org.springframework.core.codec.AbstractDataBufferDecoder Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or authors.
*
* 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
*
* https://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.springframework.core.codec;
import java.util.Map;
import org.reactivestreams.Publisher;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;
import org.springframework.core.ResolvableType;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.MimeType;
/**
* Abstract base class for {@code Decoder} implementations that can decode
* a {@code DataBuffer} directly to the target element type.
*
* Sub-classes must implement {@link #decodeDataBuffer} to provide a way to
* transform a {@code DataBuffer} to the target data type. The default
* {@link #decode} implementation transforms each individual data buffer while
* {@link #decodeToMono} applies "reduce" and transforms the aggregated buffer.
*
*
Sub-classes can override {@link #decode} in order to split the input stream
* along different boundaries (e.g. on new line characters for {@code String})
* or always reduce to a single data buffer (e.g. {@code Resource}).
*
* @author Rossen Stoyanchev
* @since 5.0
* @param the element type
*/
public abstract class AbstractDataBufferDecoder extends AbstractDecoder {
protected AbstractDataBufferDecoder(MimeType... supportedMimeTypes) {
super(supportedMimeTypes);
}
@Override
public Flux decode(Publisher inputStream, ResolvableType elementType,
@Nullable MimeType mimeType, @Nullable Map hints) {
return Flux.from(inputStream).map(buffer -> decodeDataBuffer(buffer, elementType, mimeType, hints));
}
@Override
public Mono decodeToMono(Publisher inputStream, ResolvableType elementType,
@Nullable MimeType mimeType, @Nullable Map hints) {
return DataBufferUtils.join(inputStream)
.map(buffer -> decodeDataBuffer(buffer, elementType, mimeType, hints));
}
/**
* How to decode a {@code DataBuffer} to the target element type.
*/
protected abstract T decodeDataBuffer(DataBuffer buffer, ResolvableType elementType,
@Nullable MimeType mimeType, @Nullable Map hints);
}