com.rcpcompany.uibindings.internal.observables.AbstractSWTObservableValue.java Source code

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Here is the source code for com.rcpcompany.uibindings.internal.observables.AbstractSWTObservableValue.java

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/*******************************************************************************
 * Copyright (c) 2006-2013 The RCP Company 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:
 *     The RCP Company - initial API and implementation
 *******************************************************************************/
package com.rcpcompany.uibindings.internal.observables;

import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.value.AbstractObservableValue;
import org.eclipse.jface.databinding.swt.ISWTObservableValue;
import org.eclipse.jface.databinding.swt.SWTObservables;
import org.eclipse.swt.events.DisposeEvent;
import org.eclipse.swt.events.DisposeListener;
import org.eclipse.swt.widgets.Widget;

/**
 * Copied strait out of
 * {@link org.eclipse.jface.internal.databinding.provisional.swt.AbstractSWTObservableValue}.
 */
public abstract class AbstractSWTObservableValue extends AbstractObservableValue implements ISWTObservableValue {

    private final Widget widget;

    /**
     * Standard constructor for an SWT ObservableValue. Makes sure that the observable gets disposed
     * when the SWT widget is disposed.
     * 
     * @param widget
     */
    protected AbstractSWTObservableValue(Widget widget) {
        this(SWTObservables.getRealm(widget.getDisplay()), widget);
    }

    /**
     * Constructor that allows for the setting of the realm. Makes sure that the observable gets
     * disposed when the SWT widget is disposed.
     * 
     * @param realm
     * @param widget
     */
    protected AbstractSWTObservableValue(Realm realm, Widget widget) {
        super(realm);
        this.widget = widget;
        widget.addDisposeListener(disposeListener);
    }

    @Override
    public synchronized void dispose() {
        if (!widget.isDisposed()) {
            widget.removeDisposeListener(disposeListener);
        }
        super.dispose();
    }

    /**
     * Dispose listener for the backed SWT widget. Not just added/removed in
     * {@link #firstListenerAdded()} and {@link #lastListenerRemoved()} as we want to track disposal
     * of the widget even if we don't have any listeners.
     */
    private final DisposeListener disposeListener = new DisposeListener() {
        @Override
        public void widgetDisposed(DisposeEvent e) {
            AbstractSWTObservableValue.this.dispose();
        }
    };

    /**
     * @return Returns the widget.
     */
    @Override
    public Widget getWidget() {
        return widget;
    }
}