/*******************************************************************************
 * Copyright (c) 2007 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.ui;

import java.util.Map;

import org.eclipse.jface.util.IPropertyChangeListener;

/**
 * A part can provide arbitrary properties. The properties will be persisted
 * between sessions by the part reference, and will be available from the part
 * reference as well as the part. The properties can only be set on a part, not
 * on the reference. The properties will be available to the IPresentablePart.
 * <p>
 * Setting a property must fire a PropertyChangeEvent.
 * </p>
 * 
 * @since 3.3
 */
public interface IWorkbenchPart3 extends IWorkbenchPart2 {
	/**
	 * Add a listener for changes in the arbitrary properties set.
	 * <p>
	 * <b>Note: this is a different set of properties than the ones covered
	 * by the IWorkbenchPartConstants.PROP_* constants.
	 * </p>
	 * 
	 * @param listener
	 *            Must not be <code>null.
	 */
	public void addPartPropertyListener(IPropertyChangeListener listener);

	/**
	 * Remove a change listener from the arbitrary properties set.
	 * <p>
	 * <b>Note: this is a different set of properties than the ones covered
	 * by the IWorkbenchPartConstants.PROP_* constants.
	 * </p>
	 * 
	 * @param listener
	 *            Must not be <code>null.
	 */
	public void removePartPropertyListener(IPropertyChangeListener listener);

	/**
	 * Return the value for the arbitrary property key, or <code>null.
	 * 
	 * @param key
	 *            the arbitrary property. Must not be <code>null.
	 * @return the property value, or <code>null.
	 */
	public String getPartProperty(String key);

	/**
	 * Set an arbitrary property on the part. It is the implementor's
	 * responsibility to fire the corresponding PropertyChangeEvent.
	 * <p>
	 * A default implementation has been added to WorkbenchPart.
	 * </p>
	 * 
	 * @param key
	 *            the arbitrary property. Must not be <code>null.
	 * @param value
	 *            the property value. A <code>null value will remove
	 *            that property.
	 */
	public void setPartProperty(String key, String value);

	/**
	 * Return an unmodifiable map of the arbitrary properties. This method can
	 * be used to save the properties during workbench save/restore.
	 * 
	 * @return A Map of the properties. Must not be <code>null.
	 */
	public Map getPartProperties();
}