AbstractMarshaller pre-implements getDefaultEncoding() method

Issue: SPR-11635

Author: jhoeller

spring-oxm/src/main/java/org/springframework/oxm/support/AbstractMarshaller.java

@@ -40,6 +40,7 @@
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
+import org.w3c.dom.Document;
 import org.w3c.dom.Node;
 import org.xml.sax.ContentHandler;
 import org.xml.sax.InputSource;
@@ -66,15 +67,15 @@
  */
 public abstract class AbstractMarshaller implements Marshaller, Unmarshaller {
 
-	/** Logger available to subclasses. */
+	/** Logger available to subclasses */
 	protected final Log logger = LogFactory.getLog(getClass());
 
+	private boolean processExternalEntities = false;
+
 	private DocumentBuilderFactory documentBuilderFactory;
 
 	private final Object documentBuilderFactoryMonitor = new Object();
 
-	private boolean processExternalEntities = false;
-
 
 	/**
 	 * Indicates whether external XML entities are processed when unmarshalling.
@@ -89,83 +90,48 @@ public void setProcessExternalEntities(boolean processExternalEntities) {
 	}
 
 	/**
-	 * @return the configured value for whether XML external entities are allowed.
+	 * Returns the configured value for whether XML external entities are allowed.
+	 * @see #createXmlReader()
 	 */
 	public boolean isProcessExternalEntities() {
 		return this.processExternalEntities;
 	}
 
-	/**
-	 * @return the default encoding to use for marshalling or unmarshalling from
-	 * 	a byte stream, or {@code null}.
-	 */
-	abstract protected String getDefaultEncoding();
-
 
 	/**
-	 * Marshals the object graph with the given root into the provided {@code javax.xml.transform.Result}.
-	 * <p>This implementation inspects the given result, and calls {@code marshalDomResult},
-	 * {@code marshalSaxResult}, or {@code marshalStreamResult}.
-	 * @param graph the root of the object graph to marshal
-	 * @param result the result to marshal to
-	 * @throws IOException if an I/O exception occurs
-	 * @throws XmlMappingException if the given object cannot be marshalled to the result
-	 * @throws IllegalArgumentException if {@code result} if neither a {@code DOMResult},
-	 * a {@code SAXResult}, nor a {@code StreamResult}
-	 * @see #marshalDomResult(Object, javax.xml.transform.dom.DOMResult)
-	 * @see #marshalSaxResult(Object, javax.xml.transform.sax.SAXResult)
-	 * @see #marshalStreamResult(Object, javax.xml.transform.stream.StreamResult)
+	 * Build a new {@link Document} from this marshaller's {@link DocumentBuilderFactory}.
+	 * @see #createDocumentBuilderFactory()
+	 * @see #createDocumentBuilder(DocumentBuilderFactory)
 	 */
-	@Override
-	public final void marshal(Object graph, Result result) throws IOException, XmlMappingException {
-		if (result instanceof DOMResult) {
-			marshalDomResult(graph, (DOMResult) result);
-		}
-		else if (StaxUtils.isStaxResult(result)) {
-			marshalStaxResult(graph, result);
-		}
-		else if (result instanceof SAXResult) {
-			marshalSaxResult(graph, (SAXResult) result);
-		}
-		else if (result instanceof StreamResult) {
-			marshalStreamResult(graph, (StreamResult) result);
+	protected Document buildDocument() {
+		try {
+			synchronized (this.documentBuilderFactoryMonitor) {
+				if (this.documentBuilderFactory == null) {
+					this.documentBuilderFactory = createDocumentBuilderFactory();
+				}
+			}
+			DocumentBuilder documentBuilder = createDocumentBuilder(this.documentBuilderFactory);
+			return documentBuilder.newDocument();
 		}
-		else {
-			throw new IllegalArgumentException("Unknown Result type: " + result.getClass());
+		catch (ParserConfigurationException ex) {
+			throw new UnmarshallingFailureException(
+					"Could not create document placeholder for DOMSource: " + ex.getMessage(), ex);
 		}
 	}
 
