001// Copyright 2007, 2008, 2011 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.tapestry5.corelib.components;
016
017import org.apache.tapestry5.BindingConstants;
018import org.apache.tapestry5.ComponentResources;
019import org.apache.tapestry5.Link;
020import org.apache.tapestry5.MarkupWriter;
021import org.apache.tapestry5.annotations.Parameter;
022import org.apache.tapestry5.corelib.base.AbstractLink;
023import org.apache.tapestry5.ioc.annotations.Inject;
024
025/**
026 * Generates a render request link to some other page in the application. If an activation context is supplied (as the
027 * context parameter), then the context values will be encoded into the URL. If no context is supplied, then the target
028 * page itself will supply the context via a passivate event.
029 * <p/>
030 * Pages are not required to have an activation context. When a page does have an activation context, the value
031 * typically represents the identity of some object displayed or otherwise manipulated by the page.
032 * 
033 * @tapestrydoc
034 */
035public class PageLink extends AbstractLink
036{
037    /**
038     * The logical name of the page to link to.
039     */
040    @Parameter(required = true, allowNull = false, defaultPrefix = BindingConstants.LITERAL)
041    private String page;
042
043    @Inject
044    private ComponentResources resources;
045
046    /**
047     * If provided, this is the activation context for the target page (the information will be encoded into the URL).
048     * If not provided, then the target page will provide its own activation context.
049     */
050    @Parameter
051    private Object[] context;
052
053    void beginRender(MarkupWriter writer)
054    {
055        if (isDisabled()) return;
056
057        Link link = resources.createPageLink(page, resources.isBound("context"), context);
058
059        writeLink(writer, link);
060    }
061
062    void afterRender(MarkupWriter writer)
063    {
064        if (isDisabled()) return;
065
066        writer.end(); // <a>
067    }
068}