AbstractEditPolicy.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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.gef.editpolicies;

import org.eclipse.gef.EditPart;
import org.eclipse.gef.EditPolicy;
import org.eclipse.gef.Request;
import org.eclipse.gef.RequestConstants;
import org.eclipse.gef.commands.Command;

/**
 * The default implementation of {@link EditPolicy}.
 * <P>
 * Since this is the default implementation of an interface, this document deals with
 * proper sub-classing.  This class is not the API.  For documentation on proper usage of
 * the public API, see the documentation for the interface itself: {@link EditPolicy}.
 */
public abstract class AbstractEditPolicy
	implements EditPolicy, RequestConstants
{

private EditPart host;

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#activate()
 */
public void activate() { }

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#deactivate()
 */
public void deactivate() { }

/**
 * This method will log the message to GEF's trace/debug system if the corrseponding flag
 * for FEEDBACK is set to true.
 * @param message the String to log
 * @deprecated in 3.1  This method will be removed in future releases.
 */
protected final void debugFeedback(String message) {
}

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#eraseSourceFeedback(Request)
 */
public void eraseSourceFeedback(Request request) { }

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#eraseTargetFeedback(Request)
 */
public void eraseTargetFeedback(Request request) { }

/**
 * Returns <code>null</code> by default. <code>null</code> is used to indicate that the
 * EditPolicy does not contribute to the specified <code>Request</code>.
 * @see org.eclipse.gef.EditPolicy#getCommand(Request)
 */
public Command getCommand(Request request) {
	return null;
}

/**
 * @see org.eclipse.gef.EditPolicy#getHost()
 */
public EditPart getHost() {
	return host;
}
/**
 * Returns <code>null</code> by default. <code>null</code> indicates that this policy is
 * unable to determine the target for the specified <code>Request</code>.
 * @see org.eclipse.gef.EditPolicy#getTargetEditPart(Request)
 */
public EditPart getTargetEditPart(Request request) {
	return null;
}

/**
 * @see org.eclipse.gef.EditPolicy#setHost(EditPart)
 */
public void setHost(EditPart host) {
	this.host = host;
}

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#showSourceFeedback(Request)
 */
public void showSourceFeedback(Request request) { }

/**
 * Does nothing by default.
 * @see org.eclipse.gef.EditPolicy#showTargetFeedback(Request)
 */
public void showTargetFeedback(Request request) { }

/**
 * @see java.lang.Object#toString()
 */
public String toString() {
	String c = getClass().getName();
	c = c.substring(c.lastIndexOf('.') + 1);
	if (getHost() != null) {
		return getHost().toString() + "." + c; //$NON-NLS-1$
	} else {
		return c + " (no host for EditPolicy set yet)"; //$NON-NLS-1$
	}
}

/**
 * Returns <code>false</code> by default.
 * @see org.eclipse.gef.EditPolicy#understandsRequest(Request)
 */
public boolean understandsRequest(Request req) {
	return false;
}

}