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package controller;

import java.util.HashMap;
import java.util.Stack;

/**
 *
 * @author jechowma68968
 */
public class Invoker
{
  private HashMap<Object, Interface> commands;
  private Stack commandHistory;
  
  public Invoker()
  {
    commands = new HashMap<>();
    commandHistory = new Stack();
  }
  
  /**
   * 
   * @param key ist das Object
   * @param value ist auch etwas
   */
  public void addCommand(Object key, Interface value){
    commands.put(key, value);
  }
  
  public void executeCommand(Object key){
    commandHistory.push(key);
    commands.get(key).execute();
  }
  
  public void undo(Object key){
      if (commandHistory.isEmpty()){
          return;
      }
      commands.get(commandHistory.pop()).undo();
  }
}