org.apache.openjpa.lib.util.TimestampHelper Maven / Gradle / Ivy
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* 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
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* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.openjpa.lib.util;
import java.sql.Timestamp;
/**
* Helper base class attempts to return java.sql.Timestamp object with
* nanosecond precision.
*
* @author Albert Lee
*/
public class TimestampHelper {
// number of millisecond, mircoseconds and nanoseconds in one second.
protected static final long MilliMuliplier = 1000L;
protected static final long MicroMuliplier = MilliMuliplier * 1000L;
protected static final long NanoMuliplier = MicroMuliplier * 1000L;
// number of seconds passed 1970/1/1 00:00:00 GMT.
private static long sec0;
// fraction of seconds passed 1970/1/1 00:00:00 GMT, offset by
// the base System.nanoTime (nano0), in nanosecond unit.
private static long nano0;
static {
// initialize base time in second and fraction of second (ns).
long curTime = System.currentTimeMillis();
sec0 = curTime / MilliMuliplier;
nano0 = (curTime % MilliMuliplier) * MicroMuliplier - System.nanoTime();
}
/*
* Return a java.sql.Timestamp object of current time.
*/
public static Timestamp getNanoPrecisionTimestamp() {
long nano_delta = nano0 + System.nanoTime();
long sec1 = sec0 + (nano_delta / NanoMuliplier);
long nano1 = nano_delta % NanoMuliplier;
Timestamp rtnTs = new Timestamp(sec1 * MilliMuliplier);
rtnTs.setNanos((int) nano1);
return rtnTs;
}
}