javafx.beans.property.ObjectPropertyBase Maven / Gradle / Ivy
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package javafx.beans.property;
import javafx.beans.InvalidationListener;
import javafx.beans.Observable;
import javafx.beans.value.ChangeListener;
import javafx.beans.value.ObservableValue;
import com.sun.javafx.binding.ExpressionHelper;
import java.lang.ref.WeakReference;
import javafx.beans.WeakListener;
/**
* The class {@code ObjectPropertyBase} is the base class for a property
* wrapping an arbitrary {@code Object}.
*
* It provides all the functionality required for a property except for the
* {@link #getBean()} and {@link #getName()} methods, which must be implemented
* by extending classes.
*
* @see ObjectProperty
*
*
* @param
* the type of the wrapped value
* @since JavaFX 2.0
*/
public abstract class ObjectPropertyBase extends ObjectProperty {
private T value;
private ObservableValue observable = null;
private InvalidationListener listener = null;
private boolean valid = true;
private ExpressionHelper helper = null;
/**
* The constructor of the {@code ObjectPropertyBase}.
*/
public ObjectPropertyBase() {
}
/**
* The constructor of the {@code ObjectPropertyBase}.
*
* @param initialValue
* the initial value of the wrapped {@code Object}
*/
public ObjectPropertyBase(T initialValue) {
this.value = initialValue;
}
@Override
public void addListener(InvalidationListener listener) {
helper = ExpressionHelper.addListener(helper, this, listener);
}
@Override
public void removeListener(InvalidationListener listener) {
helper = ExpressionHelper.removeListener(helper, listener);
}
@Override
public void addListener(ChangeListener listener) {
helper = ExpressionHelper.addListener(helper, this, listener);
}
@Override
public void removeListener(ChangeListener listener) {
helper = ExpressionHelper.removeListener(helper, listener);
}
/**
* Sends notifications to all attached
* {@link javafx.beans.InvalidationListener InvalidationListeners} and
* {@link javafx.beans.value.ChangeListener ChangeListeners}.
*
* This method is called when the value is changed, either manually by
* calling {@link #set} or in case of a bound property, if the
* binding becomes invalid.
*/
protected void fireValueChangedEvent() {
ExpressionHelper.fireValueChangedEvent(helper);
}
private void markInvalid() {
if (valid) {
valid = false;
invalidated();
fireValueChangedEvent();
}
}
/**
* The method {@code invalidated()} can be overridden to receive
* invalidation notifications. This is the preferred option in
* {@code Objects} defining the property, because it requires less memory.
*
* The default implementation is empty.
*/
protected void invalidated() {
}
/**
* {@inheritDoc}
*/
@Override
public T get() {
valid = true;
return observable == null ? value : observable.getValue();
}
/**
* {@inheritDoc}
*/
@Override
public void set(T newValue) {
if (isBound()) {
throw new java.lang.RuntimeException((getBean() != null && getName() != null ?
getBean().getClass().getSimpleName() + "." + getName() + " : ": "") + "A bound value cannot be set.");
}
if (value != newValue) {
value = newValue;
markInvalid();
}
}
/**
* {@inheritDoc}
*/
@Override
public boolean isBound() {
return observable != null;
}
/**
* {@inheritDoc}
*/
@Override
public void bind(final ObservableValue newObservable) {
if (newObservable == null) {
throw new NullPointerException("Cannot bind to null");
}
if (!newObservable.equals(this.observable)) {
unbind();
observable = newObservable;
if (listener == null) {
listener = new Listener(this);
}
observable.addListener(listener);
markInvalid();
}
}
/**
* {@inheritDoc}
*/
@Override
public void unbind() {
if (observable != null) {
value = observable.getValue();
observable.removeListener(listener);
observable = null;
}
}
/**
* Returns a string representation of this {@code ObjectPropertyBase} object.
* @return a string representation of this {@code ObjectPropertyBase} object.
*/
@Override
public String toString() {
final Object bean = getBean();
final String name = getName();
final StringBuilder result = new StringBuilder("ObjectProperty [");
if (bean != null) {
result.append("bean: ").append(bean).append(", ");
}
if ((name != null) && (!name.equals(""))) {
result.append("name: ").append(name).append(", ");
}
if (isBound()) {
result.append("bound, ");
if (valid) {
result.append("value: ").append(get());
} else {
result.append("invalid");
}
} else {
result.append("value: ").append(get());
}
result.append("]");
return result.toString();
}
private static class Listener implements InvalidationListener, WeakListener {
private final WeakReference> wref;
public Listener(ObjectPropertyBase ref) {
this.wref = new WeakReference<>(ref);
}
@Override
public void invalidated(Observable observable) {
ObjectPropertyBase ref = wref.get();
if (ref == null) {
observable.removeListener(this);
} else {
ref.markInvalid();
}
}
@Override
public boolean wasGarbageCollected() {
return wref.get() == null;
}
}
}