/*
* Copyright 2015 Ben Manes. 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.github.benmanes.caffeine.cache;
import java.util.concurrent.locks.Lock;
import java.util.function.Consumer;
/**
* A skeletal implementation of a read buffer strategy.
*
* @author ben.manes@gmail.com (Ben Manes)
*/
public abstract class ReadBuffer<E> implements Buffer<E> {
public static final int BUFFER_SIZE = 32;
public static final int BUFFER_MASK = BUFFER_SIZE - 1;
final Consumer<E> consumer = any -> {};
final Lock evictionLock = new NonReentrantLock();
/**
* Attempts to record an event.
*
* @return if a drain is needed
*/
public boolean record(E e) {
return offer(e) == Buffer.FULL;
}
/** Drains the events. */
public void drain() {
if (evictionLock.tryLock()) {
try {
drainTo(consumer);
} finally {
evictionLock.unlock();
}
}
}
/** Returns the total number of events recorded. */
public int recorded() {
return writes();
}
/** Returns the total number of events consumed. */
public int drained() {
drain();
return reads();
}
}