org.apache.maven.scm.util.ThreadSafeDateFormat Maven / Gradle / Ivy

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package org.apache.maven.scm.util;

/*
 * 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.
 */

import java.lang.ref.SoftReference;
import java.text.DateFormat;
import java.text.FieldPosition;
import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * Thread-safe version of java.text.DateFormat.
 * You can declare it as a static final variable:
 * @author Olivier Lamy
 * 
 * private static final ThreadSafeDateFormat DATE_FORMAT = new ThreadSafeDateFormat( DATE_PATTERN );
 * 
 */
public class ThreadSafeDateFormat extends DateFormat
{
    private static final long serialVersionUID = 3786090697869963812L;

    private final String m_sDateFormat;

    public ThreadSafeDateFormat(String sDateFormat)
    {
        m_sDateFormat = sDateFormat;
    }

    private final ThreadLocal> m_formatCache = new ThreadLocal>()
    {
        public SoftReference get()
        {
            SoftReference softRef = super.get();
            if (softRef == null || softRef.get() == null)
            {
                softRef = new SoftReference( new SimpleDateFormat(m_sDateFormat) );
                super.set(softRef);
            }
            return softRef;
        }
    };

    private DateFormat getDateFormat()
    {
        return m_formatCache.get().get();
    }

    public StringBuffer format(Date date, StringBuffer toAppendTo,
            FieldPosition fieldPosition)
    {
        return getDateFormat().format(date, toAppendTo, fieldPosition);
    }

    public Date parse(String source, ParsePosition pos)
    {
        return getDateFormat().parse(source, pos);
    }
}