org.sonar.api.utils.internal.AlwaysIncreasingSystem2 Maven / Gradle / Ivy
/*
* SonarQube
* Copyright (C) 2009-2017 SonarSource SA
* mailto:info AT sonarsource DOT com
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 3 of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
package org.sonar.api.utils.internal;
import java.util.Random;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Supplier;
import org.sonar.api.utils.System2;
import static com.google.common.base.Preconditions.checkArgument;
/**
* A subclass of {@link System2} which implementation of {@link System2#now()} always return a bigger value than the
* previous returned value.
*
* This class is intended to be used in Unit tests.
*
*/
public class AlwaysIncreasingSystem2 extends System2 {
private final AtomicLong now;
private final long increment;
private AlwaysIncreasingSystem2(Supplier initialValueSupplier, long increment) {
checkArgument(increment > 0, "increment must be > 0");
long initialValue = initialValueSupplier.get();
checkArgument(initialValue >= 0, "Initial value must be >= 0");
this.now = new AtomicLong(initialValue);
this.increment = increment;
}
public AlwaysIncreasingSystem2(long increment) {
this(AlwaysIncreasingSystem2::randomInitialValue, increment);
}
public AlwaysIncreasingSystem2(long initialValue, int increment) {
this(() -> initialValue, increment);
}
/**
* Values returned by {@link #now()} will start with a random value and increment by 100.
*/
public AlwaysIncreasingSystem2() {
this(AlwaysIncreasingSystem2::randomInitialValue, 100);
}
@Override
public long now() {
return now.getAndAdd(increment);
}
private static long randomInitialValue() {
return (long) Math.abs(new Random().nextInt(2_000_000));
}
}