SPR-5539: Add XML HttpMessageConverters

org.springframework.web/src/main/java/org/springframework/http/converter/xml/AbstractXmlHttpMessageConverter.java

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+/*
+ * Copyright 2008 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.IOException;
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.stream.StreamResult;
+import javax.xml.transform.stream.StreamSource;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.AbstractHttpMessageConverter;
+import org.springframework.http.converter.HttpMessageConversionException;
+
+/**
+ * Abstract base class for {@link org.springframework.http.converter.HttpMessageConverter HttpMessageConverters} that
+ * convert from/to XML.
+ *
+ * <p>By default, subclasses of this converter support {@code text/xml} and {@code application/xml}. This can be
+ * overridden by setting the {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} property.
+ *
+ * @author Arjen Poutsma
+ * @since 3.0
+ */
+public abstract class AbstractXmlHttpMessageConverter<T> extends AbstractHttpMessageConverter<T> {
+
+	private final TransformerFactory transformerFactory = TransformerFactory.newInstance();
+
+	/**
+	 * Protected constructor that sets the {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} to {@code
+	 * text/xml} and {@code application/xml}.
+	 */
+	protected AbstractXmlHttpMessageConverter() {
+		super(new MediaType("application", "xml"), new MediaType("text", "xml"));
+	}
+
+	/** Invokes {@link #readFromSource(Class, HttpHeaders, Source)}. */
+	public final T read(Class<T> clazz, HttpInputMessage inputMessage) throws IOException {
+		return readFromSource(clazz, inputMessage.getHeaders(), new StreamSource(inputMessage.getBody()));
+	}
+
+	/**
+	 * Abstract template method called from {@link #read(Class, HttpInputMessage)}.
+	 *
+	 * @param clazz the type of object to return
+	 * @param headers the HTTP input headers
+	 * @param source the HTTP input body
+	 * @return the converted object
+	 * @throws IOException in case of I/O errors
+	 * @throws org.springframework.http.converter.HttpMessageConversionException in case of conversion errors
+	 */
+	protected abstract T readFromSource(Class<T> clazz, HttpHeaders headers, Source source) throws IOException;
+
+	@Override
+	protected final void writeToInternal(T t, HttpOutputMessage outputMessage) throws IOException {
+		writeToResult(t, outputMessage.getHeaders(), new StreamResult(outputMessage.getBody()));
+	}
+
+	/**
+	 * Abstract template method called from {@link #writeToInternal(Object, HttpOutputMessage)}.
+	 *
+	 * @param t the object to write to the output message
+	 * @param headers the HTTP output headers
+	 * @param result the HTTP output body
+	 * @throws IOException in case of I/O errors
+	 * @throws HttpMessageConversionException in case of conversion errors
+	 */
+	protected abstract void writeToResult(T t, HttpHeaders headers, Result result) throws IOException;
+
+	/**
+	 * Transforms the given {@code Source} to the {@code Result}.
+	 *
+	 * @param source the source to transform from
+	 * @param result the result to transform to
+	 * @throws HttpMessageConversionException in case of transformation errors
+	 */
+	protected void transform(Source source, Result result) {
+		try {
+			Transformer transformer = transformerFactory.newTransformer();
+			transformer.transform(source, result);
+		}
+		catch (TransformerException ex) {
+			throw new HttpMessageConversionException("Could not transform XML", ex);
+		}
+	}
+
+}

org.springframework.web/src/main/java/org/springframework/http/converter/xml/MarshallingHttpMessageConverter.java

