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/*******************************************************************************
* Copyright (c) 2006, 2008 IBM Corporation and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* IBM Corporation - initial API and implementation
* Brad Reynolds - bug 164653
* Matthew Hall - bugs 208332, 263691
*******************************************************************************/
package org.eclipse.core.databinding.observable.value;
import org.eclipse.core.databinding.observable.AbstractObservable;
import org.eclipse.core.databinding.observable.ObservableTracker;
import org.eclipse.core.databinding.observable.Realm;
/**
*
* <p>
* This class is thread safe. All state accessing methods must be invoked from
* the {@link Realm#isCurrent() current realm}. Methods for adding and removing
* listeners may be invoked from any thread.
* </p>
* @since 1.0
*
*/
abstract public class AbstractObservableValue extends AbstractObservable implements IObservableValue {
/**
* Constructs a new instance with the default realm.
*/
public AbstractObservableValue() {
this(Realm.getDefault());
}
/**
* @param realm
*/
public AbstractObservableValue(Realm realm) {
super(realm);
}
public synchronized void addValueChangeListener(IValueChangeListener listener) {
addListener(ValueChangeEvent.TYPE, listener);
}
public synchronized void removeValueChangeListener(IValueChangeListener listener) {
removeListener(ValueChangeEvent.TYPE, listener);
}
final public void setValue(Object value) {
checkRealm();
doSetValue(value);
}
/**
* Template method for setting the value of the observable. By default the
* method throws an {@link UnsupportedOperationException}.
*
* @param value
*/
protected void doSetValue(Object value) {
throw new UnsupportedOperationException();
}
protected void fireValueChange(ValueDiff diff) {
// fire general change event first
super.fireChange();
fireEvent(new ValueChangeEvent(this, diff));
}
public final Object getValue() {
getterCalled();
return doGetValue();
}
abstract protected Object doGetValue();
public boolean isStale() {
getterCalled();
return false;
}
private void getterCalled() {
ObservableTracker.getterCalled(this);
}
protected void fireChange() {
throw new RuntimeException(
"fireChange should not be called, use fireValueChange() instead"); //$NON-NLS-1$
}
}
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