 	/**
-	 * Unmarshals the given provided {@code javax.xml.transform.Source} into an object graph.
-	 * <p>This implementation inspects the given result, and calls {@code unmarshalDomSource},
-	 * {@code unmarshalSaxSource}, or {@code unmarshalStreamSource}.
-	 * @param source the source to marshal from
-	 * @return the object graph
-	 * @throws IOException if an I/O Exception occurs
-	 * @throws XmlMappingException if the given source cannot be mapped to an object
-	 * @throws IllegalArgumentException if {@code source} is neither a {@code DOMSource},
-	 * a {@code SAXSource}, nor a {@code StreamSource}
-	 * @see #unmarshalDomSource(javax.xml.transform.dom.DOMSource)
-	 * @see #unmarshalSaxSource(javax.xml.transform.sax.SAXSource)
-	 * @see #unmarshalStreamSource(javax.xml.transform.stream.StreamSource)
+	 * Create a {@code DocumentBuilder} that this marshaller will use for creating
+	 * DOM documents when passed an empty {@code DOMSource}.
+	 * <p>The resulting {@code DocumentBuilderFactory} is cached, so this method
+	 * will only be called once.
+	 * @return the DocumentBuilderFactory
+	 * @throws ParserConfigurationException if thrown by JAXP methods
 	 */
-	@Override
-	public final Object unmarshal(Source source) throws IOException, XmlMappingException {
-		if (source instanceof DOMSource) {
-			return unmarshalDomSource((DOMSource) source);
-		}
-		else if (StaxUtils.isStaxSource(source)) {
-			return unmarshalStaxSource(source);
-		}
-		else if (source instanceof SAXSource) {
-			return unmarshalSaxSource((SAXSource) source);
-		}
-		else if (source instanceof StreamSource) {
-			return unmarshalStreamSourceNoExternalEntitities((StreamSource) source);
-		}
-		else {
-			throw new IllegalArgumentException("Unknown Source type: " + source.getClass());
-		}
+	protected DocumentBuilderFactory createDocumentBuilderFactory() throws ParserConfigurationException {
+		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+		factory.setValidating(false);
+		factory.setNamespaceAware(true);
+		return factory;
 	}
 
 	/**
@@ -182,21 +148,6 @@ protected DocumentBuilder createDocumentBuilder(DocumentBuilderFactory factory)
 		return factory.newDocumentBuilder();
 	}
 
-	/**
-	 * Create a {@code DocumentBuilder} that this marshaller will use for creating
-	 * DOM documents when passed an empty {@code DOMSource}.
-	 * <p>The resulting {@code DocumentBuilderFactory} is cached, so this method
-	 * will only be called once.
-	 * @return the DocumentBuilderFactory
-	 * @throws ParserConfigurationException if thrown by JAXP methods
-	 */
-	protected DocumentBuilderFactory createDocumentBuilderFactory() throws ParserConfigurationException {
-		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
-		factory.setValidating(false);
-		factory.setNamespaceAware(true);
-		return factory;
-	}
-
 	/**
 	 * Create an {@code XMLReader} that this marshaller will when passed an empty {@code SAXSource}.
 	 * @return the XMLReader
@@ -208,9 +159,50 @@ protected XMLReader createXmlReader() throws SAXException {
 		return xmlReader;
 	}
 
+	/**
+	 * Determine the default encoding to use for marshalling or unmarshalling from
+	 * a byte stream, or {@code null} if none.
+	 */
+	protected String getDefaultEncoding() {
+		return null;
+	}
+
 
