--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/main/java/de/intevation/artifacts/httpclient/utils/XMLUtils.java	Thu Feb 17 10:31:40 2011 +0000
@@ -0,0 +1,322 @@
+/*
+ * Copyright (c) 2010 by Intevation GmbH
+ *
+ * This program is free software under the LGPL (>=v2.1)
+ * Read the file LGPL.txt coming with the software for details
+ * or visit http://www.gnu.org/licenses/ if it does not exist.
+ */
+
+package de.intevation.artifacts.httpclient.utils;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.StringBufferInputStream;
+import java.io.StringWriter;
+
+import javax.xml.namespace.NamespaceContext;
+import javax.xml.namespace.QName;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerConfigurationException;
+import javax.xml.transform.TransformerException;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.TransformerFactoryConfigurationError;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+import javax.xml.xpath.XPath;
+import javax.xml.xpath.XPathConstants;
+import javax.xml.xpath.XPathExpressionException;
+import javax.xml.xpath.XPathFactory;
+
+import org.apache.log4j.Logger;
+import org.w3c.dom.Attr;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+import org.xml.sax.SAXException;
+
+/**
+ * This class provides many helper-Methods for handling different kinds of 
+ * XML-stuff.
+ * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
+ * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
+ */
+public class XMLUtils {
+
+    /**
+     * the logger, used to log exceptions and additonaly information
+     */
+    private static Logger logger = Logger.getLogger(XMLUtils.class);
+
+    /**
+     * Constructor
+     */
+    public XMLUtils() {
+    }
+
+    /**
+     * Class which could be used to create XML-Elements
+     * @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
+     *
+     */
+    public static class ElementCreator {
+
+        /**
+         * The document the elements should be placed in.
+         */
+        protected Document document;
+
+        /**
+         * The namespace that should be used.
+         */
+        protected String ns;
+
+        /**
+         * The prefix of the namespace that should be used.
+         */
+        protected String prefix;
+
+        /**
+         * Constructor
+         * @param document the document the elements should be placed in
+         * @param ns the namespace that should be used
+         * @param prefix the prefix of the namespace that should be used
+         */
+        public ElementCreator(Document document, String ns, String prefix) {
+            this.document = document;
+            this.ns = ns;
+            this.prefix = prefix;
+        }
+
+        /**
+         * Creates a new element using the given name.
+         * @param name the name of the new element.
+         * @return the new element
+         */
+        public Element create(String name) {
+            Element element = document.createElementNS(ns, name);
+            element.setPrefix(prefix);
+            return element;
+        }
+
+        /**
+         * Adds a new attribute to the given element. 
+         * @param element the element where the attribute should be placed in.
+         * @param name the name of the attribute
+         * @param value the value of the attribute
+         */
+        public void addAttr(Element element, String name, String value) {
+            Attr attr = document.createAttributeNS(ns, name);
+            attr.setValue(value);
+            attr.setPrefix(prefix);
+            element.setAttributeNode(attr);
+        }
+    } // class ElementCreator
+
+    /**
+     * Creates a new document.
+     * @return the new document
+     */
+    public static Document newDocument() {
+        try {
+            return DocumentBuilderFactory.newInstance().newDocumentBuilder()
+                    .newDocument();
+        } catch (ParserConfigurationException pce) {
+            logger.error(pce.getLocalizedMessage(), pce);
+        }
+        return null;
+    }
+
+    /**
+     * Creates a new <code>XPath</code>-expression
+     * @return the new <code>XPath</code>-expression
+     */
+    public static XPath newXPath() {
+        return newXPath(null);
+    }
+
+    /**
+     * Creates a new <code>XPath</code>-expression
+     * @param namespaceContext the namespacecontext that should be used.
+     * @return the new <code>XPath</code>-expression
+     */
+    public static XPath newXPath(NamespaceContext namespaceContext) {
+        XPathFactory factory = XPathFactory.newInstance();
+        XPath xpath = factory.newXPath();
+        if (namespaceContext != null) {
+            xpath.setNamespaceContext(namespaceContext);
+        }
+        return xpath;
+    }
+
+    /**
+     * Fetch the value of an element or attribute from the given resource 
+     * using the query.
+     * @param root the source where the value should be fetch from
+     * @param query the query that should be used to fetch the value
+     * @param namespaceContext the namespacecontext that must match to
+     *                         fetch the value.
+     * @return the value
+     */
+    public static final String xpathString(Object root, String query,
+                                    NamespaceContext namespaceContext) {
+        return (String) xpath(root, query, XPathConstants.STRING,
+                namespaceContext);
+    }
+
+    /**
+     * Fetch the object rom the given resource  using the query.
+     * @param root the source where the value should be fetch from
+     * @param query the query that should be used to fetch the object
+     * @param returnType the Type that must be used to return the object,
+     * @param namespaceContext the namespacecontext that must match to
+     *                         fetch the object.
