connectionreconnectcommand.java

对eclipse gef进行封装,可以生成图形化编辑器

/*******************************************************************************
 * $Header: /cvsroot/EOS6/work_dir/niegy/com.primeton.studio.gef.ui/src/com/primeton/studio/gef/ui/commands/ConnectionReconnectCommand.java,v 1.2 2006/12/30 02:45:04 niegy Exp $
 * $Revision: 1.2 $
 * $Date: 2006/12/30 02:45:04 $
 *
 *==============================================================================
 *
 * Copyright (c) 2001-2006 Primeton Technologies, Ltd.
 * All rights reserved. 
 * 
 * Created on 2006-9-28
 *******************************************************************************/


package com.primeton.studio.gef.ui.commands;


import java.util.Iterator;
import java.util.List;

import org.eclipse.gef.commands.Command;

import com.primeton.studio.gef.core.Connection;
import com.primeton.studio.gef.core.NodeElement;
/**
 * TODO此处填写 class 信息
 *
 * @author niegy (mailto:[e-mail])
 */
/*
 * 修改历史
 * $Log: ConnectionReconnectCommand.java,v $
 * Revision 1.2  2006/12/30 02:45:04  niegy
 * 重构代码
 *
 * Revision 1.1  2006/11/17 03:15:13  niegy
 * create
 * 
 */
public class ConnectionReconnectCommand extends Command {
	
	/** The connection instance to reconnect. */
	private Connection connection;
	/** The new source endpoint. */
	private NodeElement newSource;
	/** The new target endpoint. */
	private NodeElement newTarget;
	/** The original source endpoint. */
	private final NodeElement oldSource;
	/** The original target endpoint. */
	private final NodeElement oldTarget;
	
	/**
	 * Instantiate a command that can reconnect a Connection instance to a different source
	 * or target endpoint.
	 * @param conn the connection instance to reconnect (non-null)
	 * @throws IllegalArgumentException if conn is null
	 */
	public ConnectionReconnectCommand(Connection conn) {
		if (conn == null) {
			throw new IllegalArgumentException();
		}
		this.connection = conn;
		this.oldSource = conn.getSourceNode();
		this.oldTarget = conn.getTargetNode();
	}
	
	private int getConnectIndex(List list){
	    for (int i = 0;i<list.size(); i++) {
            Connection element = (Connection) list.get(i);
            if(element.equals(connection))
                return i;
        }
	    return -1;
	}
	
	/* (non-Javadoc)
	 * @see org.eclipse.gef.commands.Command#canExecute()
	 */
	public boolean canExecute() {
	    boolean flag =true;	    
	    if (newSource != null) {
			 if(!checkSourceReconnection())
			     flag = false;
		}
		else if (newTarget != null) {
			if(! checkTargetReconnection())
			    flag =false;
		}		
		return flag;
	}
	
	/**
	 * Return true, if reconnecting the connection-instance to newSource is allowed.
	 */
	private boolean checkSourceReconnection() {
		// connection endpoints must be different Shapes
		if (newSource.equals(oldTarget)) {
			return false;
		}
		// return false, if the connection exists already
		for (Iterator iter = newSource.getSourceConnections().iterator(); iter.hasNext();) {
            Connection conn = (Connection) iter.next();
			// return false if a newSource -> oldTarget connection exists already
			// and it is a different instance than the connection-field
			if (conn.getTargetNode().equals(oldTarget) &&  !conn.equals(connection)) {
				return false;
			}
		}
		return true;
	}
	
	/**
	 * Return true, if reconnecting the connection-instance to newTarget is allowed. 
	 */
	private boolean checkTargetReconnection() {
		// connection endpoints must be different Shapes
		if (newTarget.equals(oldSource)) {
			return false;
		}
		// return false, if the connection exists already
		for (Iterator iter = newTarget.getTargetConnections().iterator(); iter.hasNext();) {
            Connection conn = (Connection) iter.next();
			// return false if a oldSource -> newTarget connection exists already
			// and it is a differenct instance that the connection-field
			if (conn.getSourceNode().equals(oldSource) && !conn.equals(connection)) {
				return false;
			}
		}
		return true;
	}	

	/**
	 * Reconnect the connection to newSource (if setNewSource(...) was invoked before)
	 * or newTarget (if setNewTarget(...) was invoked before).
	 */
	public void execute() {		
		if (newSource != null) {
			oldSource.getSourceConnections().remove(connection);
			connection.setSourceNode(newSource);
			connection.setTargetNode(oldTarget);
			newSource.getSourceConnections().add(connection);
		}
		else if (newTarget != null) {
			oldTarget.getTargetConnections().remove(connection);
			connection.setSourceNode(oldSource);
			connection.setTargetNode(newTarget);
			newTarget.getTargetConnections().add(connection);
		}
		else {
			throw new IllegalStateException("Should not happen");
		}
	}
	
	/**
	 * Set a new source endpoint for this connection.
	 * When execute() is invoked, the source endpoint of the connection will be attached
	 * to the supplied Shape instance.
	 * <p>
	 * Note: Calling this method, deactivates reconnection of the <i>target</i> endpoint.
	 * A single instance of this command can only reconnect either the source or the target 
	 * endpoint.
	 * </p>
	 * @param connectionSource a non-null Shape instance, to be used as a new source endpoint
	 * @throws IllegalArgumentException if connectionSource is null
	 */
	public void setNewSource(NodeElement connectionSource) {
		if (connectionSource == null) {
			throw new IllegalArgumentException();
		}
		setLabel("move connection startpoint");
		newSource = connectionSource;
		newTarget = null;
	}
	
	/**
	 * Set a new target endpoint for this connection
	 * When execute() is invoked, the target endpoint of the connection will be attached
	 * to the supplied Shape instance.
	 * <p>
	 * Note: Calling this method, deactivates reconnection of the <i>source</i> endpoint.
	 * A single instance of this command can only reconnect either the source or the target 
	 * endpoint.
	 * </p>
	 * @param connectionTarget a non-null Shape instance, to be used as a new target endpoint
	 * @throws IllegalArgumentException if connectionTarget is null
	 */
	public void setNewTarget(NodeElement connectionTarget) {
		if (connectionTarget == null) {
			throw new IllegalArgumentException();
		}
		setLabel("move connection endpoint");
		newSource = null;
		newTarget = connectionTarget;
	}
	
	/**
	 * Reconnect the connection to its original source and target endpoints.
	 */
	public void undo() {
	    if(newSource!=null)
	        newSource.getSourceConnections().remove(connection);
	    else 
	        oldSource.getSourceConnections().remove(connection);
	    
	    if(newTarget!=null)
	        newTarget.getTargetConnections().remove(connection);
	    else
	        oldTarget.getTargetConnections().remove(connection);
		
	    connection.setSourceNode(oldSource);
		connection.setTargetNode(oldTarget);
		oldSource.getSourceConnections().add(connection);
		oldTarget.getTargetConnections().add(connection);
		
	}
	
}