org.summer.sdt.internal.ui.AbstractJavaElementLabelDecorator.java Source code

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Here is the source code for org.summer.sdt.internal.ui.AbstractJavaElementLabelDecorator.java

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/*******************************************************************************
 * Copyright (c) 2000, 2011 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
 *******************************************************************************/
package org.summer.sdt.internal.ui;

import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.ListenerList;
import org.eclipse.jface.viewers.IDecoration;
import org.eclipse.jface.viewers.ILabelProviderListener;
import org.eclipse.jface.viewers.ILightweightLabelDecorator;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.summer.sdt.core.ElementChangedEvent;
import org.summer.sdt.core.IElementChangedListener;
import org.summer.sdt.core.IJavaElement;
import org.summer.sdt.core.IJavaElementDelta;
import org.summer.sdt.core.JavaCore;

public abstract class AbstractJavaElementLabelDecorator implements ILightweightLabelDecorator {

    private class DecoratorElementChangeListener implements IElementChangedListener {

        /**
         * {@inheritDoc}
         */
        public void elementChanged(ElementChangedEvent event) {
            List<IJavaElement> changed = new ArrayList<IJavaElement>();
            processDelta(event.getDelta(), changed);
            if (changed.size() == 0)
                return;

            fireChange(changed.toArray(new IJavaElement[changed.size()]));
        }

    }

    private ListenerList fListeners;
    private IElementChangedListener fChangeListener;

    /**
     * {@inheritDoc}
     */
    public void addListener(ILabelProviderListener listener) {
        if (fChangeListener == null) {
            fChangeListener = new DecoratorElementChangeListener();
            JavaCore.addElementChangedListener(fChangeListener);
        }

        if (fListeners == null) {
            fListeners = new ListenerList();
        }

        fListeners.add(listener);
    }

    /**
     * {@inheritDoc}
     */
    public void dispose() {
        if (fChangeListener != null) {
            JavaCore.removeElementChangedListener(fChangeListener);
            fChangeListener = null;
        }
        if (fListeners != null) {
            Object[] listeners = fListeners.getListeners();
            for (int i = 0; i < listeners.length; i++) {
                fListeners.remove(listeners[i]);
            }
            fListeners = null;
        }
    }

    /**
     * {@inheritDoc}
     */
    public boolean isLabelProperty(Object element, String property) {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    public void removeListener(ILabelProviderListener listener) {
        if (fListeners == null)
            return;

        fListeners.remove(listener);

        if (fListeners.isEmpty() && fChangeListener != null) {
            JavaCore.removeElementChangedListener(fChangeListener);
            fChangeListener = null;
        }
    }

    private void fireChange(IJavaElement[] elements) {
        if (fListeners != null && !fListeners.isEmpty()) {
            LabelProviderChangedEvent event = new LabelProviderChangedEvent(this, elements);
            Object[] listeners = fListeners.getListeners();
            for (int i = 0; i < listeners.length; i++) {
                ((ILabelProviderListener) listeners[i]).labelProviderChanged(event);
            }
        }
    }

    /**
     * {@inheritDoc}
     */
    public abstract void decorate(Object element, IDecoration decoration);

    protected abstract void processDelta(IJavaElementDelta delta, List<IJavaElement> result);

    protected boolean processChildrenDelta(IJavaElementDelta delta, List<IJavaElement> result) {
        IJavaElementDelta[] children = delta.getAffectedChildren();
        for (int i = 0; i < children.length; i++) {
            processDelta(children[i], result);
        }
        return false;
    }

}