mxd2map: src/java/de/intevation/mxd/utils/XMLUtils.java comparison

comparison src/java/de/intevation/mxd/utils/XMLUtils.java @ 27:e5fdc37f8f94

Added XMLUtils to store map information.

author	Raimund Renkert <rrenkert@intevation.de>
date	Fri, 08 Apr 2011 14:21:45 +0200
parents
children	c51376f8e24c

comparison

equal deleted inserted replaced

-:3e24fffdf2bb
+:e5fdc37f8f94
+/*
+* 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.mxd.utils;
+import java.io.ByteArrayInputStream;
+import java.io.FileInputStream;
+import java.io.BufferedInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import javax.xml.namespace.NamespaceContext;
+import javax.xml.namespace.QName;
+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.xml.sax.SAXException;
+/**
+* Some helper functions to ease work with XML concering namespaces, XPATH
+* and so on.
+*  @author <a href="mailto:sascha.teichmann@intevation.de">Sascha L. Teichmann</a>
+*/
+public final class XMLUtils
+{
+/**
+* W3C URL of XForms
+*/
+public static final String XFORM_URL    = "http://www.w3.org/2002/xforms";
+/**
+* W3C prefix of XForms
+*/
+public static final String XFORM_PREFIX = "xform";
+private static Logger logger = Logger.getLogger(XMLUtils.class);
+private XMLUtils() {
+}
+/**
+* Helper class to generate elements and attributes with
+* namespaces.
+*/
+public static class ElementCreator
+{
+/**
+* owner document of the elements to be created
+*/
+protected Document document;
+/**
+* namespace to be used
+*/
+protected String   ns;
+/**
+* prefix to be used
+*/
+protected String   prefix;
+/**
+* Constructor to create an element/attribute creator
+* with a given namespace and namespace prefix using a
+* given owner document.
+* @param document The owning document
+* @param ns       The namespace
+* @param prefix   The namespace prefix
+*/
+public ElementCreator(Document document, String ns, String prefix) {
+this.document = document;
+this.ns       = ns;
+this.prefix   = prefix;
+}
+/**
+* Creates a new element using the owning document with
+* the this creators namespace and namespace prefix.
+* @param name The name of the 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 and its value to a given element.
+* It does not set the namespace prefix.
+* @param element The element to add the attribute to
+* @param name    The name of the attribute
+* @param value   The value of the attribute
+*/
+public void addAttr(Element element, String name, String value) {
+addAttr(element, name, value, false);
+}
+/**
+* Adds a new attribute and its value to a given element.
+* If the namespace prefix is used is decided by the 'addPrefix' flag.
+* @param element The element to add the attribute to
+* @param name    The name of the attribute
+* @param value   The value of the attribute
+* @param addPrefix If true the creators namespace prefix is
+* set on the attribute.
+*/
+public void addAttr(
+Element element,
+String  name,
+String  value,
+boolean addPrefix
+) {
+if (addPrefix) {
+Attr attr = document.createAttributeNS(ns, name);
+attr.setValue(value);
+attr.setPrefix(prefix);
+element.setAttributeNode(attr);
+}
+else {
+element.setAttribute(name, value);
+}
+}
+} // class ElementCreator
+/**
+* Creates a new XML document
+* @return the new XML document ot null if something went wrong during
+* creation.
+*/
+public static final Document newDocument() {
+DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+factory.setNamespaceAware(true);
+try {
+return factory.newDocumentBuilder().newDocument();
+}
+catch (ParserConfigurationException pce) {
+logger.error(pce.getLocalizedMessage(), pce);
+}
+return null;
+}
+/**
+* Loads a XML document namespace aware from a file
+* @param file The file to load.
+* @return the XML document or null if something went wrong
+* during loading.
+*/
+public static final Document parseDocument(File file) {
+InputStream inputStream = null;
+try {
+inputStream = new BufferedInputStream(new FileInputStream(file));
+return parseDocument(inputStream);
+}
+catch (IOException ioe) {
+logger.error(ioe.getLocalizedMessage(), ioe);
+}
+finally {
+if (inputStream != null) {
+try { inputStream.close(); }
+catch (IOException ioe) {}
+}
+}
+return null;
+}
+public static final Document parseDocument(InputStream inputStream) {
+DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+factory.setNamespaceAware(true);
+try {
+return factory.newDocumentBuilder().parse(inputStream);
+}
+catch (ParserConfigurationException pce) {
+logger.error(pce.getLocalizedMessage(), pce);
+}
+catch (SAXException se) {
+logger.error(se.getLocalizedMessage(), se);
+}
+catch (IOException ioe) {
+logger.error(ioe.getLocalizedMessage(), ioe);
+}
+return null;
+}
+/**
+* Creates a new XPath without a namespace context.
+* @return the new XPath.
+*/
+public static final XPath newXPath() {
+return newXPath(null);
+}
+/**
+* Creates a new XPath with a given namespace context.
+* @param namespaceContext The namespace context to be used or null
+* if none should be used.
+* @return The new XPath
+*/
+public static final XPath newXPath(NamespaceContext namespaceContext) {
+XPathFactory factory = XPathFactory.newInstance();
+XPath        xpath   = factory.newXPath();
+if (namespaceContext != null) {
+xpath.setNamespaceContext(namespaceContext);
+}
+return xpath;
+}
+/**
+* Evaluates an XPath query on a given object and returns the result
+* as a given type. No namespace context is used.
+* @param root  The object which is used as the root of the tree to
+* be searched in.
+* @param query The XPath query
+* @param returnTyp The type of the result.
+* @return The result of type 'returnTyp' or null if something
+* went wrong during XPath evaluation.
+*/
+public static final Object xpath(
+Object root,
+String query,
+QName  returnTyp
+) {
+return xpath(root, query, returnTyp, null);
+}
+/**
+* Evaluates an XPath query on a given object and returns the result
+* as a string. A given namespace context is used.
+* @param root  The object which is used as the root of the tree to
+* be searched in.
+* @param query The XPath query
+* @param namespaceContext The namespace context to be used or null
+* if none should be used.
+* @return The result of the query or null if something went wrong
+* during XPath evaluation.
+*/
+public static final String xpathString(
+Object root, String query, NamespaceContext namespaceContext
+) {
+return (String)xpath(
+root, query, XPathConstants.STRING, namespaceContext);
+}
+/**
+* Evaluates an XPath query on a given object and returns the result
+* as a given type. Optionally a namespace context is used.
+* @param root The object which is used as the root of the tree to
+* be searched in.
+* @param query The XPath query
+* @param returnType The type of the result.
+* @param namespaceContext The namespace context to be used or null
+* if none should be used.
+* @return The result of type 'returnTyp' or null if something
+* went wrong during XPath evaluation.
+*/
+public static final Object xpath(
+Object           root,
+String           query,
+QName            returnType,
+NamespaceContext namespaceContext
+) {
+if (root == null) {
+return null;
+}
+try {
+XPath xpath = newXPath(namespaceContext);
+if (xpath != null) {
+return xpath.evaluate(query, root, returnType);
+}
+}
+catch (XPathExpressionException xpee) {
+logger.error(xpee.getLocalizedMessage(), xpee);
+}
+return null;
+}
+/**
+* Streams out an XML document to a given output stream.
+* @param document The document to be streamed out.
+* @param out      The output stream to be used.
+* @return true if operation succeeded else false.
+*/
+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;
+}
+/**
+* Transforms an XML document into a byte array.
+* @param document The document to be streamed out.
+* @return the byte array or null if operation failed or
+* document is null.
+*/
+public static byte [] toByteArray(Document document) {
+if (document == null) {
+return null;
+}
+ByteArrayOutputStream baos = new ByteArrayOutputStream();
+return toStream(document, baos)
+? baos.toByteArray()
+: null;
+}
+public static Document fromByteArray(byte [] data) {
+if (data == null) {
+return null;
+}
+return parseDocument(new ByteArrayInputStream(data));
+}
+}
+// vim:set ts=4 sw=4 si et sta sts=4 fenc=utf8 :

Mercurial > mxd2map

comparison src/java/de/intevation/mxd/utils/XMLUtils.java @ 27:e5fdc37f8f94