Java开发图文混排的编辑器

				/*
				 * Created on 2004-7-18
				 * Author: Xuefeng, Copyright (C) 2004, Xuefeng.
				 */
				package jexi.core.command;
				
				/**
				 * Command interface.
				 * 
				 * @author Xuefeng
				 */
				public interface Command {
				
				    /**
				     * Execute this command. If succeeded (return TRUE), the 
				     * CommandManager will put this command into command list 
				     * if this command can support undo. 
				     * 
				     * @return True if the command executed succussfully.
				     */
				    boolean execute();
				
				    /**
				     * Undo this command. This is used to implement "Undo"
				     */
				    void unexecute();
				
				    /**
				     * If this command can support undo. Some commands not support 
				     * undo such as CopyCommand, PastCommand. 
				     * 
				     * @return True if this command can undo.
				     */
				    boolean canUndo();
				
				    /**
				     * Get the command detail. 
				     * 
				     * @return The command description.
				     */
				    String toString();
				}