/*
* 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.oxm.xstream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Reader;
import java.io.Writer;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLEventWriter;
import javax.xml.stream.XMLStreamException;
import javax.xml.stream.XMLStreamReader;
import javax.xml.stream.XMLStreamWriter;
import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.converters.ConversionException;
import com.thoughtworks.xstream.converters.Converter;
import com.thoughtworks.xstream.converters.ConverterMatcher;
import com.thoughtworks.xstream.converters.SingleValueConverter;
import com.thoughtworks.xstream.io.HierarchicalStreamDriver;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.StreamException;
import com.thoughtworks.xstream.io.xml.CompactWriter;
import com.thoughtworks.xstream.io.xml.DomReader;
import com.thoughtworks.xstream.io.xml.DomWriter;
import com.thoughtworks.xstream.io.xml.QNameMap;
import com.thoughtworks.xstream.io.xml.SaxWriter;
import com.thoughtworks.xstream.io.xml.StaxReader;
import com.thoughtworks.xstream.io.xml.StaxWriter;
import com.thoughtworks.xstream.io.xml.XmlFriendlyReplacer;
import com.thoughtworks.xstream.io.xml.XppReader;
import com.thoughtworks.xstream.mapper.CannotResolveClassException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.XMLReader;
import org.xml.sax.ext.LexicalHandler;
import org.springframework.beans.factory.BeanClassLoaderAware;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.oxm.MarshallingFailureException;
import org.springframework.oxm.UncategorizedMappingException;
import org.springframework.oxm.UnmarshallingFailureException;
import org.springframework.oxm.XmlMappingException;
import org.springframework.oxm.support.AbstractMarshaller;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.xml.StaxUtils;
/**
* Implementation of the <code>Marshaller</code> interface for XStream.
*
* <p>By default, XStream does not require any further configuration,
* though class aliases can be used to have more control over the behavior of XStream.
*
* <p>Due to XStream's API, it is required to set the encoding used for writing to OutputStreams.
* It defaults to <code>UTF-8</code>.
*
* <p><b>NOTE:</b> XStream is an XML serialization library, not a data binding library.
* Therefore, it has limited namespace support. As such, it is rather unsuitable for
* usage within Web services.
*
* @author Peter Meijer
* @author Arjen Poutsma
* @since 3.0
* @see #setAliases
* @see #setConverters
* @see #setEncoding
*/
public class XStreamMarshaller extends AbstractMarshaller implements InitializingBean, BeanClassLoaderAware {
/**
* The default encoding used for stream access: UTF-8.
*/
public static final String DEFAULT_ENCODING = "UTF-8";
private final XStream xstream = new XStream();
private HierarchicalStreamDriver streamDriver;
private String encoding = DEFAULT_ENCODING;
private Class[] supportedClasses;
private ClassLoader classLoader;
/**
* Returns the XStream instance used by this marshaller.
*/
public XStream getXStream() {
return this.xstream;
}
/**
* Set the XStream mode.
* @see XStream#XPATH_REFERENCES
* @see XStream#ID_REFERENCES
* @see XStream#NO_REFERENCES
*/
public void setMode(int mode) {
this.getXStream().setMode(mode);
}
/**
* Set the <code>Converters</code> or <code>SingleValueConverters</code> to be registered
* with the <code>XStream</code> instance.
* @see Converter
* @see SingleValueConverter
*/
public void setConverters(ConverterMatcher[] converters) {
for (int i = 0; i < converters.length; i++) {
if (converters[i] instanceof Converter) {
this.getXStream().registerConverter((Converter) converters[i], i);
}
else if (converters[i] instanceof SingleValueConverter) {
this.getXStream().registerConverter((SingleValueConverter) converters[i], i);
}
else {
throw new IllegalArgumentException("Invalid ConverterMatcher [" + converters[i] + "]");
}
}
}
/**
* Sets an alias/type map, consisting of string aliases mapped to classes. Keys are aliases; values are either
* {@code Class} instances, or String class names.
