Added StaxEventContentHandler

git-svn-id: https://src.springframework.org/svn/spring-framework/trunk@522 50f2f4bb-b051-0410-bef5-90022cba6387

org.springframework.core/src/main/java/org/springframework/util/xml/StaxEventContentHandler.java

@@ -0,0 +1,189 @@
+/*
+ * Copyright 2002-2009 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.util.xml;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import javax.xml.XMLConstants;
+import javax.xml.namespace.QName;
+import javax.xml.stream.Location;
+import javax.xml.stream.XMLEventFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.Namespace;
+import javax.xml.stream.events.XMLEvent;
+import javax.xml.stream.util.XMLEventConsumer;
+
+import org.xml.sax.Attributes;
+import org.xml.sax.Locator;
+
+import org.springframework.util.StringUtils;
+
+/**
+ * SAX <code>ContentHandler</code> that transforms callback calls to <code>XMLEvent</code>s and writes them to a
+ * <code>XMLEventConsumer</code>.
+ *
+ * @author Arjen Poutsma
+ * @see XMLEvent
+ * @see XMLEventConsumer
+ * @since 3.0
+ */
+class StaxEventContentHandler extends AbstractStaxContentHandler {
+
+	private final XMLEventFactory eventFactory;
+
+	private final XMLEventConsumer eventConsumer;
+
+	private Locator locator;
+
+	/**
+	 * Constructs a new instance of the <code>StaxEventContentHandler</code> that writes to the given
+	 * <code>XMLEventConsumer</code>. A default <code>XMLEventFactory</code> will be created.
+	 *
+	 * @param consumer the consumer to write events to
+	 */
+	StaxEventContentHandler(XMLEventConsumer consumer) {
+		eventFactory = XMLEventFactory.newInstance();
+		eventConsumer = consumer;
+	}
+
+	/**
+	 * Constructs a new instance of the <code>StaxEventContentHandler</code> that uses the given event factory to create
+	 * events and writes to the given <code>XMLEventConsumer</code>.
+	 *
+	 * @param consumer the consumer to write events to
+	 * @param factory  the factory used to create events
+	 */
+	StaxEventContentHandler(XMLEventConsumer consumer, XMLEventFactory factory) {
+		eventFactory = factory;
+		eventConsumer = consumer;
+	}
+
+	public void setDocumentLocator(Locator locator) {
+		this.locator = locator;
+	}
+
+	@Override
+	protected void startDocumentInternal() throws XMLStreamException {
+		consumeEvent(eventFactory.createStartDocument());
+	}
+
+	@Override
+	protected void endDocumentInternal() throws XMLStreamException {
+		consumeEvent(eventFactory.createEndDocument());
+	}
+
+	@Override
+	protected void startElementInternal(QName name, Attributes atts, SimpleNamespaceContext namespaceContext)
+			throws XMLStreamException {
+		List attributes = getAttributes(atts);
+		List namespaces = createNamespaces(namespaceContext);
+		consumeEvent(eventFactory.createStartElement(name, attributes.iterator(), namespaces.iterator()));
+	}
+
+	@Override
+	protected void endElementInternal(QName name, SimpleNamespaceContext namespaceContext) throws XMLStreamException {
+		List namespaces = createNamespaces(namespaceContext);
+		consumeEvent(eventFactory.createEndElement(name, namespaces.iterator()));
+	}
+
+	@Override
+	protected void charactersInternal(char[] ch, int start, int length) throws XMLStreamException {
+		consumeEvent(eventFactory.createCharacters(new String(ch, start, length)));
+	}
+
+	@Override
+	protected void ignorableWhitespaceInternal(char[] ch, int start, int length) throws XMLStreamException {
+		consumeEvent(eventFactory.createIgnorableSpace(new String(ch, start, length)));
+	}
+
+	@Override
+	protected void processingInstructionInternal(String target, String data) throws XMLStreamException {
+		consumeEvent(eventFactory.createProcessingInstruction(target, data));
+	}
+
+	private void consumeEvent(XMLEvent event) throws XMLStreamException {
+		if (locator != null) {
+			eventFactory.setLocation(new SaxLocation(locator));
+		}
+		eventConsumer.add(event);
+	}
+
+	/** Creates and returns a list of <code>NameSpace</code> objects from the <code>NamespaceContext</code>. */
+	private List<Namespace> createNamespaces(SimpleNamespaceContext namespaceContext) {
+		List<Namespace> namespaces = new ArrayList<Namespace>();
+		String defaultNamespaceUri = namespaceContext.getNamespaceURI(XMLConstants.DEFAULT_NS_PREFIX);
+		if (StringUtils.hasLength(defaultNamespaceUri)) {
+			namespaces.add(eventFactory.createNamespace(defaultNamespaceUri));
+		}
+		for (Iterator iterator = namespaceContext.getBoundPrefixes(); iterator.hasNext();) {
+			String prefix = (String) iterator.next();
+			String namespaceUri = namespaceContext.getNamespaceURI(prefix);
+			namespaces.add(eventFactory.createNamespace(prefix, namespaceUri));
+		}
+		return namespaces;
+	}
+
+	private List<Attribute> getAttributes(Attributes attributes) {
+		List<Attribute> list = new ArrayList<Attribute>();
+		for (int i = 0; i < attributes.getLength(); i++) {
+			QName name = toQName(attributes.getURI(i), attributes.getQName(i));
+			if (!("xmlns".equals(name.getLocalPart()) || "xmlns".equals(name.getPrefix()))) {
+				list.add(eventFactory.createAttribute(name, attributes.getValue(i)));
+			}
+		}
+		return list;
+	}
+
+	//
+	// No operation
+	//
+
+	@Override
+	protected void skippedEntityInternal(String name) throws XMLStreamException {
+	}
+
+	private static class SaxLocation implements Location {
+
+		private Locator locator;
+
+		private SaxLocation(Locator locator) {
+			this.locator = locator;
+		}
+
+		public int getLineNumber() {
+			return locator.getLineNumber();
+		}
+
+		public int getColumnNumber() {
+			return locator.getColumnNumber();
+		}
+
+		public int getCharacterOffset() {
+			return -1;
+		}
+
+		public String getPublicId() {
+			return locator.getPublicId();
+		}
+
+		public String getSystemId() {
+			return locator.getSystemId();
+		}
+	}
+}

org.springframework.core/src/test/java/org/springframework/util/xml/StaxEventContentHandlerTests.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2002-2009 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.util.xml;
+
+import java.io.Writer;
+import javax.xml.stream.XMLOutputFactory;
+import javax.xml.stream.XMLStreamException;
+
+public class StaxEventContentHandlerTests extends AbstractStaxContentHandlerTestCase {
+
+	@Override
+	protected AbstractStaxContentHandler createStaxContentHandler(Writer writer) throws XMLStreamException {
+		XMLOutputFactory outputFactory = XMLOutputFactory.newInstance();
+		return new StaxEventContentHandler(outputFactory.createXMLEventWriter(writer));
+	}
+}