001// Copyright 2010 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.internal.services; 016 017import org.apache.tapestry5.ioc.MessageFormatter; 018import org.apache.tapestry5.ioc.Messages; 019 020/** 021 * Implementation of {@link Messages} that wraps two other Messages instances: a primary and a delegate. 022 * The primary handles any keys it contains; method invocations that reference keys not contained by 023 * the primary are passed on to the delegate. 024 * 025 * @since 5.2.0 026 */ 027public class DelegatingMessagesImpl implements Messages 028{ 029 private final Messages primary, delegate; 030 031 public DelegatingMessagesImpl(Messages primary, Messages delegate) 032 { 033 this.primary = primary; 034 this.delegate = delegate; 035 } 036 037 public boolean contains(String key) 038 { 039 return primary.contains(key) || delegate.contains(key); 040 } 041 042 private Messages select(String key) 043 { 044 return primary.contains(key) ? primary : delegate; 045 } 046 047 public String format(String key, Object... args) 048 { 049 return select(key).format(key, args); 050 } 051 052 public String get(String key) 053 { 054 return select(key).get(key); 055 } 056 057 public MessageFormatter getFormatter(String key) 058 { 059 return select(key).getFormatter(key); 060 } 061}