/*
* Licensed to the Apache Software Foundation (ASF) under one or more contributor license
* agreements. See the NOTICE file distributed with this work for additional information regarding
* copyright ownership. The ASF licenses this file to You 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.apache.geode.rest.internal.web.http.converter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.concurrent.atomic.AtomicLong;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpOutputMessage;
import org.springframework.http.converter.HttpMessageNotWritableException;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.util.Assert;
/**
* The CustomMappingJackson2HttpMessageConverter class...
*
* @see org.springframework.http.converter.json.MappingJackson2HttpMessageConverter
* @since GemFire 0.0.1
*/
@SuppressWarnings("unused")
public class CustomMappingJackson2HttpMessageConverter extends MappingJackson2HttpMessageConverter {
protected static final int INITIAL_BYTE_ARRAY_BUFFER_SIZE = 8192;
@Override
protected void writeInternal(final Object object, final HttpOutputMessage outputMessage)
throws IOException, HttpMessageNotWritableException {
HttpOutputMessageWrapper outputMessageWrapper =
new BufferingHttpOutputMessageWrapper(outputMessage);
super.writeInternal(object, outputMessageWrapper);
outputMessageWrapper.flush();
}
protected static final class BufferingHttpOutputMessageWrapper
implements HttpOutputMessageWrapper {
private final ByteArrayOutputStream outputStream;
private final HttpOutputMessage httpOutputMessage;
protected BufferingHttpOutputMessageWrapper(final HttpOutputMessage httpOutputMessage) {
Assert.notNull(httpOutputMessage, "The HttpOutputMessage instance to wrap must not be null!");
this.httpOutputMessage = httpOutputMessage;
this.outputStream = new ByteArrayOutputStream(INITIAL_BYTE_ARRAY_BUFFER_SIZE);
}
@Override
public OutputStream getBody() throws IOException {
return outputStream;
}
public long getContentLength() {
return outputStream.size();
}
@Override
public HttpHeaders getHeaders() {
return httpOutputMessage.getHeaders();
}
public void flush() throws IOException {
getHeaders().setContentLength(getContentLength());
outputStream.writeTo(httpOutputMessage.getBody());
outputStream.reset();
}
}
/**
* While sound idea in theory to "count the bytes as you stream/write", thus preserving memory,
* this does not work in practice since the HTTP headers must be written to the HTTP output stream
* response before the body!
*/
protected static class ContentLengthAccessibleHttpOutputMessageWrapper
implements HttpOutputMessageWrapper {
private final ByteCountingOutputStream outputStream;
private final HttpOutputMessage httpOutputMessage;
protected ContentLengthAccessibleHttpOutputMessageWrapper(
final HttpOutputMessage httpOutputMessage) throws IOException {
Assert.notNull(httpOutputMessage, "The HttpOutputMessage instance to wrap must not be null!");
this.httpOutputMessage = httpOutputMessage;
this.outputStream = new ByteCountingOutputStream(this.httpOutputMessage.getBody());
}
@Override
public OutputStream getBody() throws IOException {
return outputStream;
}
public long getContentLength() {
return outputStream.getByteCount();
}
@Override
public HttpHeaders getHeaders() {
return httpOutputMessage.getHeaders();
}
public void flush() throws IOException {
getHeaders().setContentLength(getContentLength());
}
}
protected interface HttpOutputMessageWrapper extends HttpOutputMessage {
public long getContentLength();
public void flush() throws IOException;
}
protected static final class ByteCountingOutputStream extends OutputStream {
private AtomicLong byteCount = new AtomicLong(0l);
private final OutputStream outputStream;
protected ByteCountingOutputStream(final OutputStream outputStream) {
Assert.notNull(outputStream, "The OutputStream to wrap must not be null!");
this.outputStream = outputStream;
}
protected long getByteCount() {
return byteCount.get();
}
@Override
public void write(final int byteData) throws IOException {
outputStream.write(byteData);
byteCount.incrementAndGet();
}
}
}