001/* 002 * Copyright 2002-2019 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.codec; 018 019import java.util.Map; 020 021import org.reactivestreams.Publisher; 022import reactor.core.publisher.Flux; 023 024import org.springframework.core.ResolvableType; 025import org.springframework.core.io.buffer.DataBuffer; 026import org.springframework.lang.Nullable; 027import org.springframework.util.MimeType; 028import org.springframework.util.MimeTypeUtils; 029 030/** 031 * Simple pass-through decoder for {@link DataBuffer DataBuffers}. 032 * 033 * <p><strong>Note:</strong> The data buffers should be released via 034 * {@link org.springframework.core.io.buffer.DataBufferUtils#release(DataBuffer)} 035 * after they have been consumed. In addition, if using {@code Flux} or 036 * {@code Mono} operators such as flatMap, reduce, and others that prefetch, 037 * cache, and skip or filter out data items internally, please add 038 * {@code doOnDiscard(PooledDataBuffer.class, DataBufferUtils::release)} to the 039 * composition chain to ensure cached data buffers are released prior to an 040 * error or cancellation signal. 041 * 042 * @author Arjen Poutsma 043 * @author Rossen Stoyanchev 044 * @since 5.0 045 */ 046public class DataBufferDecoder extends AbstractDataBufferDecoder<DataBuffer> { 047 048 public DataBufferDecoder() { 049 super(MimeTypeUtils.ALL); 050 } 051 052 053 @Override 054 public boolean canDecode(ResolvableType elementType, @Nullable MimeType mimeType) { 055 return (DataBuffer.class.isAssignableFrom(elementType.toClass()) && 056 super.canDecode(elementType, mimeType)); 057 } 058 059 @Override 060 public Flux<DataBuffer> decode(Publisher<DataBuffer> input, ResolvableType elementType, 061 @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) { 062 063 return Flux.from(input); 064 } 065 066 @Override 067 public DataBuffer decode(DataBuffer buffer, ResolvableType elementType, 068 @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) { 069 070 if (logger.isDebugEnabled()) { 071 logger.debug(Hints.getLogPrefix(hints) + "Read " + buffer.readableByteCount() + " bytes"); 072 } 073 return buffer; 074 } 075 076}