@@ -0,0 +1,108 @@
+package org.springframework.http.converter.xml;
+
+import java.io.IOException;
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+
+import org.springframework.beans.factory.InitializingBean;
+import org.springframework.http.HttpHeaders;
+import org.springframework.oxm.Marshaller;
+import org.springframework.oxm.Unmarshaller;
+import org.springframework.util.Assert;
+
+/**
+ * Implementation of {@link org.springframework.http.converter.HttpMessageConverter HttpMessageConverter} that can read
+ * and write XML using Spring's {@link Marshaller} and {@link Unmarshaller} abstractions.
+ *
+ * <p>This converter requires a {@code Marshaller} and {@code Unmarshaller} before it can be used. These can be injected
+ * by the {@linkplain #MarshallingHttpMessageConverter(Marshaller) constructor} or {@linkplain
+ * #setMarshaller(Marshaller) bean properties}.
+ *
+ * <p>By default, this converter supports {@code text/xml} and {@code application/xml}. This can be overridden by
+ * setting the {@link #setSupportedMediaTypes(java.util.List) supportedMediaTypes} property.
+ *
+ * @author Arjen Poutsma
+ * @since 3.0
+ */
+
+public class MarshallingHttpMessageConverter extends AbstractXmlHttpMessageConverter<Object>
+		implements InitializingBean {
+
+	private Marshaller marshaller;
+
+	private Unmarshaller unmarshaller;
+
+	/**
+	 * Construct a new {@code MarshallingHttpMessageConverter} with no {@link Marshaller} or {@link Unmarshaller} set. The
+	 * marshaller and unmarshaller must be set after construction by invoking {@link #setMarshaller(Marshaller)} and {@link
+	 * #setUnmarshaller(Unmarshaller)} .
+	 */
+	public MarshallingHttpMessageConverter() {
+	}
+
+	/**
+	 * Construct a new {@code MarshallingMessageConverter} with the given {@link Marshaller} set. <p>If the given {@link
+	 * Marshaller} also implements the {@link Unmarshaller} interface, it is used for both marshalling and unmarshalling.
+	 * Otherwise, an exception is thrown. <p>Note that all {@code Marshaller} implementations in Spring also implement the
+	 * {@code Unmarshaller} interface, so that you can safely use this constructor.
+	 *
+	 * @param marshaller object used as marshaller and unmarshaller
+	 * @throws IllegalArgumentException when <code>marshaller</code> does not implement the {@link Unmarshaller} interface
+	 * as well
+	 */
+	public MarshallingHttpMessageConverter(Marshaller marshaller) {
+		Assert.notNull(marshaller, "marshaller must not be null");
+		if (!(marshaller instanceof Unmarshaller)) {
+			throw new IllegalArgumentException("Marshaller [" + marshaller + "] does not implement the Unmarshaller " +
+					"interface. Please set an Unmarshaller explicitely by using the " +
+					"MarshallingHttpMessageConverter(Marshaller, Unmarshaller) constructor.");
+		}
+		else {
+			this.marshaller = marshaller;
+			this.unmarshaller = (Unmarshaller) marshaller;
+		}
+	}
+
+	/**
+	 * Construct a new <code>MarshallingMessageConverter</code> with the given {@code Marshaller} and {@code
+	 * Unmarshaller}.
+	 *
+	 * @param marshaller the Marshaller to use
+	 * @param unmarshaller the Unmarshaller to use
+	 */
+	public MarshallingHttpMessageConverter(Marshaller marshaller, Unmarshaller unmarshaller) {
+		Assert.notNull(marshaller, "marshaller must not be null");
+		Assert.notNull(unmarshaller, "unmarshaller must not be null");
+		this.marshaller = marshaller;
+		this.unmarshaller = unmarshaller;
+	}
+
+	/** Set the {@link Marshaller} to be used by this message converter. */
+	public void setMarshaller(Marshaller marshaller) {
+		this.marshaller = marshaller;
+	}
+
+	/** Set the {@link Unmarshaller} to be used by this message converter. */
+	public void setUnmarshaller(Unmarshaller unmarshaller) {
+		this.unmarshaller = unmarshaller;
+	}
+
+	public void afterPropertiesSet() {
+		Assert.notNull(this.marshaller, "Property 'marshaller' is required");
+		Assert.notNull(this.unmarshaller, "Property 'unmarshaller' is required");
+	}
+
+	public boolean supports(Class<?> clazz) {
+		return unmarshaller.supports(clazz);
+	}
+
+	@Override
+	protected Object readFromSource(Class<Object> clazz, HttpHeaders headers, Source source) throws IOException {
+		return unmarshaller.unmarshal(source);
+	}
+
+	@Override
+	protected void writeToResult(Object o, HttpHeaders headers, Result result) throws IOException {
+		marshaller.marshal(o, result);
+	}
+}

org.springframework.web/src/main/java/org/springframework/http/converter/xml/SourceHttpMessageConverter.java

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+package org.springframework.http.converter.xml;
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import javax.xml.transform.Result;
+import javax.xml.transform.Source;
+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.converter.HttpMessageConversionException;
+
+/** @author Arjen Poutsma */
+public class SourceHttpMessageConverter<T extends Source> extends AbstractXmlHttpMessageConverter<T> {
+
+	public boolean supports(Class<? extends T> clazz) {
+		return Source.class.isAssignableFrom(clazz);
+	}
+
+	@Override
+	@SuppressWarnings("unchecked")
+	protected T readFromSource(Class<T> clazz, HttpHeaders headers, Source source) throws IOException {
+		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 = transformToByteArray(source);
+			return (T) new SAXSource(new InputSource(bis));
+		}
+		else if (StreamSource.class.equals(clazz) || Source.class.equals(clazz)) {
+			ByteArrayInputStream bis = transformToByteArray(source);
+			return (T) new StreamSource(bis);
+		}
+		else {
+			throw new HttpMessageConversionException(
+					"Could not read class [" + clazz + "]. Only DOMSource, SAXSource, and StreamSource are supported.");
+		}
+	}
+
+	private ByteArrayInputStream transformToByteArray(Source source) {
+		ByteArrayOutputStream bos = new ByteArrayOutputStream();
+		transform(source, new StreamResult(bos));
+		return new ByteArrayInputStream(bos.toByteArray());
+	}
+
+	@Override
+	protected void writeToResult(T t, HttpHeaders headers, Result result) throws IOException {
+		transform(t, result);
+	}
+}

org.springframework.web/src/main/java/org/springframework/http/converter/xml/package.html

@@ -0,0 +1,7 @@
+<html>
+<body>
+
+Provides a HttpMessageConverter implementations for handling XML.
+
+</body>
+</html>