* @see XStream#alias(String, Class)
*/
public void setAliases(Map<String, ?> aliases) throws ClassNotFoundException {
Map<String, Class<?>> classMap = toClassMap(aliases);
for (Map.Entry<String, Class<?>> entry : classMap.entrySet()) {
this.getXStream().alias(entry.getKey(), entry.getValue());
}
}
/**
* Sets the aliases by type map, consisting of string aliases mapped to classes. Any class that is assignable to
* this type will be aliased to the same name. Keys are aliases; values are either
* {@code Class} instances, or String class names.
* @see XStream#aliasType(String, Class)
*/
public void setAliasesByType(Map<String, ?> aliases) throws ClassNotFoundException {
Map<String, Class<?>> classMap = toClassMap(aliases);
for (Map.Entry<String, Class<?>> entry : classMap.entrySet()) {
this.getXStream().aliasType(entry.getKey(), entry.getValue());
}
}
private Map<String, Class<?>> toClassMap(Map<String, ?> map) throws ClassNotFoundException {
Map<String, Class<?>> result = new LinkedHashMap<String, Class<?>>(map.size());
for (Map.Entry<String, ?> entry : map.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
Class type;
if (value instanceof Class) {
type = (Class) value;
}
else if (value instanceof String) {
String s = (String) value;
type = ClassUtils.forName(s, classLoader);
}
else {
throw new IllegalArgumentException("Unknown value [" + value + "], expected String or Class");
}
result.put(key, type);
}
return result;
}
/**
* Sets a field alias/type map, consiting of field names
* @param aliases
* @throws ClassNotFoundException
* @throws NoSuchFieldException
* @see XStream#aliasField(String, Class, String)
*/
public void setFieldAliases(Map<String, String> aliases) throws ClassNotFoundException, NoSuchFieldException {
for (Map.Entry<String, String> entry : aliases.entrySet()) {
String alias = entry.getValue();
String field = entry.getKey();
int idx = field.lastIndexOf('.');
if (idx != -1) {
String className = field.substring(0, idx);
Class clazz = ClassUtils.forName(className, classLoader);
String fieldName = field.substring(idx + 1);
this.getXStream().aliasField(alias, clazz, fieldName);
} else {
throw new IllegalArgumentException("Field name [" + field + "] does not contain '.'");
}
}
}
/**
* Set types to use XML attributes for.
* @see XStream#useAttributeFor(Class)
*/
public void setUseAttributeForTypes(Class[] types) {
for (Class type : types) {
this.getXStream().useAttributeFor(type);
}
}
/**
* Set the types to use XML attributes for. The given map can contain
* either {@code <String, Class>} pairs, in which case
* {@link XStream#useAttributeFor(String, Class)} is called.
* Alternatively, the map can contain {@code <Class, String>}
* or {@code <Class, List<String>>} pairs, which results in
* {@link XStream#useAttributeFor(Class, String)} calls.
*/
public void setUseAttributeFor(Map<?, ?> attributes) {
for (Map.Entry<?, ?> entry : attributes.entrySet()) {
if (entry.getKey() instanceof String) {
if (entry.getValue() instanceof Class) {
this.getXStream().useAttributeFor((String) entry.getKey(), (Class) entry.getValue());
}
else {
throw new IllegalArgumentException(
"Invalid argument 'attributes'. 'useAttributesFor' property takes map of <String, Class>," +
" when using a map key of type String");
}
}
else if (entry.getKey() instanceof Class) {
Class<?> key = (Class<?>) entry.getKey();
if (entry.getValue() instanceof String) {
this.getXStream().useAttributeFor(key, (String) entry.getValue());
}
else if (entry.getValue() instanceof List) {
List list = (List) entry.getValue();
for (Object o : list) {
if (o instanceof String) {
this.getXStream().useAttributeFor(key, (String) o);
}
}
}
else {
throw new IllegalArgumentException("Invalid argument 'attributes'. " +
"'useAttributesFor' property takes either <Class, String> or <Class, List<String>> map," +
" when using a map key of type Class");
}
}
else {
throw new IllegalArgumentException("Invalid argument 'attributes. " +
"'useAttributesFor' property takes either a map key of type String or Class");
}
}
}
/**
* Specify implicit collection fields, as a Map consisting of <code>Class</code> instances
* mapped to comma separated collection field names.
