org.apache.logging.log4j.util.LazyBoolean Maven / Gradle / Ivy
/*
* 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.logging.log4j.util;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.function.BooleanSupplier;
public class LazyBoolean implements BooleanSupplier {
private final BooleanSupplier supplier;
private final Lock lock = new ReentrantLock();
private volatile boolean initialized;
private volatile boolean value;
public LazyBoolean(final BooleanSupplier supplier) {
this.supplier = supplier;
}
@Override
public boolean getAsBoolean() {
boolean uninitialized = !initialized;
boolean value = this.value;
if (uninitialized) {
lock.lock();
try {
uninitialized = !initialized;
if (uninitialized) {
this.value = value = supplier.getAsBoolean();
initialized = true;
}
} finally {
lock.unlock();
}
}
return value;
}
public void setAsBoolean(final boolean b) {
lock.lock();
try {
initialized = false;
value = b;
initialized = true;
} finally {
lock.unlock();
}
}
public void reset() {
initialized = false;
}
}