PraktikumCommandDesingPattern/src/commands/CommandInvoker.java

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package commands;

import java.awt.Component;
import java.util.HashMap;
import java.util.Stack;

/**
 * Command Invoker
 * ordnet den verschiedenen Events die Kommandos zu
 * speichert die letzten Kommandos im Stack
 * @author matthias
 */
public class CommandInvoker {
    private HashMap<Component, CommandInterface> commands;
    private Stack<CommandInterface> undoStack;
    
    public CommandInvoker()
    {
        this.commands = new HashMap<>();
        this.undoStack = new Stack<>();
    }
    
    public void addCommand(Component key, CommandInterface val)
    {
        this.commands.put(key, val);
    }
    
    /**
     * führt das zugehörige Kommand zum Key(Object) aus
     * @param key (Objekt)
     */
    public void executeCommand(Component key)
    {
        this.commands.get(key).execute();
        this.undoStack.push(this.commands.get(key));
    }
     /**
     * führt das zugehörige undo vom letzten Kommand aus
     */
    public void undoCommand()
    {
      if (!this.undoStack.isEmpty())
      {
        this.undoStack.pop().undo();
      }
    }
}