actionmethodmapper.java

Novocode的 SWT 控件框架 丰富了MDI功能

/*******************************************************************************
 * Copyright (c) 2004 Stefan Zeiger and others.
 * All rights reserved. This program and the accompanying materials 
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.novocode.com/legal/epl-v10.html
 * 
 * Contributors:
 *     Stefan Zeiger ([e-mail]) - initial API and implementation
 *******************************************************************************/

package com.novocode.naf.gui.event;

import java.lang.reflect.Method;

import com.novocode.naf.app.NAFException;
import com.novocode.naf.model.ModelMap;


/**
 * Utility class which created ActionListeners that invoke methods of an
 * object which are marked with an ActionMethod annotation.
 *
 * @author Stefan Zeiger ([e-mail])
 * @since Dec 19, 2004
 * @version $Id: ActionMethodMapper.java,v 1.2 2005/01/14 21:14:48 szeiger Exp $
 */

public class ActionMethodMapper
{
  private static final Object[] EMPTY_OBJECT_ARRAY = new Object[0];
  
  
  private ActionMethodMapper() {}
  
  
  public static void createModels(Object target, ModelMap models) throws NAFException
  {
    createModels(target, target.getClass(), models);
  }

    
  public static void createModels(Class clazz, ModelMap models) throws NAFException
  {
    createModels(null, clazz, models);
  }

    
  private static void createModels(final Object target, Class clazz, ModelMap models) throws NAFException
  {
    for(final Method method : clazz.getMethods())
    {
      ActionMethod am = method.getAnnotation(ActionMethod.class);
      if(am == null) continue;
      IActionListener al = actionListenerFor(target, clazz, method);
      String modelName = am.value();
      if(modelName == null || modelName.length() == 0) modelName = method.getName();
      Object old = models.get(modelName);
      if(old == null) models.put(modelName, al);
      else if(old instanceof IActionBroadcaster) ((IActionBroadcaster)old).addActionListener(al);
      else if(old instanceof IActionListener)
      {
        DefaultActionBroadcaster bc = new DefaultActionBroadcaster();
        bc.addActionListener((IActionListener)old);
        bc.addActionListener(al);
        models.put(modelName, bc);
      }
      else throw new NAFException("Model "+modelName+" already has a non-IActionListener object attached");
    }
  }
  
  
  public static final IActionListener actionListenerFor(final Object target, Class clazz, final Method method) throws NAFException
  {
    final String qname = clazz.getName()+"."+method.getName();
    Class[] paramTypes = method.getParameterTypes();
    if(paramTypes.length == 0)
    {
      return new IActionListener()
      {
        public void performAction(ActionEvent e)
        {
          try { method.invoke(target, EMPTY_OBJECT_ARRAY); }
          catch(Exception ex) { throw new NAFException("Error invoking method "+qname, ex); }
        }
      };
    }
    else if(paramTypes.length == 1 && paramTypes[0] == ActionEvent.class)
    {
      return new IActionListener()
      {
        public void performAction(ActionEvent e)
        {
          try { method.invoke(target, new Object[] { e }); }
          catch(Exception ex) { throw new NAFException("Error invoking method "+qname, ex); }
        }
      };
    }
    else throw new NAFException("ActionMethod "+qname+" must have a signature () or (ActionEvent)");
  }
}