001 // Copyright 2006, 2009, 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. 014 015 package org.apache.tapestry5.ioc.util; 016 017 import org.apache.tapestry5.ioc.MessageFormatter; 018 import org.apache.tapestry5.ioc.Messages; 019 import org.apache.tapestry5.ioc.internal.util.CollectionFactory; 020 import org.apache.tapestry5.ioc.internal.util.MessageFormatterImpl; 021 022 import java.util.Locale; 023 import java.util.Map; 024 025 /** 026 * Abstract implementation of {@link Messages} that doesn't know where values come from (that information is supplied in 027 * a subclass, via the {@link #valueForKey(String)} method). 028 */ 029 public abstract class AbstractMessages implements Messages 030 { 031 /** 032 * String key to MF instance. 033 */ 034 private final Map<String, MessageFormatter> cache = CollectionFactory.newConcurrentMap(); 035 036 private final Locale locale; 037 038 protected AbstractMessages(Locale locale) 039 { 040 this.locale = locale; 041 } 042 043 /** 044 * Invoked to provide the value for a particular key. This may be invoked multiple times even for the same key. The 045 * implementation should <em>ignore the case of the key</em>. 046 * 047 * @param key the key to obtain a value for (case insensitive) 048 * @return the value for the key, or null if this instance can not provide the value 049 */ 050 protected abstract String valueForKey(String key); 051 052 053 public boolean contains(String key) 054 { 055 return valueForKey(key) != null; 056 } 057 058 public String get(String key) 059 { 060 if (contains(key)) return valueForKey(key); 061 062 return String.format("[[missing key: %s]]", key); 063 } 064 065 public MessageFormatter getFormatter(String key) 066 { 067 MessageFormatter result = cache.get(key); 068 069 if (result == null) 070 { 071 result = buildMessageFormatter(key); 072 cache.put(key, result); 073 } 074 075 return result; 076 } 077 078 private MessageFormatter buildMessageFormatter(String key) 079 { 080 String format = get(key); 081 082 return new MessageFormatterImpl(format, locale); 083 } 084 085 public String format(String key, Object... args) 086 { 087 return getFormatter(key).format(args); 088 } 089 090 }