+     * @return the value
+     */
+    public static final Object xpath(Object root, String query,
+                                     QName returnType,
+                                     NamespaceContext namespaceContext) {
+        if (root == null) {
+            return null;
+        }
+        try {
+            XPath xpath = XMLUtils.newXPath(namespaceContext);
+            if (xpath != null) {
+                return xpath.evaluate(query, root, returnType);
+            }
+        } catch (XPathExpressionException xpee) {
+            logger.error(xpee.getLocalizedMessage(), xpee);
+        }
+        return null;
+    }
+
+    /**
+     * Fetch the object rom the given resource  using the query
+     * and the default <code>ArtifactNamespaceContext</code>
+     * @param root the source where the value should be fetch from
+     * @param query the query that should be used to fetch the object
+     * @param returnType the Type that must be used to return the object
+     * @return the value
+     */
+    public static Object getXPath(Object root, String query, QName returnType) {
+        return getXPath(root,query,returnType,ArtifactNamespaceContext.INSTANCE);
+    }
+
+    /**
+     * Fetch the object rom the given resource  using the query
+     * and the default <code>ArtifactNamespaceContext</code>
+     * @param root the source where the value should be fetch from
+     * @param query the query that should be used to fetch the object
+     * @param returnType the Type that must be used to return the object.
+     * @param context the namespacecontext that must match to
+     *                         fetch the object.
+     * @return the value
+     */
+    public static Object getXPath(
+        Object root, String query, QName returnType, NamespaceContext context
+    ) {
+        return xpath(root, query, returnType, context);
+    }
+
+    /**
+     * Fetch a Nodeset value from a XML-Fragment or XML-Document using the 
+     * given query.
+     * @param root the source where the String should be fetched from
+     * @param query the query that should be used,
+     * @return the Nodeset fetched from the source
+     */
+    public static NodeList getNodeSetXPath(Object root, String query) {
+        return (NodeList) getXPath(root, query, XPathConstants.NODESET);
+    }
+
+    /**
+     * Fetch a Node from a XML-Fragment or XML-Document using the 
+     * given query.
+     * @param root the source where the Node should be fetched from
+     * @param query the query that should be used,
+     * @return the Node fetched from the source
+     */
+    public static Node getNodeXPath(Object root, String query) {
+        return (Node) getXPath(root, query, XPathConstants.NODE);
+    }
+
+    /**
+     * Fetch a String value from a XML-Fragment or XML-Document using the 
+     * given query.
+     * @param root the source where the String should be fetched from
+     * @param xpath the query that should be used,
+     * @return the String fetched from the source
+     */
+    public static String getStringXPath(Object root, String xpath) {
+        return getStringXPath(root, xpath, null);
+    }
+
+    /**
+     * Fetch a String value from a XML-Fragment or XML-Document using the 
+     * given query.
+     * @param root the source where the String should be fetched from
+     * @param query the query that should be used,
+     * @param def the default-value that will be returned id no value was found
+     * @return the String fetched from the source
+     */
+    public static String getStringXPath(Object root, String query, String def) {
+        String s = (String) getXPath(root, query, XPathConstants.STRING);
+        return s == null || s.length() == 0 ? def : s;
+    }
+
+    /**
+     * Reads an XML-document from a given <code>InputStream</code>
+     * @param inputStream the <code>InputStream</code> where the document
+     *                    should be read from
+     * @return the document that could be read.
+     */
+    public static Document readDocument(InputStream inputStream) {
+        Document returnValue = null;
+        try {
+            DocumentBuilderFactory docBuilderFactory = DocumentBuilderFactory
+                    .newInstance();
+            docBuilderFactory.setNamespaceAware(true);
+            DocumentBuilder docBuilder = docBuilderFactory.newDocumentBuilder();
+            returnValue = docBuilder.parse(inputStream);
+        } catch (ParserConfigurationException e) {
+            logger.error(e, e);
+        } catch (SAXException e) {
+            logger.error(e, e);
+        } catch (IOException e) {
+            logger.error(e, e);
+        }
+        return returnValue;
+    }
+
+    /**
+     * Writes a given Document to an <code>OutputStream</code>
+     * @param document the document that should be written
+     * @param out the stream where the document should be written to,
+     * @return true if it was successful, false if not.
+     */
+    public static boolean toStream(Document document, OutputStream out) {
+        try {
+            Transformer transformer =
+                TransformerFactory.newInstance().newTransformer();
+            DOMSource    source = new DOMSource(document);
+            StreamResult result = new StreamResult(out);
+            transformer.transform(source, result);
+            return true;
+        }
+        catch (TransformerConfigurationException tce) {
+            logger.error(tce.getLocalizedMessage(), tce);
+        }
+        catch (TransformerFactoryConfigurationError tfce) {
+            logger.error(tfce.getLocalizedMessage(), tfce);
+        }
+        catch (TransformerException te) {
+            logger.error(te.getLocalizedMessage(), te);
+        }
+        return false;
+    }
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8: