LehnerPraktikum/src/command/CommandInvoker.java

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package command;

import command.CommandInterface;
import java.util.HashMap;
import java.util.Stack;


/**
 *
 * @author PC
 */
public class CommandInvoker {
    private HashMap<Object, CommandInterface> commands;
    private Stack<CommandInterface> undoStack;

    public CommandInvoker()
    {
        commands = new HashMap<>();
        undoStack = new Stack<>();
    }
    
    public void addCommand(Object key, CommandInterface value)
    {
        commands.put(key, value);
    }
    
    public void executeCommand(Object key)
    {
        CommandInterface cmd = commands.get(key);
        cmd.execute();
        if(cmd.isUndoable())
        {
            undoStack.push(cmd);
        }
    }
    
    public void undoCommand()
    {
        if(!undoStack.empty())
        {
            undoStack.pop().undo();
        }
    }
    
}