/*******************************************************************************
* 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.eclipse.jdt.internal.ui.viewsupport;
import org.eclipse.jface.viewers.Viewer;
import org.eclipse.jface.viewers.ViewerFilter;
/**
* filter with a live cycle
*/
public abstract class JavaViewerFilter extends ViewerFilter {
private int fCount= 0;
/**
* To be overridden by implement
*/
protected abstract void initFilter();
protected abstract void freeFilter();
public final void filteringStart() {
if (fCount == 0)
initFilter();
fCount++;
}
public final void filteringEnd() {
fCount--;
if (fCount == 0)
freeFilter();
}
/*
* Overrides method from ViewerFilter
*/
@Override
public Object[] filter(Viewer viewer, Object parent, Object[] elements) {
try {
filteringStart();
return super.filter(viewer, parent, elements);
} finally {
filteringEnd();
}
}
}