javafx.collections.MapChangeListener Maven / Gradle / Ivy
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package javafx.collections;
/**
* Interface that receives notifications of changes to an ObservableMap.
* @param the key element type
* @param the value element type
* @since JavaFX 2.0
*/
public interface MapChangeListener {
/**
* An elementary change done to an ObservableMap.
* Change contains information about a put or remove operation.
* Note that put operation might remove an element if there was
* already a value associated with the same key. In this case
* wasAdded() and wasRemoved() will both return true.
*
* @param key type
* @param value type
* @since JavaFX 2.0
*/
public static abstract class Change {
private final ObservableMap map;
/**
* Constructs a change associated with a map.
* @param map the source of the change
*/
public Change(ObservableMap map) {
this.map = map;
}
/**
* An observable map that is associated with the change.
* @return the source map
*/
public ObservableMap getMap() {
return map;
}
/**
* If this change is a result of add operation.
* @return true if a new value (or key-value) entry was added to the map
*/
public abstract boolean wasAdded();
/**
* If this change is a result of removal operation.
* Note that an element might be removed even as a result of put operation.
* @return true if an old value (or key-value) entry was removed from the map
*/
public abstract boolean wasRemoved();
/**
* A key associated with the change.
* If the change is a remove change, the key no longer exist in a map.
* Otherwise, the key got set to a new value.
* @return the key that changed
*/
public abstract K getKey();
/**
* Get the new value of the key. Return null if this is a removal.
* @return the value that is now associated with the key
*/
public abstract V getValueAdded();
/**
* Get the old value of the key. This is null if and only if the value was
* added to the key that was not previously in the map.
* @return the value previously associated with the key
*/
public abstract V getValueRemoved();
}
/**
* Called after a change has been made to an ObservableMap.
* This method is called on every elementary change (put/remove) once.
* This means, complex changes like keySet().removeAll(Collection) or clear()
* may result in more than one call of onChanged method.
*
* @param change the change that was made
*/
void onChanged(Change change);
}