/*
* Copyright 2016 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
*
* 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.springframework.integration.transformer;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.InputStream;
import org.springframework.integration.IntegrationMessageHeaderAccessor;
import org.springframework.messaging.Message;
import org.springframework.util.Assert;
import org.springframework.util.FileCopyUtils;
/**
* Transforms an InputStream payload to a byte[] or String (if a
* charset is provided).
*
* @author Gary Russell
* @since 4.3
*
*/
public class StreamTransformer extends AbstractTransformer {
private final String charset;
/**
* Construct an instance to transform an {@link InputStream} to
* a {@code byte[]}.
*/
public StreamTransformer() {
this(null);
}
/**
* Construct an instance with the charset to convert the stream to a
* String; if null a {@code byte[]} will be produced instead.
* @param charset the charset.
*/
public StreamTransformer(String charset) {
this.charset = charset;
}
@Override
protected Object doTransform(Message<?> message) throws Exception {
Assert.isTrue(message.getPayload() instanceof InputStream, "payload must be an InputStream");
InputStream stream = (InputStream) message.getPayload();
ByteArrayOutputStream baos = new ByteArrayOutputStream();
FileCopyUtils.copy(stream, baos);
Closeable closeableResource = new IntegrationMessageHeaderAccessor(message).getCloseableResource();
if (closeableResource != null) {
closeableResource.close();
}
return this.charset == null ? baos.toByteArray() : baos.toString(this.charset);
}
}