/*
* 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.tomcat.util.http;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.Queue;
import java.util.TimeZone;
import java.util.concurrent.ConcurrentLinkedQueue;
/**
* A thread safe wrapper around {@link SimpleDateFormat} that does not make use of ThreadLocal and - broadly - only
* creates enough SimpleDateFormat objects to satisfy the concurrency requirements.
*/
public class ConcurrentDateFormat {
private final String format;
private final Locale locale;
private final TimeZone timezone;
private final Queue<SimpleDateFormat> queue = new ConcurrentLinkedQueue<>();
public ConcurrentDateFormat(String format, Locale locale, TimeZone timezone) {
this.format = format;
this.locale = locale;
this.timezone = timezone;
SimpleDateFormat initial = createInstance();
queue.add(initial);
}
public String format(Date date) {
SimpleDateFormat sdf = queue.poll();
if (sdf == null) {
sdf = createInstance();
}
String result = sdf.format(date);
queue.add(sdf);
return result;
}
public Date parse(String source) throws ParseException {
SimpleDateFormat sdf = queue.poll();
if (sdf == null) {
sdf = createInstance();
}
Date result = sdf.parse(source);
sdf.setTimeZone(timezone);
queue.add(sdf);
return result;
}
private SimpleDateFormat createInstance() {
SimpleDateFormat sdf = new SimpleDateFormat(format, locale);
sdf.setTimeZone(timezone);
return sdf;
}
}