// Copyright 2006 The Apache Software Foundation
//
// Licensed 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.tapestry.ioc.util;
import org.apache.tapestry.ioc.MessageFormatter;
import org.apache.tapestry.ioc.Messages;
import static org.apache.tapestry.ioc.internal.util.CollectionFactory.newCaseInsensitiveMap;
import org.apache.tapestry.ioc.internal.util.ConcurrentBarrier;
import org.apache.tapestry.ioc.internal.util.Invokable;
import org.apache.tapestry.ioc.internal.util.MessageFormatterImpl;
import java.util.Locale;
import java.util.Map;
/**
* Abstract implementation of {@link Messages} that doesn't know where values come from (that
* information is supplied in a subclass, via the {@link #valueForKey(String)} method).
*/
public abstract class AbstractMessages implements Messages
{
private final ConcurrentBarrier _barrier = new ConcurrentBarrier();
/**
* String key to MF instance.
*/
private final Map<String, MessageFormatter> _cache = newCaseInsensitiveMap();
private final Locale _locale;
protected AbstractMessages(Locale locale)
{
_locale = locale;
}
/**
* Invoked to provide the value for a particular key. This may be invoked multiple times even
* for the same key. The implementation should <em>ignore the case of the key</em>.
*
* @param key the key to obtain a value for (case insensitive)
* @return the value for the key, or null if this instance can not provide the value
*/
protected abstract String valueForKey(String key);
public boolean contains(String key)
{
return valueForKey(key) != null;
}
public String get(String key)
{
if (contains(key)) return valueForKey(key);
return String.format("[[missing key: %s]]", key);
}
public MessageFormatter getFormatter(final String key)
{
MessageFormatter result = _barrier.withRead(new Invokable<MessageFormatter>()
{
public MessageFormatter invoke()
{
return _cache.get(key);
}
});
if (result != null) return result;
final MessageFormatter newFormatter = buildMessageFormatter(key);
_barrier.withWrite(new Runnable()
{
public void run()
{
_cache.put(key, newFormatter);
}
});
return newFormatter;
}
private MessageFormatter buildMessageFormatter(String key)
{
String format = get(key);
return new MessageFormatterImpl(format, _locale);
}
public String format(String key, Object... args)
{
return getFormatter(key).format(args);
}
}