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