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
015package org.apache.tapestry.callback;
016
017import org.apache.hivemind.ApplicationRuntimeException;
018import org.apache.hivemind.util.Defense;
019import org.apache.tapestry.IComponent;
020import org.apache.tapestry.IDirect;
021import org.apache.tapestry.IPage;
022import org.apache.tapestry.IRequestCycle;
023
024/**
025 * Simple callback for re-invoking a {@link IDirect} trigger.
026 * 
027 * @author Howard Lewis Ship
028 * @since 0.2.9
029 */
030
031public class DirectCallback implements ICallback
032{
033    /**
034     * @since 2.0.4
035     */
036
037    private static final long serialVersionUID = -8888847655917503471L;
038
039    private String _pageName;
040
041    private String _componentIdPath;
042
043    private Object[] _parameters;
044
045    public String toString()
046    {
047        StringBuffer buffer = new StringBuffer("DirectCallback[");
048
049        buffer.append(_pageName);
050        buffer.append('/');
051        buffer.append(_componentIdPath);
052
053        if (_parameters != null)
054        {
055            for (int i = 0; i < _parameters.length; i++)
056            {
057                buffer.append(i == 0 ? " " : ", ");
058                buffer.append(_parameters[i]);
059            }
060        }
061
062        buffer.append(']');
063
064        return buffer.toString();
065
066    }
067
068    /**
069     * Creates a new DirectCallback for the component. The parameters (which may be null) is
070     * retained, not copied.
071     */
072
073    public DirectCallback(IDirect component, Object[] parameters)
074    {
075        Defense.notNull(component, "component");
076
077        _pageName = component.getPage().getPageName();
078        _componentIdPath = component.getIdPath();
079        _parameters = parameters;
080    }
081
082    /**
083     * Locates the {@link IDirect}component that was previously identified (and whose page and id
084     * path were stored). Invokes {@link IRequestCycle#setListenerParameters(Object[])(Object[])}to
085     * restore the service parameters, then invokes {@link IDirect#trigger(IRequestCycle)}on the
086     * component.
087     */
088
089    public void performCallback(IRequestCycle cycle)
090    {
091        IPage page = cycle.getPage(_pageName);
092        IComponent component = page.getNestedComponent(_componentIdPath);
093        IDirect direct = null;
094
095        try
096        {
097            direct = (IDirect) component;
098        }
099        catch (ClassCastException ex)
100        {
101            throw new ApplicationRuntimeException(CallbackMessages.componentNotDirect(component),
102                    component, null, ex);
103        }
104
105        cycle.setListenerParameters(_parameters);
106        direct.trigger(cycle);
107    }
108}