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/* * Copyright 2002-2019 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 * * https://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.support; import java.io.IOException; import java.io.InputStream; import java.io.OutputStream; import java.io.Reader; import java.io.StringReader; import java.io.Writer; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.parsers.ParserConfigurationException; import javax.xml.stream.XMLEventReader; import javax.xml.stream.XMLEventWriter; import javax.xml.stream.XMLStreamReader; import javax.xml.stream.XMLStreamWriter; 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.SAXResult; import javax.xml.transform.sax.SAXSource; import javax.xml.transform.stax.StAXSource; import javax.xml.transform.stream.StreamResult; import javax.xml.transform.stream.StreamSource; 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.EntityResolver; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.XMLReader; import org.xml.sax.ext.LexicalHandler; import org.springframework.lang.Nullable; import org.springframework.oxm.Marshaller; import org.springframework.oxm.Unmarshaller; import org.springframework.oxm.UnmarshallingFailureException; import org.springframework.oxm.XmlMappingException; import org.springframework.util.Assert; import org.springframework.util.xml.StaxUtils; /** * Abstract implementation of the {@code Marshaller} and {@code Unmarshaller} interface. * This implementation inspects the given {@code Source} or {@code Result}, and * delegates further handling to overridable template methods. * * @author Arjen Poutsma * @author Juergen Hoeller * @since 3.0 */ public abstract class AbstractMarshaller implements Marshaller, Unmarshaller { private static final EntityResolver NO_OP_ENTITY_RESOLVER = (publicId, systemId) -> new InputSource(new StringReader("")); /** Logger available to subclasses. */ protected final Log logger = LogFactory.getLog(getClass()); private boolean supportDtd = false; private boolean processExternalEntities = false; @Nullable private DocumentBuilderFactory documentBuilderFactory; private final Object documentBuilderFactoryMonitor = new Object(); /** * Indicate whether DTD parsing should be supported. * <p>Default is {@code false} meaning that DTD is disabled. */ public void setSupportDtd(boolean supportDtd) { this.supportDtd = supportDtd; } /** * Return whether DTD parsing is supported. */ public boolean isSupportDtd() { return this.supportDtd; } /** * Indicate whether external XML entities are processed when unmarshalling. * <p>Default is {@code false}, meaning that external entities are not resolved. * Note that processing of external entities will only be enabled/disabled when the * {@code Source} passed to {@link #unmarshal(Source)} is a {@link SAXSource} or * {@link StreamSource}. It has no effect for {@link DOMSource} or {@link StAXSource} * instances. * <p><strong>Note:</strong> setting this option to {@code true} also * automatically sets {@link #setSupportDtd} to {@code true}. */ public void setProcessExternalEntities(boolean processExternalEntities) { this.processExternalEntities = processExternalEntities; if (processExternalEntities) { this.supportDtd = true; } } /** * Return whether XML external entities are allowed. * @see #createXmlReader() */ public boolean isProcessExternalEntities() { return this.processExternalEntities; } /** * Build a new {@link Document} from this marshaller's {@link DocumentBuilderFactory}, * as a placeholder for a DOM node. * @see #createDocumentBuilderFactory() * @see #createDocumentBuilder(DocumentBuilderFactory) */ protected Document buildDocument() { try { DocumentBuilder documentBuilder; synchronized (this.documentBuilderFactoryMonitor) { if (this.documentBuilderFactory == null) { this.documentBuilderFactory = createDocumentBuilderFactory(); } documentBuilder = createDocumentBuilder(this.documentBuilderFactory); } return documentBuilder.newDocument(); } catch (ParserConfigurationException ex) { throw new UnmarshallingFailureException("Could not create document placeholder: " + ex.getMessage(), ex); } } /** * 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); factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", !isSupportDtd()); factory.setFeature("http://xml.org/sax/features/external-general-entities", isProcessExternalEntities()); return factory; } /** * Create a {@code DocumentBuilder} that this marshaller will use for creating * DOM documents when passed an empty {@code DOMSource}. * <p>Can be overridden in subclasses, adding further initialization of the builder. * @param