com.sun.javafx.collections.ElementObserver Maven / Gradle / Ivy
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package com.sun.javafx.collections;
import javafx.collections.ObservableListBase;
import java.util.IdentityHashMap;
import java.util.Iterator;
import java.util.RandomAccess;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.util.Callback;
final class ElementObserver {
private static class ElementsMapElement {
InvalidationListener listener;
int counter;
public ElementsMapElement(InvalidationListener listener) {
this.listener = listener;
this.counter = 1;
}
public void increment() {
counter++;
}
public int decrement() {
return --counter;
}
private InvalidationListener getListener() {
return listener;
}
}
private Callback extractor;
private final Callback listenerGenerator;
private final ObservableListBase list;
private IdentityHashMap elementsMap =
new IdentityHashMap();
ElementObserver(Callback extractor, Callback listenerGenerator, ObservableListBase list) {
this.extractor = extractor;
this.listenerGenerator = listenerGenerator;
this.list = list;
}
void attachListener(final E e) {
if (elementsMap != null && e != null) {
if (elementsMap.containsKey(e)) {
elementsMap.get(e).increment();
} else {
InvalidationListener listener = listenerGenerator.call(e);
for (Observable o : extractor.call(e)) {
o.addListener(listener);
}
elementsMap.put(e, new ElementObserver.ElementsMapElement(listener));
}
}
}
void detachListener(E e) {
if (elementsMap != null && e != null) {
ElementObserver.ElementsMapElement el = elementsMap.get(e);
for (Observable o : extractor.call(e)) {
o.removeListener(el.getListener());
}
if (el.decrement() == 0) {
elementsMap.remove(e);
}
}
}
}