OPEN - issue INT-388: XPath message splitter

First pass implementation no namespace support

org.springframework.integration.xml/src/main/java/org/springframework/integration/xml/splitter/XPathMessageSplitter.java

@@ -0,0 +1,160 @@
+/*
+ * Copyright 2002-2007 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.integration.xml.splitter;
+
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.TransformerFactoryConfigurationError;
+import javax.xml.transform.dom.DOMSource;
+
+import org.springframework.integration.message.Message;
+import org.springframework.integration.message.MessagingException;
+import org.springframework.integration.splitter.AbstractSplitter;
+import org.springframework.integration.xml.DefaultXmlPayloadConverter;
+import org.springframework.integration.xml.XmlPayloadConverter;
+import org.springframework.util.Assert;
+import org.springframework.xml.transform.StringResult;
+import org.springframework.xml.xpath.XPathExpression;
+import org.springframework.xml.xpath.XPathExpressionFactory;
+import org.w3c.dom.Document;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+
+/**
+ * Use {@link XPathExpression} to split a {@link Document} or {@link String}
+ * payload into a {@link NodeList} each {@link Node} is then
+ * @author Jonas Partner
+ * 
+ */
+public class XPathMessageSplitter extends AbstractSplitter {
+
+	private final XPathExpression xpathExpression;
+
+	private volatile boolean createDocuments;
+
+	private volatile DocumentBuilderFactory documentBuilderFactory;
+
+	private volatile XmlPayloadConverter xmlPayloadConverter = new DefaultXmlPayloadConverter();
+
+	public XPathMessageSplitter(String expression) {
+		this(expression, new HashMap<String, String>());
+	}
+
+	public XPathMessageSplitter(String expression, Map<String, String> namespaces) {
+		this(XPathExpressionFactory.createXPathExpression(expression, namespaces));
+	}
+
+	public XPathMessageSplitter(XPathExpression xpathExpression) {
+		this.xpathExpression = xpathExpression;
+		this.documentBuilderFactory = DocumentBuilderFactory.newInstance();
+		this.documentBuilderFactory.setNamespaceAware(true);
+	}
+
+	@Override
+	protected Object splitMessage(Message<?> message) {
+		try {
+			Object payload = message.getPayload();
+			Object toReturn = null;
+
+			if (payload instanceof Node) {
+				toReturn = splitNodePayload((Node) payload, message);
+			}
+			else if (payload instanceof String) {
+				payload = xmlPayloadConverter.convertToDocument(payload);
+				toReturn = splitStringPayload(message);
+			}
+			return toReturn;
+		}
+		catch (ParserConfigurationException e) {
+			throw new MessagingException(message, "Error creating DocumentBuilder", e);
+		}
+		catch (Exception e) {
+			throw new MessagingException(message, "Error transforming payload", e);
+		}
+
+	}
+
+	private Object splitStringPayload(Message<?> message) throws ParserConfigurationException,
+			TransformerFactoryConfigurationError, TransformerException {
+		Node node = xmlPayloadConverter.convertToDocument(message.getPayload());
+		List<Node> nodes = splitNodePayload(node, message);
+		Transformer transformer = TransformerFactory.newInstance().newTransformer();
+		List<String> splitStrings = new ArrayList<String>(nodes.size());
+		for (Node nodeFromList : nodes) {
+			StringResult result = new StringResult();
+			transformer.transform(new DOMSource(nodeFromList), result);
+			splitStrings.add(result.toString());
+		}
+		return splitStrings;
+	}
+
+	@SuppressWarnings("unchecked")
+	protected List<Node> splitNodePayload(Node node, Message message) throws ParserConfigurationException {
+		List<Node> nodeList = xpathExpression.evaluateAsNodeList(node);
+		if (nodeList.size() == 0) {
+			throw new MessagingException(message, "Could not split message with XPath " + xpathExpression);
+		}
+		if (createDocuments) {
+			return convertNodesToDocuments(nodeList);
+		}
+		return nodeList;
+
+	}
+
+	private List<Node> convertNodesToDocuments(List<Node> nodeList) throws ParserConfigurationException {
+		DocumentBuilder documentBuilder;
+		documentBuilder = getNewDocumentBuilder();
+
+		List<Node> docList = new ArrayList<Node>(nodeList.size());
+		for (Node node : nodeList) {
+			Document doc = documentBuilder.newDocument();
+			doc.importNode(node, true);
+			docList.add(doc);
+		}
+		return docList;
+	}
+
+	public void setCreateDocuments(boolean createDocuments) {
+		this.createDocuments = createDocuments;
+	}
+
+	public void setDocumentBuilder(DocumentBuilderFactory documentBuilderFactory) {
+		Assert.notNull(documentBuilderFactory, "Document builder can not be null");
+		this.documentBuilderFactory = documentBuilderFactory;
+	}
+
+	public void setXmlPayloadConverter(XmlPayloadConverter xmlPayloadConverter) {
+		Assert.notNull(xmlPayloadConverter, "Xml Payload converter can not be null");
+		this.xmlPayloadConverter = xmlPayloadConverter;
+
+	}
+
+	protected DocumentBuilder getNewDocumentBuilder() throws ParserConfigurationException {
+		synchronized (documentBuilderFactory) {
+			return documentBuilderFactory.newDocumentBuilder();
+		}
+	}
+
+}