/*******************************************************************************
 * Copyright (c) 2000, 2004 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Common Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/cpl-v10.html
 * 
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.jface.viewers;


/** 
 * A content provider mediates between the viewer's model
 * and the viewer itself.
 * 
 * @see org.eclipse.jface.viewers.ContentViewer#setContentProvider(IContentProvider)
 */
public interface IContentProvider {
/**
 * Disposes of this content provider.  
 * This is called by the viewer when it is disposed.
 * <p>
 * The viewer should not be updated during this call, as it is in the process
 * of being disposed.
 * </p>
 */
public void dispose();
/**
 * Notifies this content provider that the given viewer's input
 * has been switched to a different element.
 * <p>
 * A typical use for this method is registering the content provider as a listener
 * to changes on the new input (using model-specific means), and deregistering the viewer 
 * from the old input. In response to these change notifications, the content provider
 * should update the viewer (see the add, remove, update and refresh methods on the viewers).
 * </p>
 * <p>
 * The viewer should not be updated during this call, as it might be in the process
 * of being disposed.
 * </p>
 *
 * @param viewer the viewer
 * @param oldInput the old input element, or <code>null</code> if the viewer
 *   did not previously have an input
 * @param newInput the new input element, or <code>null</code> if the viewer
 *   does not have an input
 */
public void inputChanged(Viewer viewer, Object oldInput, Object newInput);
}