*@see XStream#addImplicitCollection(Class, String)
*/
public void setImplicitCollections(Map<Class<?>, String> implicitCollections) {
for (Map.Entry<Class<?>, String> entry : implicitCollections.entrySet()) {
String[] collectionFields = StringUtils.commaDelimitedListToStringArray(entry.getValue());
for (String collectionField : collectionFields) {
this.getXStream().addImplicitCollection(entry.getKey(), collectionField);
}
}
}
/**
* Specify omitted fields, as a Map consisting of <code>Class</code> instances
* mapped to comma separated field names.
* @see XStream#omitField(Class, String)
*/
public void setOmittedFields(Map<Class<?>, String> omittedFields) {
for (Map.Entry<Class<?>, String> entry : omittedFields.entrySet()) {
String[] fields = StringUtils.commaDelimitedListToStringArray(entry.getValue());
for (String field : fields) {
this.getXStream().omitField(entry.getKey(), field);
}
}
}
/**
* Set the classes for which mappings will be read from class-level JDK 1.5+ annotation metadata.
* @see XStream#processAnnotations(Class)
*/
public void setAnnotatedClass(Class<?> annotatedClass) {
Assert.notNull(annotatedClass, "'annotatedClass' must not be null");
this.getXStream().processAnnotations(annotatedClass);
}
/**
* Set annotated classes for which aliases will be read from class-level JDK 1.5+ annotation metadata.
* @see XStream#processAnnotations(Class[])
*/
public void setAnnotatedClasses(Class<?>[] annotatedClasses) {
Assert.notEmpty(annotatedClasses, "'annotatedClasses' must not be empty");
this.getXStream().processAnnotations(annotatedClasses);
}
/**
* Set the autodetection mode of XStream.
* <p><strong>Note</strong> that auto-detection implies that the XStream is configured while
* it is processing the XML streams, and thus introduces a potential concurrency problem.
* @see XStream#autodetectAnnotations(boolean)
*/
public void setAutodetectAnnotations(boolean autodetectAnnotations) {
this.getXStream().autodetectAnnotations(autodetectAnnotations);
}
/**
* Set the XStream hierarchical stream driver to be used with stream readers and writers.
*/
public void setStreamDriver(HierarchicalStreamDriver streamDriver) {
this.streamDriver = streamDriver;
}
/**
* Set the encoding to be used for stream access.
* @see #DEFAULT_ENCODING
*/
public void setEncoding(String encoding) {
this.encoding = encoding;
}
/**
* Set the classes supported by this marshaller.
* <p>If this property is empty (the default), all classes are supported.
* @see #supports(Class)
*/
public void setSupportedClasses(Class[] supportedClasses) {
this.supportedClasses = supportedClasses;
}
public void setBeanClassLoader(ClassLoader classLoader) {
this.classLoader = classLoader;
}
public final void afterPropertiesSet() throws Exception {
customizeXStream(getXStream());
}
/**
* Template to allow for customizing of the given {@link XStream}.
* <p>The default implementation is empty.
* @param xstream the {@code XStream} instance
*/
protected void customizeXStream(XStream xstream) {
}
public boolean supports(Class clazz) {
if (ObjectUtils.isEmpty(this.supportedClasses)) {
return true;
}
else {
for (Class supportedClass : this.supportedClasses) {
if (supportedClass.isAssignableFrom(clazz)) {
return true;
}
}
return false;
}
}
// Marshalling
@Override
protected void marshalDomNode(Object graph, Node node) throws XmlMappingException {
HierarchicalStreamWriter streamWriter;
if (node instanceof Document) {
streamWriter = new DomWriter((Document) node);
}
else if (node instanceof Element) {
streamWriter = new DomWriter((Element) node, node.getOwnerDocument(), new XmlFriendlyReplacer());
}
else {
throw new IllegalArgumentException("DOMResult contains neither Document nor Element");
}
marshal(graph, streamWriter);
}
@Override
protected void marshalXmlEventWriter(Object graph, XMLEventWriter eventWriter) throws XmlMappingException {
ContentHandler contentHandler = StaxUtils.createContentHandler(eventWriter);
marshalSaxHandlers(graph, contentHandler, null);
}
@Override
protected void marshalXmlStreamWriter(Object graph, XMLStreamWriter streamWriter) throws XmlMappingException {
try {
marshal(graph, new StaxWriter(new QNameMap(), streamWriter));
}
catch (XMLStreamException ex) {
throw convertXStreamException(ex, true);
}
}
@Override
protected void marshalOutputStream(Object graph, OutputStream outputStream) throws XmlMappingException, IOException {
marshalWriter(graph, new OutputStreamWriter(outputStream, this.encoding));
}
@Override
protected void marshalSaxHandlers(Object graph, ContentHandler contentHandler, LexicalHandler lexicalHandler)
throws XmlMappingException {
SaxWriter saxWriter = new SaxWriter();
saxWriter.setContentHandler(contentHandler);
marshal(graph, saxWriter);
}
@Override
protected void marshalWriter(Object graph, Writer writer) throws XmlMappingException, IOException {
if (this.streamDriver != null) {
marshal(graph, this.streamDriver.createWriter(writer));
}
else {
marshal(graph, new CompactWriter(writer));
}
}
/**
* Marshals the given graph to the given XStream HierarchicalStreamWriter.
