001 // Copyright 2004, 2005 The Apache Software Foundation 002 // 003 // Licensed under the Apache License, Version 2.0 (the "License"); 004 // you may not use this file except in compliance with the License. 005 // You may obtain a copy of the License at 006 // 007 // http://www.apache.org/licenses/LICENSE-2.0 008 // 009 // Unless required by applicable law or agreed to in writing, software 010 // distributed under the License is distributed on an "AS IS" BASIS, 011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 012 // See the License for the specific language governing permissions and 013 // limitations under the License. 014 015 package org.apache.tapestry.link; 016 017 import org.apache.tapestry.IAction; 018 import org.apache.tapestry.IActionListener; 019 import org.apache.tapestry.IRequestCycle; 020 import org.apache.tapestry.RenderRewoundException; 021 import org.apache.tapestry.Tapestry; 022 import org.apache.tapestry.engine.ActionServiceParameter; 023 import org.apache.tapestry.engine.ILink; 024 import org.apache.tapestry.listener.ListenerInvoker; 025 026 /** 027 * A component for creating a link that is handled using the action service. [ <a 028 * href="../../../../../ComponentReference/ActionLink.html">Component Reference </a>] 029 * 030 * @author Howard Lewis Ship 031 */ 032 033 public abstract class ActionLink extends AbstractLinkComponent implements IAction 034 { 035 public abstract boolean isStateful(); 036 037 /** 038 * Returns true if the stateful parameter is bound to a true value. If stateful is not bound, 039 * also returns the default, true. 040 * <p> 041 * Note that this method can be called when the component is not rendering, therefore it must 042 * directly access the {@link IBinding}for the stateful parameter. 043 */ 044 045 public boolean getRequiresSession() 046 { 047 return isStateful(); 048 } 049 050 public ILink getLink(IRequestCycle cycle) 051 { 052 String actionId = cycle.getNextActionId(); 053 054 if (cycle.isRewound(this)) 055 { 056 getListenerInvoker().invokeListener(getListener(), this, cycle); 057 058 throw new RenderRewoundException(this); 059 } 060 061 return getLink(cycle, Tapestry.ACTION_SERVICE, new ActionServiceParameter(this, actionId)); 062 } 063 064 public abstract IActionListener getListener(); 065 066 public abstract ListenerInvoker getListenerInvoker(); 067 }