bundles/org.eclipse.jface.databinding/src/org/eclipse/jface/internal/databinding/viewers/CheckboxViewerCheckedElementsProperty.java

/*******************************************************************************
 * Copyright (c) 2008, 2010 Matthew Hall 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:
 *     Matthew Hall - initial API and implementation (bug 194734)
 *     Matthew Hall - bugs 195222, 259380, 263413, 265561
 ******************************************************************************/

package org.eclipse.jface.internal.databinding.viewers;

import java.util.Collections;
import java.util.Iterator;
import java.util.Set;

import org.eclipse.core.databinding.observable.Diffs;
import org.eclipse.core.databinding.observable.set.SetDiff;
import org.eclipse.core.databinding.property.INativePropertyListener;
import org.eclipse.core.databinding.property.IProperty;
import org.eclipse.core.databinding.property.ISimplePropertyListener;
import org.eclipse.core.databinding.property.NativePropertyListener;
import org.eclipse.jface.databinding.viewers.ViewerSetProperty;
import org.eclipse.jface.viewers.CheckStateChangedEvent;
import org.eclipse.jface.viewers.ICheckStateListener;
import org.eclipse.jface.viewers.ICheckable;
import org.eclipse.jface.viewers.StructuredViewer;
import org.eclipse.jface.viewers.Viewer;

/**
 * @param <S>
 * @since 3.3
 * 
 */
public abstract class CheckboxViewerCheckedElementsProperty<S extends Viewer>
		extends ViewerSetProperty<S, Object> {
	private final Object elementType;

	/**
	 * @param elementType
	 */
	public CheckboxViewerCheckedElementsProperty(Object elementType) {
		this.elementType = elementType;
	}

	public Object getElementType() {
		return elementType;
	}

	public Class<Object> getElementClass() {
		return Object.class;
	}

	protected final Set<Object> createElementSet(StructuredViewer viewer) {
		return ViewerElementSet.withComparer(viewer.getComparer());
	}

	protected void doUpdateSet(S source, SetDiff<Object> diff) {
		ICheckable checkable = (ICheckable) source;
		for (Iterator<Object> it = diff.getAdditions().iterator(); it.hasNext();)
			checkable.setChecked(it.next(), true);
		for (Iterator<Object> it = diff.getRemovals().iterator(); it.hasNext();)
			checkable.setChecked(it.next(), false);
	}

	public INativePropertyListener<S> adaptListener(
			ISimplePropertyListener<SetDiff<Object>> listener) {
		return new CheckStateListener(this, listener);
	}

	private class CheckStateListener extends
			NativePropertyListener<S, SetDiff<Object>> implements
			ICheckStateListener {
		private CheckStateListener(IProperty property,
				ISimplePropertyListener<SetDiff<Object>> listener) {
			super(property, listener);
		}

		public void checkStateChanged(CheckStateChangedEvent event) {
			Object element = event.getElement();
			boolean checked = event.getChecked();
			Set<Object> elementSet = createElementSet((StructuredViewer) event
					.getCheckable());
			elementSet.add(element);
			Set<Object> additions = checked ? elementSet : Collections
					.emptySet();
			Set<Object> removals = checked ? Collections.emptySet()
					: elementSet;
			SetDiff<Object> diff = Diffs.createSetDiff(additions, removals);
			fireChange(event.getSource(), diff);
		}

		public void doAddTo(S source) {
			((ICheckable) source).addCheckStateListener(this);
		}

		public void doRemoveFrom(S source) {
			((ICheckable) source).removeCheckStateListener(this);
		}
	}

	public String toString() {
		String s = "ICheckable.checkedElements{}"; //$NON-NLS-1$
		if (elementType != null)
			s += " <" + elementType + ">"; //$NON-NLS-1$//$NON-NLS-2$
		return s;
	}
}