 	// Marshalling
 
+	/**
+	 * Marshals the object graph with the given root into the provided {@code javax.xml.transform.Result}.
+	 * <p>This implementation inspects the given result, and calls {@code marshalDomResult},
+	 * {@code marshalSaxResult}, or {@code marshalStreamResult}.
+	 * @param graph the root of the object graph to marshal
+	 * @param result the result to marshal to
+	 * @throws IOException if an I/O exception occurs
+	 * @throws XmlMappingException if the given object cannot be marshalled to the result
+	 * @throws IllegalArgumentException if {@code result} if neither a {@code DOMResult},
+	 * a {@code SAXResult}, nor a {@code StreamResult}
+	 * @see #marshalDomResult(Object, javax.xml.transform.dom.DOMResult)
+	 * @see #marshalSaxResult(Object, javax.xml.transform.sax.SAXResult)
+	 * @see #marshalStreamResult(Object, javax.xml.transform.stream.StreamResult)
+	 */
+	@Override
+	public final void marshal(Object graph, Result result) throws IOException, XmlMappingException {
+		if (result instanceof DOMResult) {
+			marshalDomResult(graph, (DOMResult) result);
+		}
+		else if (StaxUtils.isStaxResult(result)) {
+			marshalStaxResult(graph, result);
+		}
+		else if (result instanceof SAXResult) {
+			marshalSaxResult(graph, (SAXResult) result);
+		}
+		else if (result instanceof StreamResult) {
+			marshalStreamResult(graph, (StreamResult) result);
+		}
+		else {
+			throw new IllegalArgumentException("Unknown Result type: " + result.getClass());
+		}
+	}
+
 	/**
 	 * Template method for handling {@code DOMResult}s.
 	 * <p>This implementation delegates to {@code marshalDomNode}.
@@ -222,19 +214,7 @@ protected XMLReader createXmlReader() throws SAXException {
 	 */
 	protected void marshalDomResult(Object graph, DOMResult domResult) throws XmlMappingException {
 		if (domResult.getNode() == null) {
-			try {
-				synchronized (this.documentBuilderFactoryMonitor) {
-					if (this.documentBuilderFactory == null) {
-						this.documentBuilderFactory = createDocumentBuilderFactory();
-					}
-				}
-				DocumentBuilder documentBuilder = createDocumentBuilder(this.documentBuilderFactory);
-				domResult.setNode(documentBuilder.newDocument());
-			}
-			catch (ParserConfigurationException ex) {
-				throw new UnmarshallingFailureException(
-						"Could not create document placeholder for DOMResult: " + ex.getMessage(), ex);
-			}
+			domResult.setNode(buildDocument());
 		}
 		marshalDomNode(graph, domResult.getNode());
 	}
@@ -309,6 +289,39 @@ else if (streamResult.getWriter() != null) {
 