factory the {@code DocumentBuilderFactory} that the DocumentBuilder should be created with * @return the {@code DocumentBuilder} * @throws ParserConfigurationException if thrown by JAXP methods */ protected DocumentBuilder createDocumentBuilder(DocumentBuilderFactory factory) throws ParserConfigurationException { DocumentBuilder documentBuilder = factory.newDocumentBuilder(); if (!isProcessExternalEntities()) { documentBuilder.setEntityResolver(NO_OP_ENTITY_RESOLVER); } return documentBuilder; } /** * Create an {@code XMLReader} that this marshaller will when passed an empty {@code SAXSource}. * @return the XMLReader * @throws SAXException if thrown by JAXP methods */ @SuppressWarnings("deprecation") // on JDK 9 protected XMLReader createXmlReader() throws SAXException { XMLReader xmlReader = org.xml.sax.helpers.XMLReaderFactory.createXMLReader(); xmlReader.setFeature("http://apache.org/xml/features/disallow-doctype-decl", !isSupportDtd()); xmlReader.setFeature("http://xml.org/sax/features/external-general-entities", isProcessExternalEntities()); if (!isProcessExternalEntities()) { xmlReader.setEntityResolver(NO_OP_ENTITY_RESOLVER); } return xmlReader; } /** * Determine the default encoding to use for marshalling or unmarshalling from * a byte stream, or {@code null} if none. * <p>The default implementation returns {@code null}. */ @Nullable 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}. * @param graph the root of the object graph to marshal * @param domResult the {@code DOMResult} * @throws XmlMappingException if the given object cannot be marshalled to the result * @throws IllegalArgumentException if the {@code domResult} is empty * @see #marshalDomNode(Object, org.w3c.dom.Node) */ protected void marshalDomResult(Object graph, DOMResult domResult) throws XmlMappingException { if (domResult.getNode() == null) { domResult.setNode(buildDocument()); } marshalDomNode(graph, domResult.getNode()); } /** * Template method for handling {@code StaxResult}s. * <p>This implementation delegates to {@code marshalXMLSteamWriter} or * {@code marshalXMLEventConsumer}, depending on what is contained in the * {@code StaxResult}. * @param graph the root of the object graph to marshal * @param staxResult a JAXP 1.4 {@link StAXSource} * @throws XmlMappingException if the given object cannot be marshalled to the result * @throws IllegalArgumentException if the {@code domResult} is empty * @see #marshalDomNode(Object, org.w3c.dom.Node) */ protected void marshalStaxResult(Object graph, Result staxResult) throws XmlMappingException { XMLStreamWriter streamWriter = StaxUtils.getXMLStreamWriter(staxResult); if (streamWriter != null) { marshalXmlStreamWriter(graph, streamWriter); } else { XMLEventWriter eventWriter = StaxUtils.getXMLEventWriter(staxResult); if (eventWriter != null) { marshalXmlEventWriter(graph, eventWriter); } else { throw new IllegalArgumentException( "StaxResult contains neither XMLStreamWriter nor XMLEventConsumer"); } } } /** * Template method for handling {@code SAXResult}s. * <p>This implementation delegates to {@code marshalSaxHandlers}. * @param graph the root of the object graph to marshal * @param saxResult the {@code SAXResult} * @throws XmlMappingException if the given object cannot be marshalled to the result * @see #marshalSaxHandlers(Object, org.xml.sax.ContentHandler, org.xml.sax.ext.LexicalHandler) */ protected void marshalSaxResult(Object graph, SAXResult saxResult) throws XmlMappingException { ContentHandler contentHandler = saxResult.getHandler(); Assert.notNull(contentHandler, "ContentHandler not set on SAXResult"); LexicalHandler lexicalHandler = saxResult.getLexicalHandler(); marshalSaxHandlers(graph, contentHandler, lexicalHandler); } /** * Template method for handling {@code StreamResult}s. * <p>This implementation delegates to {@code marshalOutputStream} or {@code marshalWriter}, * depending on what is contained in the {@code StreamResult} * @param graph the root of the object graph to marshal * @param streamResult the {@code StreamResult} * @throws IOException if an I/O Exception occurs * @throws XmlMappingException if the given object cannot be marshalled to the result * @throws IllegalArgumentException if {@code streamResult} does neither * contain an {@code OutputStream} nor a {@code Writer} */ protected void marshalStreamResult(Object graph, StreamResult streamResult) throws XmlMappingException, IOException { if (streamResult.getOutputStream() != null) { marshalOutputStream(graph, streamResult.getOutputStream()); } else if (streamResult.getWriter() != null) { marshalWriter(graph, streamResult.getWriter()); } else { throw new IllegalArgumentException("StreamResult contains neither OutputStream nor Writer"); } } // 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 unmarshalStreamSource((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}. * If the given source is empty, an empty source {@code Document} * will be created as a placeholder. * @param domSource the {@code DOMSource} * @return the object graph * @throws XmlMappingException if the given source cannot be mapped to an object * @throws IllegalArgumentException if the {@code domSource} is empty * @see #unmarshalDomNode(org.w3c.dom.Node) */ protected Object unmarshalDomSource(DOMSource domSource) throws XmlMappingException { if (domSource.getNode() == null) { domSource.setNode(buildDocument()); } try { return unmarshalDomNode(domSource.getNode()); } catch (NullPointerException ex) { if (!isSupportDtd()) { throw new UnmarshallingFailureException( "NPE while unmarshalling. " + "This can happen on JDK 1.6 due to the presence of DTD " + "declarations, which are disabled.", ex); } throw ex; } } /** * Template method for handling {@code StaxSource}s. * <p>This implementation delegates to {@code unmarshalXmlStreamReader} or * {@code unmarshalXmlEventReader}. * @param staxSource the {@code StaxSource} * @return the object graph * @throws XmlMappingException if the given source cannot be mapped to an object */ protected Object unmarshalStaxSource(Source staxSource) throws XmlMappingException { XMLStreamReader streamReader = StaxUtils.getXMLStreamReader(staxSource); if (streamReader != null) { return unmarshalXmlStreamReader(streamReader); } else { XMLEventReader eventReader = StaxUtils.getXMLEventReader(staxSource); if (eventReader != null) { return unmarshalXmlEventReader(eventReader); } else { throw new IllegalArgumentException( "StaxSource contains neither XMLStreamReader nor XMLEventReader"); } } } /** * Template method for handling {@code SAXSource}s. * <p>This implementation delegates to {@code unmarshalSaxReader}. * @param saxSource the {@code SAXSource} * @return the object graph * @throws XmlMappingException if the given source cannot be mapped to an object * @throws IOException if an I/O Exception occurs * @see #unmarshalSaxReader(org.xml.sax.XMLReader, org.xml.sax.InputSource) */ protected Object unmarshalSaxSource(SAXSource saxSource) throws XmlMappingException, IOException { if (saxSource.getXMLReader() == null) { try { saxSource.setXMLReader(createXmlReader()); } catch (SAXException ex) { throw new UnmarshallingFailureException("Could not create XMLReader for SAXSource", ex); } } if (saxSource.getInputSource() == null) { saxSource.setInputSource(new InputSource()); } try { return unmarshalSaxReader(saxSource.getXMLReader(), saxSource.getInputSource()); } catch (NullPointerException ex) { if (!isSupportDtd()) { throw new UnmarshallingFailureException( "NPE while unmarshalling. " + "This can happen on JDK 1.6 due to the presence of DTD " + "declarations, which are disabled."); } throw ex; } } /** * Template method for handling {@code StreamSource}s. * <p>This implementation delegates to {@code unmarshalInputStream} or {@code unmarshalReader}. * @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 */ protected Object unmarshalStreamSource(StreamSource streamSource) throws XmlMappingException, IOException { if (streamSource.getInputStream() != null) { if (isProcessExternalEntities() && isSupportDtd()) { return unmarshalInputStream(streamSource.getInputStream()); } else { InputSource inputSource = new InputSource(streamSource.getInputStream()); inputSource.setEncoding(getDefaultEncoding()); return unmarshalSaxSource(new SAXSource(inputSource)); } } else if (streamSource.getReader() != null) { if (isProcessExternalEntities() && isSupportDtd()) { return unmarshalReader(streamSource.getReader()); } else { return unmarshalSaxSource(new SAXSource(new InputSource(streamSource.getReader()))); } } else { return unmarshalSaxSource(new SAXSource(new InputSource(streamSource.getSystemId()))); } } // Abstract template methods /** * Abstract template method for marshalling the given object graph to a DOM {@code Node}. * <p>In practice, node is be a {@code Document} node, a {@code DocumentFragment} node, * or a {@code Element} node. In other words, a node that accepts children. * @param graph the root of the object graph to marshal * @param node the DOM node that will contain the result tree * @throws XmlMappingException if the given object cannot be marshalled to the DOM node * @see org.w3c.dom.Document * @see org.w3c.dom.DocumentFragment * @see org.w3c.dom.Element */ protected