(new Object());

Retrieve the value

Object object = property.get();

Update the value

property.set(new Object());

Register a listener

“Classical style”

public class MyChangeListener implements ChangeListener<Object> {
    @Override
    public void onChange(ReadonlyProperty<Object> property, Object oldValue, Object newValue) {
        // property: the property instance which is currently notifying this listener
        // oldValue: the value before this change occurred
        // newValue: the new value
    }
}
ChangeListener<Object> listener = new MyChangeListener();
property.addListener(listener);

Anonymous class

property.addListener(new ChangeListener<TestObject>() {
    @Override
    public void onChange(ReadonlyProperty<TestObject> property, TestObject oldValue, TestObject newValue) {
        // property: the property instance which is currently notifying this listener
        // oldValue: the value before this change occurred
        // newValue: the new value
    }
});

Lambda style

property.addListener((property, oldValue, newValue) -> {
    // property: the property instance which is currently notifying this listener
    // oldValue: the value before this change occurred
    // newValue: the new value
});

Unregister a listener

property.removeListener(listener);

Bind a Property

property.bind(anotherProperty);

Unbind a Property

property.unbind(boundProperty);

Typed properties

String

Property<String> property = new StringProperty<>("your property value");

Integer

Property<Integer> property = new IntegerProperty<>(123);

Double

Property<Double> property = new DoubleProperty<>(1.23);

Boolean

Property<Boolean> property = new BooleanProperty<>(true);

Long

Property<Long> property = new LongProperty<>(123L);

Float

Property<Float> property = new FloatProperty<>(1.23f);

Short

short myShort = 123;
Property<Short> property = new ShortProperty<>(myShort);

Optional properties

Optional properties are able to be empty. Technically they contain a null value.

Generic optional property

Instance creation

OptionalProperty<Object> property = new SimpleOptionalProperty<>(new Object()); // this property is filled
OptionalProperty<Object> empty = new SimpleOptionalProperty<>(); // this one is empty

Retrieve the optional value

Optional<Object> maybeObject = property.asOptional();

Typed optional properties

String

OptionalProperty<String> property = new OptionalStringProperty<>("your property value");
OptionalProperty<String> empty = new OptionalStringProperty<>();

Integer

OptionalProperty<Integer> property = new OptionalIntegerProperty<>(123);
OptionalProperty<Integer> empty = new OptionalIntegerProperty<>();

Double

OptionalProperty<Double> property = new OptionalDoubleProperty<>(1.23);
OptionalProperty<Double> empty = new OptionalDoubleProperty<>();

Boolean

OptionalProperty<Boolean> property = new OptionalBooleanProperty<>(true);
OptionalProperty<Boolean> empty = new OptionalBooleanProperty<>();

Long

OptionalProperty<Long> property = new OptionalLongProperty<>(123L);
OptionalProperty<Long> empty = new OptionalLongProperty<>();

Float

OptionalProperty<Float> property = new OptionalFloatProperty<>(1.23f);
OptionalProperty<Float> empty = new OptionalFloatProperty<>();

Short

short myShort = 123;
OptionalProperty<Short> property = new OptionalShortProperty<>(myShort);
OptionalProperty<Short> empty = new OptionalShortProperty<>();