[New] Added XmlHelper

src/main/java/ch/eitchnet/utils/exceptions/XmlException.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2012, Robert von Burg
+ *
+ * All rights reserved.
+ *
+ * This file is part of the XXX.
+ *
+ *  XXX is free software: you can redistribute 
+ *  it and/or modify it under the terms of the GNU General Public License as 
+ *  published by the Free Software Foundation, either version 3 of the License, 
+ *  or (at your option) any later version.
+ *
+ *  XXX is distributed in the hope that it will 
+ *  be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with XXX.  If not, see 
+ *  <http://www.gnu.org/licenses/>.
+ */
+package ch.eitchnet.utils.exceptions;
+
+/**
+ * @author Robert von Burg <eitch@eitchnet.ch>
+ * 
+ */
+public class XmlException extends RuntimeException {
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * @param message
+	 */
+	public XmlException(String message) {
+		super(message);
+	}
+
+	/**
+	 * @param message
+	 * @param cause
+	 */
+	public XmlException(String message, Throwable cause) {
+		super(message, cause);
+	}
+}

src/main/java/ch/eitchnet/utils/helper/XmlHelper.java

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+/*
+ * Copyright (c) 2010 - 2012
+ * 
+ * This file is part of ch.eitchnet.java.utils.
+ *
+ * ch.eitchnet.java.utils is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * ch.eitchnet.java.utils is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with ch.eitchnet.java.utils.  If not, see <http://www.gnu.org/licenses/>.
+ * 
+ */
+package ch.eitchnet.utils.helper;
+
+import java.io.File;
+import java.io.IOException;
+
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+import javax.xml.parsers.SAXParser;
+import javax.xml.parsers.SAXParserFactory;
+import javax.xml.transform.OutputKeys;
+import javax.xml.transform.Source;
+import javax.xml.transform.Transformer;
+import javax.xml.transform.TransformerFactory;
+import javax.xml.transform.dom.DOMSource;
+import javax.xml.transform.stream.StreamResult;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.w3c.dom.DOMException;
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.xml.sax.SAXException;
+import org.xml.sax.helpers.DefaultHandler;
+
+import ch.eitchnet.utils.exceptions.XmlException;
+
+/**
+ * Helper class for performing XML based tasks using Dom4J
+ * 
+ * @author Robert von Burg <eitch@eitchnet.ch>
+ */
+public class XmlHelper {
+
+	/**
+	 * DEFAULT_ENCODING = "UTF-8" : defines the default UTF-8 encoding expected of XML files
+	 */
+	public static final String DEFAULT_ENCODING = "UTF-8";
+
+	private static final Logger logger = LoggerFactory.getLogger(XmlHelper.class);
+
+	/**
+	 * Parses an XML file on the file system using dom4j and returns the resulting {@link Document} object
+	 * 
+	 * @param xmlFile
+	 *            the {@link File} which has the path to the XML file to read
+	 * 
+	 * @return a {@link Document} object containing the dom4j {@link Element}s of the XML file
+	 */
+	public static void parseDocument(File xmlFile, DefaultHandler xmlHandler) {
+
+		try {
+
+			SAXParserFactory spf = SAXParserFactory.newInstance();
+
+			SAXParser sp = spf.newSAXParser();
+			XmlHelper.logger.info("Parsing XML document " + xmlFile.getAbsolutePath());
+			sp.parse(xmlFile, xmlHandler);
+
+		} catch (ParserConfigurationException e) {
+			throw new XmlException("Failed to initialize a SAX Parser: " + e.getLocalizedMessage(), e);
+		} catch (SAXException e) {
+			throw new XmlException("The XML file " + xmlFile.getAbsolutePath() + " is not parseable:", e);
+		} catch (IOException e) {
+			throw new XmlException("The XML could not be read: " + xmlFile.getAbsolutePath());
+		}
+	}
+
+	/**
+	 * Writes a dom4j {@link Document} to an XML file on the file system
+	 * 
+	 * @param document
+	 *            the {@link Document} to write to the file system
+	 * @param file
+	 *            the {@link File} describing the path on the file system where the XML file should be written to
+	 * 
+	 * @throws RuntimeException
+	 *             if something went wrong while creating the XML configuration, or writing the element
+	 */
+	public static void writeDocument(Document document, File file) throws RuntimeException {
+
+		XmlHelper.logger.info("Exporting document element " + document.getNodeName() + " to " + file.getAbsolutePath());
+
+		try {
+
+			String encoding = document.getInputEncoding();
+			if (encoding == null || encoding.isEmpty()) {
+				encoding = XmlHelper.DEFAULT_ENCODING;
+			}
+
+			// Set up a transformer
+			TransformerFactory transfac = TransformerFactory.newInstance();
+			Transformer transformer = transfac.newTransformer();
+			transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "no");
+			transformer.setOutputProperty(OutputKeys.INDENT, "yes");
+			transformer.setOutputProperty(OutputKeys.METHOD, "xml");
+			transformer.setOutputProperty(OutputKeys.ENCODING, encoding);
+			transformer.setOutputProperty("{http://xml.apache.org/xalan}indent-amount", "2");
+			//transformer.setOutputProperty("{http://xml.apache.org/xalan}line-separator", "\t");
+
+			// Transform to file
+			StreamResult result = new StreamResult(file);
+			Source xmlSource = new DOMSource(document);
+			transformer.transform(xmlSource, result);
+
+		} catch (Exception e) {
+
+			throw new XmlException("Exception while exporting to file: " + e, e);
+
+		}
+	}
+
+	/**
+	 * Writes a dom4j {@link Element} to an XML file on the file system
+	 * 
+	 * @param rootElement
+	 *            the {@link Element} to write to the file system
+	 * @param file
+	 *            the {@link File} describing the path on the file system where the XML file should be written to
+	 * @param encoding
+	 *            encoding to use to write the file
+	 * 
+	 * @throws RuntimeException
+	 *             if something went wrong while creating the XML configuration, or writing the element
+	 */
+	public static void writeElement(Element rootElement, File file, String encoding) throws RuntimeException {
+
+		Document document = createDocument();
+		document.appendChild(rootElement);
+		XmlHelper.writeDocument(document, file);
+	}
+
+	/**
+	 * Returns a new document instance
+	 * 
+	 * @return a new document instance
+	 * 
+	 * @throws RuntimeException
+	 *             if something went wrong while creating the XML configuration
+	 */
+	public static Document createDocument() throws RuntimeException {
+		try {
+
+			DocumentBuilderFactory dbfac = DocumentBuilderFactory.newInstance();
+			DocumentBuilder docBuilder = dbfac.newDocumentBuilder();
+			Document document = docBuilder.newDocument();
+
+			return document;
+
+		} catch (DOMException e) {
+			throw new XmlException("Failed to create Document: " + e.getLocalizedMessage(), e);
+		} catch (ParserConfigurationException e) {
+			throw new XmlException("Failed to create Document: " + e.getLocalizedMessage(), e);
+		}
+	}
+}