org.apache.tiles.request.render.ChainedDelegateRenderer Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.tiles.request.render;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import org.apache.tiles.request.Request;
/**
* Renders an attribute that has no associated renderer using delegation to other renderers.
*/
public class ChainedDelegateRenderer implements Renderer {
/**
* The list of chained renderers.
*/
private final List renderers;
/**
* Constructor.
*/
public ChainedDelegateRenderer() {
renderers = new ArrayList<>();
}
/**
* Adds an attribute renderer to the list. The first inserted this way, the
* first is checked when rendering.
*
* @param renderer The renderer to add.
*/
public void addAttributeRenderer(Renderer renderer) {
renderers.add(renderer);
}
@Override
public void render(String value, Request request) throws IOException {
if (value == null) {
throw new NullPointerException("The attribute value is null");
}
for (Renderer renderer : renderers) {
if (renderer.isRenderable(value, request)) {
renderer.render(value, request);
return;
}
}
throw new CannotRenderException("Cannot renderer value '" + value + "'");
}
/** {@inheritDoc} */
public boolean isRenderable(String value, Request request) {
for (Renderer renderer : renderers) {
if (renderer.isRenderable(value, request)) {
return true;
}
}
return false;
}
}