 	// Unmarshalling
 
+	/**
+	 * Unmarshals the given provided {@code javax.xml.transform.Source} into an object graph.
+	 * <p>This implementation inspects the given result, and calls {@code unmarshalDomSource},
+	 * {@code unmarshalSaxSource}, or {@code unmarshalStreamSource}.
+	 * @param source the source to marshal from
+	 * @return the object graph
+	 * @throws IOException if an I/O Exception occurs
+	 * @throws XmlMappingException if the given source cannot be mapped to an object
+	 * @throws IllegalArgumentException if {@code source} is neither a {@code DOMSource},
+	 * a {@code SAXSource}, nor a {@code StreamSource}
+	 * @see #unmarshalDomSource(javax.xml.transform.dom.DOMSource)
+	 * @see #unmarshalSaxSource(javax.xml.transform.sax.SAXSource)
+	 * @see #unmarshalStreamSource(javax.xml.transform.stream.StreamSource)
+	 */
+	@Override
+	public final Object unmarshal(Source source) throws IOException, XmlMappingException {
+		if (source instanceof DOMSource) {
+			return unmarshalDomSource((DOMSource) source);
+		}
+		else if (StaxUtils.isStaxSource(source)) {
+			return unmarshalStaxSource(source);
+		}
+		else if (source instanceof SAXSource) {
+			return unmarshalSaxSource((SAXSource) source);
+		}
+		else if (source instanceof StreamSource) {
+			return unmarshalStreamSourceNoExternalEntitities((StreamSource) source);
+		}
+		else {
+			throw new IllegalArgumentException("Unknown Source type: " + source.getClass());
+		}
+	}
+
 	/**
 	 * Template method for handling {@code DOMSource}s.
 	 * <p>This implementation delegates to {@code unmarshalDomNode}.
@@ -322,19 +335,7 @@ else if (streamResult.getWriter() != null) {
 	 */
 	protected Object unmarshalDomSource(DOMSource domSource) throws XmlMappingException {
 		if (domSource.getNode() == null) {
-			try {
-				synchronized (this.documentBuilderFactoryMonitor) {
-					if (this.documentBuilderFactory == null) {
-						this.documentBuilderFactory = createDocumentBuilderFactory();
-					}
-				}
-				DocumentBuilder documentBuilder = createDocumentBuilder(this.documentBuilderFactory);
-				domSource.setNode(documentBuilder.newDocument());
-			}
-			catch (ParserConfigurationException ex) {
-				throw new UnmarshallingFailureException(
-						"Could not create document placeholder for DOMSource: " + ex.getMessage(), ex);
-			}
+			domSource.setNode(buildDocument());
 		}
 		return unmarshalDomNode(domSource.getNode());
 	}
@@ -391,18 +392,17 @@ protected Object unmarshalSaxSource(SAXSource saxSource) throws XmlMappingExcept
 	 * Template method for handling {@code StreamSource}s with protection against
 	 * the XML External Entity (XXE) processing vulnerability taking into account
 	 * the value of the {@link #setProcessExternalEntities(boolean)} property.
-	 * <p>
-	 * The default implementation wraps the StreamSource as a SAXSource and delegates
+	 * <p>The default implementation wraps the StreamSource as a SAXSource and delegates
 	 * to {@link #unmarshalSaxSource(javax.xml.transform.sax.SAXSource)}.
-	 *
 	 * @param streamSource the {@code StreamSource}
 	 * @return the object graph
 	 * @throws IOException if an I/O exception occurs
 	 * @throws XmlMappingException if the given source cannot be mapped to an object
-	 *
 	 * @see <a href="https://www.owasp.org/index.php/XML_External_Entity_(XXE)_Processing">XML_External_Entity_(XXE)_Processing</a>
 	 */
-	protected Object unmarshalStreamSourceNoExternalEntitities(StreamSource streamSource) throws XmlMappingException, IOException {
+	protected Object unmarshalStreamSourceNoExternalEntitities(StreamSource streamSource)
+			throws XmlMappingException, IOException {
+
 		InputSource inputSource;
 		if (streamSource.getInputStream() != null) {
 			inputSource = new InputSource(streamSource.getInputStream());
@@ -420,10 +420,9 @@ else if (streamSource.getReader() != null) {
 	/**
 	 * Template method for handling {@code StreamSource}s.
 	 * <p>This implementation defers to {@code unmarshalInputStream} or {@code unmarshalReader}.
-	 * <p>As of 3.2.8 and 4.0.2 this method is no longer invoked from
+	 * <p>As of Spring 3.2.8, this method is no longer invoked from
 	 * {@link #unmarshal(javax.xml.transform.Source)}. The method invoked instead is
 	 * {@link #unmarshalStreamSourceNoExternalEntitities(javax.xml.transform.stream.StreamSource)}.
-	 *
 	 * @param streamSource the {@code StreamSource}
 	 * @return the object graph
 	 * @throws IOException if an I/O exception occurs
@@ -507,7 +506,6 @@ protected abstract void marshalOutputStream(Object graph, OutputStream outputStr
 	protected abstract void marshalWriter(Object graph, Writer writer)
 			throws XmlMappingException, IOException;
 
-
 	/**
 	 * Abstract template method for unmarshalling from a given DOM {@code Node}.
 	 * @param node the DOM node that contains the objects to be unmarshalled