/* ====================================================================
* The Apache Software License, Version 1.1
*
* Copyright (c) 2000-2003 The Apache Software Foundation. All rights
* reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* 3. The end-user documentation included with the redistribution,
* if any, must include the following acknowledgment:
* "This product includes software developed by the
* Apache Software Foundation (http://apache.org/)."
* Alternately, this acknowledgment may appear in the software itself,
* if and wherever such third-party acknowledgments normally appear.
*
* 4. The names "Apache" and "Apache Software Foundation", "Tapestry"
* must not be used to endorse or promote products derived from this
* software without prior written permission. For written
* permission, please contact apache@apache.org.
*
* 5. Products derived from this software may not be called "Apache"
* or "Tapestry", nor may "Apache" or "Tapestry" appear in their
* name, without prior written permission of the Apache Software Foundation.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE TAPESTRY CONTRIBUTOR COMMUNITY
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
* ====================================================================
*
* This software consists of voluntary contributions made by many
* individuals on behalf of the Apache Software Foundation. For more
* information on the Apache Software Foundation, please see
* <http://www.apache.org/>.
*
*/
package org.apache.tapestry.link;
import java.util.List;
import org.apache.tapestry.IActionListener;
import org.apache.tapestry.IBinding;
import org.apache.tapestry.IDirect;
import org.apache.tapestry.IRequestCycle;
import org.apache.tapestry.Tapestry;
import org.apache.tapestry.engine.ILink;
/**
* 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
* @version $Id: DirectLink.java,v 1.3 2003/03/23 23:18:29 hlship Exp $
*
**/
public abstract class DirectLink extends AbstractLinkComponent implements IDirect
{
public abstract IBinding getStatefulBinding();
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. May be invoked when not renderring.
*
**/
public boolean isStateful()
{
IBinding statefulBinding = getStatefulBinding();
if (statefulBinding == null)
return true;
return statefulBinding.getBoolean();
}
public ILink getLink(IRequestCycle cycle)
{
return getLink(cycle, Tapestry.DIRECT_SERVICE, constructServiceParameters(getParameters()));
}
/**
* 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 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");
listener.actionTriggered(this, cycle);
}
/** @since 2.2 **/
public abstract Object getParameters();
}