* Converts exceptions using {@link #convertXStreamException}.
*/
private void marshal(Object graph, HierarchicalStreamWriter streamWriter) {
try {
getXStream().marshal(graph, streamWriter);
}
catch (Exception ex) {
throw convertXStreamException(ex, true);
}
finally {
try {
streamWriter.flush();
}
catch (Exception ex) {
logger.debug("Could not flush HierarchicalStreamWriter", ex);
}
}
}
// Unmarshalling
@Override
protected Object unmarshalDomNode(Node node) throws XmlMappingException {
HierarchicalStreamReader streamReader;
if (node instanceof Document) {
streamReader = new DomReader((Document) node);
}
else if (node instanceof Element) {
streamReader = new DomReader((Element) node);
}
else {
throw new IllegalArgumentException("DOMSource contains neither Document nor Element");
}
return unmarshal(streamReader);
}
@Override
protected Object unmarshalXmlEventReader(XMLEventReader eventReader) throws XmlMappingException {
try {
XMLStreamReader streamReader = StaxUtils.createEventStreamReader(eventReader);
return unmarshalXmlStreamReader(streamReader);
}
catch (XMLStreamException ex) {
throw convertXStreamException(ex, false);
}
}
@Override
protected Object unmarshalXmlStreamReader(XMLStreamReader streamReader) throws XmlMappingException {
return unmarshal(new StaxReader(new QNameMap(), streamReader));
}
@Override
protected Object unmarshalInputStream(InputStream inputStream) throws XmlMappingException, IOException {
return unmarshalReader(new InputStreamReader(inputStream, this.encoding));
}
@Override
protected Object unmarshalReader(Reader reader) throws XmlMappingException, IOException {
if (streamDriver != null) {
return unmarshal(streamDriver.createReader(reader));
}
else {
return unmarshal(new XppReader(reader));
}
}
@Override
protected Object unmarshalSaxReader(XMLReader xmlReader, InputSource inputSource)
throws XmlMappingException, IOException {
throw new UnsupportedOperationException(
"XStreamMarshaller does not support unmarshalling using SAX XMLReaders");
}
private Object unmarshal(HierarchicalStreamReader streamReader) {
try {
return this.getXStream().unmarshal(streamReader);
}
catch (Exception ex) {
throw convertXStreamException(ex, false);
}
}
/**
* Convert the given XStream exception to an appropriate exception from the
* <code>org.springframework.oxm</code> hierarchy.
* <p>A boolean flag is used to indicate whether this exception occurs during marshalling or
* unmarshalling, since XStream itself does not make this distinction in its exception hierarchy.
* @param ex XStream exception that occured
* @param marshalling indicates whether the exception occurs during marshalling (<code>true</code>),
* or unmarshalling (<code>false</code>)
* @return the corresponding <code>XmlMappingException</code>
*/
protected XmlMappingException convertXStreamException(Exception ex, boolean marshalling) {
if (ex instanceof StreamException || ex instanceof CannotResolveClassException ||
ex instanceof ConversionException) {
if (marshalling) {
return new MarshallingFailureException("XStream marshalling exception", ex);
}
else {
return new UnmarshallingFailureException("XStream unmarshalling exception", ex);
}
}
else {
// fallback
return new UncategorizedMappingException("Unknown XStream exception", ex);
}
}
}