com.hazelcast.util.Clock Maven / Gradle / Ivy
/*
* Copyright (c) 2008-2013, Hazelcast, Inc. All Rights Reserved.
*
* 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 com.hazelcast.util;
/**
* Utility class to be able to simulate different time zones.
* Time offset can be configured with following property
* "com.hazelcast.clock.offset"
*/
public final class Clock {
private static final ClockImpl CLOCK;
private Clock() {
}
public static long currentTimeMillis() {
return CLOCK.currentTimeMillis();
}
static {
final String clockOffset = System.getProperty("com.hazelcast.clock.offset");
long offset = 0L;
if (clockOffset != null) {
try {
offset = Long.parseLong(clockOffset);
} catch (NumberFormatException ignored) {
EmptyStatement.ignore(ignored);
}
}
if (offset == 0L) {
CLOCK = new SystemClock();
} else {
CLOCK = new SystemOffsetClock(offset);
}
}
private abstract static class ClockImpl {
protected abstract long currentTimeMillis();
}
private static final class SystemClock extends ClockImpl {
@Override
protected long currentTimeMillis() {
return System.currentTimeMillis();
}
@Override
public String toString() {
return "SystemClock";
}
}
private static final class SystemOffsetClock extends ClockImpl {
private final long offset;
private SystemOffsetClock(final long offset) {
this.offset = offset;
}
@Override
protected long currentTimeMillis() {
return System.currentTimeMillis() + offset;
}
@Override
public String toString() {
final StringBuilder sb = new StringBuilder();
sb.append("SystemOffsetClock");
sb.append("{offset=").append(offset);
sb.append('}');
return sb.toString();
}
}
}