| // Copyright 2004 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.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 $Id$ |
| * |
| **/ |
| |
| 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 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"); |
| |
| listener.actionTriggered(this, cycle); |
| } |
| |
| /** @since 2.2 **/ |
| |
| public abstract Object getParameters(); |
| } |