    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.Block;
    018import org.apache.tapestry5.ComponentResources;
    019import org.apache.tapestry5.annotations.InjectContainer;
    020import org.apache.tapestry5.annotations.Parameter;
    021import org.apache.tapestry5.annotations.SupportsInformalParameters;
    022import org.apache.tapestry5.ioc.annotations.Inject;
    023import org.apache.tapestry5.runtime.Component;
    024
    025/**
    026 * A component that does not do any rendering of its own, but will delegate to some other object that can do rendering.
    027 * This other object may be a component or a {@link Block} (among other things).
    028 * <p>
    029 * This component may also be used to create inline components. For each informal parameter the value will be stored as a
    030 * render variable. To create an inline component, create a block
    031 * and use Delegate multiple times in the template to render the block passing parameters to Delegate. In the block body
    032 * reference the render variables using the "var:" binding prefix and the name of the parameter.
    033 * <p>
    034 * Note that the default binding prefix for informal parameter values is "literal".
    035 *
    036 * @tapestrydoc
    037 */
    038@SupportsInformalParameters
    039public class Delegate
    040{
    041    /**
    042     * The object which will be rendered in place of the Delegate component. This is typically a specific component
    043     * instance, or a {@link Block}.
    044     */
    045    @Parameter(required = true)
    046    private Object to;
    047
    048    @Inject private ComponentResources resources;
    049    @InjectContainer private Component container;
    050
    051    Object beginRender()
    052    {
    053        for(String name : resources.getInformalParameterNames()) {
    054            Object value = resources.getInformalParameter(name, Object.class);
    055            container.getComponentResources().storeRenderVariable(name, value);
    056        }
    057
    058        return to;
    059    }
    060}