/*******************************************************************************
* Copyright (c) 2004, 2005 Elias Volanakis 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:
�*����Elias Volanakis - initial API and implementation
�*******************************************************************************/
package org.asem.eclipse.mii.model.commands;
import java.util.Iterator;
import org.asem.eclipse.mii.model.abs.AbstractModelShape;
import org.asem.eclipse.mii.model.abs.Connection;
import org.asem.eclipse.mii.model.abs.IShape;
import org.eclipse.gef.commands.Command;
/**
* A command to create a connection between two shapes. The command can be undone or redone.
* <p>
* This command is designed to be used together with a GraphicalNodeEditPolicy. To use this command properly, following
* steps are necessary:
* </p>
* <ol>
* <li>Create a subclass of GraphicalNodeEditPolicy.</li>
* <li>Override the <tt>getConnectionCreateCommand(...)</tt> method, to create a new instance of this class and put it
* into the CreateConnectionRequest.</li>
* <li>Override the <tt>getConnectionCompleteCommand(...)</tt> method, to obtain the Command from the ConnectionRequest,
* call setTarget(...) to set the target endpoint of the connection and return this command instance.</li>
* </ol>
*
* @see org.eclipse.gef.examples.shapes.parts.ShapeEditPart#createEditPolicies() for an example of the above procedure.
* @see org.eclipse.gef.editpolicies.GraphicalNodeEditPolicy
* @author Elias Volanakis
*/
@SuppressWarnings("rawtypes")
public class ConnectionCreateCommand extends Command {
/** The connection instance. */
private Connection connection;
/** The desired line style for the connection (dashed or solid). */
private final int lineStyle;
/** Start endpoint for the connection. */
private final AbstractModelShape source;
/** Target endpoint for the connection. */
private AbstractModelShape target;
/**
* Instantiate a command that can create a connection between two shapes.
*
* @param source
* the source endpoint (a non-null Shape instance)
* @param lineStyle
* the desired line style. See Connection#setLineStyle(int) for details
* @throws IllegalArgumentException
* if source is null
* @see Connection#setLineStyle(int)
*/
public ConnectionCreateCommand(AbstractModelShape source, int lineStyle) {
if (source == null) {
throw new IllegalArgumentException();
}
setLabel("connection creation");
this.source = source;
this.lineStyle = lineStyle;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.gef.commands.Command#canExecute()
*/
public boolean canExecute() {
// disallow source -> source connections
if (source.equals(target)) {
return false;
}
if (target != null && !((IShape)target).allowConnectFrom(source))
return false;
if (source != null && !((IShape)source).canConnectTo(target))
return false;
// return false, if the source -> target connection exists already
for (Iterator iter = source.getSourceConnections().iterator(); iter.hasNext();) {
Connection conn = (Connection) iter.next();
if (conn.getTarget().equals(target)) {
return false;
}
}
return true;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.gef.commands.Command#execute()
*/
public void execute() {
// create a new connection between source and target
connection = new Connection(source, target);
// use the supplied line style
connection.setLineStyle(lineStyle);
}
/*
* (non-Javadoc)
*
* @see org.eclipse.gef.commands.Command#redo()
*/
public void redo() {
connection.reconnect();
}
/**
* Set the target endpoint for the connection.
*
* @param target
* that target endpoint (a non-null Shape instance)
* @throws IllegalArgumentException
* if target is null
*/
public void setTarget(AbstractModelShape target) {
if (target == null) {
throw new IllegalArgumentException();
}
this.target = target;
}
/*
* (non-Javadoc)
*
* @see org.eclipse.gef.commands.Command#undo()
*/
public void undo() {
connection.disconnect();
}
}