001/*
002 * Copyright 2002-2018 the original author or authors.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *      https://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016
017package org.springframework.core.io.buffer;
018
019/**
020 * Extension of {@link DataBuffer} that allows for buffer that share
021 * a memory pool. Introduces methods for reference counting.
022 *
023 * @author Arjen Poutsma
024 * @since 5.0
025 */
026public interface PooledDataBuffer extends DataBuffer {
027
028        /**
029         * Return {@code true} if this buffer is allocated;
030         * {@code false} if it has been deallocated.
031         * @since 5.1
032         */
033        boolean isAllocated();
034
035        /**
036         * Increase the reference count for this buffer by one.
037         * @return this buffer
038         */
039        PooledDataBuffer retain();
040
041        /**
042         * Decrease the reference count for this buffer by one,
043         * and deallocate it once the count reaches zero.
044         * @return {@code true} if the buffer was deallocated;
045         * {@code false} otherwise
046         */
047        boolean release();
048
049}