abstract void marshalDomNode(Object graph, Node node) throws XmlMappingException; /** * Abstract template method for marshalling the given object to a StAX {@code XMLEventWriter}. * @param graph the root of the object graph to marshal * @param eventWriter the {@code XMLEventWriter} to write to * @throws XmlMappingException if the given object cannot be marshalled to the DOM node */ protected abstract void marshalXmlEventWriter(Object graph, XMLEventWriter eventWriter) throws XmlMappingException; /** * Abstract template method for marshalling the given object to a StAX {@code XMLStreamWriter}. * @param graph the root of the object graph to marshal * @param streamWriter the {@code XMLStreamWriter} to write to * @throws XmlMappingException if the given object cannot be marshalled to the DOM node */ protected abstract void marshalXmlStreamWriter(Object graph, XMLStreamWriter streamWriter) throws XmlMappingException; /** * Abstract template method for marshalling the given object graph to a SAX {@code ContentHandler}. * @param graph the root of the object graph to marshal * @param contentHandler the SAX {@code ContentHandler} * @param lexicalHandler the SAX2 {@code LexicalHandler}. Can be {@code null}. * @throws XmlMappingException if the given object cannot be marshalled to the handlers */ protected abstract void marshalSaxHandlers(Object graph, ContentHandler contentHandler, @Nullable LexicalHandler lexicalHandler) throws XmlMappingException; /** * Abstract template method for marshalling the given object graph to a {@code OutputStream}. * @param graph the root of the object graph to marshal * @param outputStream the {@code OutputStream} to write to * @throws XmlMappingException if the given object cannot be marshalled to the writer * @throws IOException if an I/O exception occurs */ protected abstract void marshalOutputStream(Object graph, OutputStream outputStream) throws XmlMappingException, IOException; /** * Abstract template method for marshalling the given object graph to a {@code Writer}. * @param graph the root of the object graph to marshal * @param writer the {@code Writer} to write to * @throws XmlMappingException if the given object cannot be marshalled to the writer * @throws IOException if an I/O exception occurs */ 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 * @return the object graph * @throws XmlMappingException if the given DOM node cannot be mapped to an object */ protected abstract Object unmarshalDomNode(Node node) throws XmlMappingException; /** * Abstract template method for unmarshalling from a given Stax {@code XMLEventReader}. * @param eventReader the {@code XMLEventReader} to read from * @return the object graph * @throws XmlMappingException if the given event reader cannot be converted to an object */ protected abstract Object unmarshalXmlEventReader(XMLEventReader eventReader) throws XmlMappingException; /** * Abstract template method for unmarshalling from a given Stax {@code XMLStreamReader}. * @param streamReader the {@code XMLStreamReader} to read from * @return the object graph * @throws XmlMappingException if the given stream reader cannot be converted to an object */ protected abstract Object unmarshalXmlStreamReader(XMLStreamReader streamReader) throws XmlMappingException; /** * Abstract template method for unmarshalling using a given SAX {@code XMLReader} * and {@code InputSource}. * @param xmlReader the SAX {@code XMLReader} to parse with * @param inputSource the input source to parse from * @return the object graph * @throws XmlMappingException if the given reader and input source cannot be converted to an object * @throws IOException if an I/O exception occurs */ protected abstract Object unmarshalSaxReader(XMLReader xmlReader, InputSource inputSource) throws XmlMappingException, IOException; /** * Abstract template method for unmarshalling from a given {@code InputStream}. * @param inputStream the {@code InputStreamStream} to read from * @return the object graph * @throws XmlMappingException if the given stream cannot be converted to an object * @throws IOException if an I/O exception occurs */ protected abstract Object unmarshalInputStream(InputStream inputStream) throws XmlMappingException, IOException; /** * Abstract template method for unmarshalling from a given {@code Reader}. * @param reader the {@code Reader} to read from * @return the object graph * @throws XmlMappingException if the given reader cannot be converted to an object * @throws IOException if an I/O exception occurs */ protected abstract Object unmarshalReader(Reader reader) throws XmlMappingException, IOException; }