// Copyright 2004, 2005 The Apache Software Foundation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package org.apache.tapestry.link;
import java.util.List;
import org.apache.tapestry.IActionListener;
import org.apache.tapestry.IDirect;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.engine.DirectServiceParameter;
import org.apache.tapestry.engine.IEngineService;
import org.apache.tapestry.engine.ILink;
import org.apache.tapestry.listener.ListenerInvoker;
/**
* A component for creating a link using the direct service; used for actions that are not dependant
* on dynamic page state. [ <a href="../../../../../ComponentReference/DirectLink.html">Component
* Reference </a>]
*
* @author Howard Lewis Ship
*/
public abstract class DirectLink extends AbstractLinkComponent implements IDirect
{
public abstract IActionListener getListener();
/**
* Returns true if the stateful parameter is bound to a true value. If stateful is not bound,
* also returns the default, true.
*/
public abstract boolean isStateful();
public ILink getLink(IRequestCycle cycle)
{
Object[] serviceParameters = constructServiceParameters(getParameters());
DirectServiceParameter dsp = new DirectServiceParameter(this, serviceParameters);
return getEngine().getLink(isStateful(), dsp);
}
/**
* Converts a service parameters value to an array of objects. This is used by the
* {@link DirectLink},{@link ServiceLink}and {@link ExternalLink}components.
*
* @param parameterValue
* the input value which may be
* <ul>
* <li>null (returns null)
* <li>An array of Object (returns the array)
* <li>A {@link List}(returns an array of the values in the List})
* <li>A single object (returns the object as a single-element array)
* </ul>
* @return An array representation of the input object.
* @since 2.2
*/
public static Object[] constructServiceParameters(Object parameterValue)
{
if (parameterValue == null)
return null;
if (parameterValue instanceof Object[])
return (Object[]) parameterValue;
if (parameterValue instanceof List)
{
List list = (List) parameterValue;
return list.toArray();
}
return new Object[] { parameterValue };
}
/**
* Invoked by the direct service to trigger the application-specific action by notifying the
* {@link IActionListener listener}.
*
* @throws org.apache.tapestry.StaleSessionException
* if the component is stateful, and the session is new.
*/
public void trigger(IRequestCycle cycle)
{
IActionListener listener = getListener();
if (listener == null)
throw Tapestry.createRequiredParameterException(this, "listener");
getListenerInvoker().invokeListener(listener, this, cycle);
}
/** @since 2.2 * */
public abstract Object getParameters();
/**
* Injected.
*
* @since 4.0
*/
public abstract ListenerInvoker getListenerInvoker();
/**
* Injected.
*
* @since 4.1
*/
public abstract IEngineService getEngine();
}