/*
* Copyright 2002-2011 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.http.converter.xml;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import javax.xml.transform.TransformerException;
import javax.xml.transform.dom.DOMResult;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamResult;
import javax.xml.transform.stream.StreamSource;
import org.xml.sax.InputSource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.converter.HttpMessageConversionException;
import org.springframework.http.converter.HttpMessageNotReadableException;
import org.springframework.http.converter.HttpMessageNotWritableException;
/**
* Implementation of {@link org.springframework.http.converter.HttpMessageConverter} that can read and write {@link
* Source} objects.
*
* @author Arjen Poutsma
* @since 3.0
*/
public class SourceHttpMessageConverter<T extends Source> extends AbstractXmlHttpMessageConverter<T> {
@Override
public boolean supports(Class<?> clazz) {
return DOMSource.class.equals(clazz) || SAXSource.class.equals(clazz) || StreamSource.class.equals(clazz) ||
Source.class.equals(clazz);
}
@Override
@SuppressWarnings("unchecked")
protected T readFromSource(Class clazz, HttpHeaders headers, Source source) throws IOException {
try {
if (DOMSource.class.equals(clazz)) {
DOMResult domResult = new DOMResult();
transform(source, domResult);
return (T) new DOMSource(domResult.getNode());
}
else if (SAXSource.class.equals(clazz)) {
ByteArrayInputStream bis = transformToByteArrayInputStream(source);
return (T) new SAXSource(new InputSource(bis));
}
else if (StreamSource.class.equals(clazz) || Source.class.equals(clazz)) {
ByteArrayInputStream bis = transformToByteArrayInputStream(source);
return (T) new StreamSource(bis);
}
else {
throw new HttpMessageConversionException("Could not read class [" + clazz +
"]. Only DOMSource, SAXSource, and StreamSource are supported.");
}
}
catch (TransformerException ex) {
throw new HttpMessageNotReadableException("Could not transform from [" + source + "] to [" + clazz + "]",
ex);
}
}
private ByteArrayInputStream transformToByteArrayInputStream(Source source) throws TransformerException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
transform(source, new StreamResult(bos));
return new ByteArrayInputStream(bos.toByteArray());
}
@Override
protected Long getContentLength(T t, MediaType contentType) {
if (t instanceof DOMSource) {
try {
CountingOutputStream os = new CountingOutputStream();
transform(t, new StreamResult(os));
return os.count;
}
catch (TransformerException ex) {
// ignore
}
}
return null;
}
@Override
protected void writeToResult(T t, HttpHeaders headers, Result result) throws IOException {
try {
transform(t, result);
}
catch (TransformerException ex) {
throw new HttpMessageNotWritableException("Could not transform [" + t + "] to [" + result + "]", ex);
}
}
private static class CountingOutputStream extends OutputStream {
private long count = 0;
@Override
public void write(int b) throws IOException {
count++;
}
@Override
public void write(byte[] b) throws IOException {
count += b.length;
}
@Override
public void write(byte[] b, int off, int len) throws IOException {
count += len;
}
}
}