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/**
* 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 net.logstash.logback.marker;
import java.text.MessageFormat;
import java.util.HashMap;
import java.util.Map;
/**
* A cache for {@link MessageFormat} objects.
*
*
* Since only a small subset of {@link MessageFormat}s are generally used by
* {@link SingleFieldAppendingMarker}, the {@link MessageFormatCache} will
* cache them (per thread) so that they can be reused.
*
*
* This is a performance optimization to save {@link MessageFormat} construction and parsing time
* for each argument/marker.
*
*/
public class MessageFormatCache {
public static final MessageFormatCache INSTANCE = new MessageFormatCache();
/**
* Use a {@link ThreadLocal} cache, since {@link MessageFormat}s are not threadsafe.
*/
private ThreadLocal> messageFormats = new ThreadLocal>() {
protected Map initialValue() {
return new HashMap();
};
};
public MessageFormat getMessageFormat(String formatPattern) {
Map messageFormatsForCurrentThread = messageFormats.get();
MessageFormat messageFormat = messageFormatsForCurrentThread.get(formatPattern);
if (messageFormat == null) {
messageFormat = new MessageFormat(formatPattern);
messageFormatsForCurrentThread.put(formatPattern, messageFormat);
}
return messageFormat;
}
}