| /* |
| * $Id$ |
| * |
| * 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.template; |
| |
| import java.util.Deque; |
| import java.util.LinkedList; |
| import java.util.Map; |
| |
| import org.apache.tiles.request.Request; |
| |
| /** |
| * Utilities to work with compose stacks. |
| * |
| * @version $Rev$ $Date$ |
| * @since 3.0.0 |
| */ |
| public final class ComposeStackUtil { |
| |
| /** |
| * The name of the attribute that holds the compose stack. |
| */ |
| public static final String COMPOSE_STACK_ATTRIBUTE_NAME = "org.apache.tiles.template.COMPOSE_STACK"; |
| |
| /** |
| * Private constructor to avoid instantiation. |
| */ |
| private ComposeStackUtil() { |
| |
| } |
| |
| /** |
| * Finds the first ancestor in the stack, that is assignable to the given class. |
| * |
| * @param composeStack The compose stack to evaluate. |
| * @param clazz The class to check. |
| * @return The first ancestor that is assignable to the class, or null if not found. |
| * @since 3.0.0 |
| */ |
| public static Object findAncestorWithClass(Deque<Object> composeStack, Class<?> clazz) { |
| for (Object obj : composeStack) { |
| if (clazz.isAssignableFrom(obj.getClass())) { |
| return obj; |
| } |
| } |
| |
| return null; |
| } |
| |
| /** |
| * Returns the current compose stack, or creates a new one if not present. |
| * |
| * @param request The request. |
| * @return The compose stack. |
| * @since 3.0.0 |
| */ |
| @SuppressWarnings("unchecked") |
| public static Deque<Object> getComposeStack(Request request) { |
| Map<String, Object> requestScope = request.getContext("request"); |
| Deque<Object> composeStack = (Deque<Object>) requestScope |
| .get(COMPOSE_STACK_ATTRIBUTE_NAME); |
| if (composeStack == null) { |
| composeStack = new LinkedList<Object>(); |
| requestScope.put(ComposeStackUtil.COMPOSE_STACK_ATTRIBUTE_NAME, composeStack); |
| } |
| return composeStack; |
| } |
| } |