Java tutorial
/* * This library is part of OpenCms - * the Open Source Content Management System * * Copyright (c) Alkacon Software GmbH (http://www.alkacon.com) * * This library 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 2.1 of the License, or (at your option) any later version. * * This library 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. * * For further information about Alkacon Software GmbH, please see the * company website: http://www.alkacon.com * * For further information about OpenCms, please see the * project website: http://www.opencms.org * * You should have received a copy of the GNU Lesser General Public * License along with this library; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ package org.opencms.setup.xml; import org.opencms.i18n.CmsEncoder; import org.opencms.i18n.CmsMessageContainer; import org.opencms.main.CmsLog; import org.opencms.util.CmsCollectionsGenericWrapper; import org.opencms.util.CmsStringUtil; import org.opencms.xml.CmsXmlException; import org.opencms.xml.CmsXmlUtils; import java.io.File; import java.io.FileNotFoundException; import java.io.FileOutputStream; import java.io.FileReader; import java.io.OutputStream; import java.io.StringReader; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import org.apache.commons.logging.Log; import org.dom4j.Attribute; import org.dom4j.Document; import org.dom4j.Element; import org.dom4j.Node; import org.xml.sax.EntityResolver; import org.xml.sax.InputSource; /** * Helper class to modify xml files.<p> * * For more info about xpath see: <br> * <ul> * <li>http://www.w3.org/TR/xpath.html</li> * <li>http://www.zvon.org/xxl/XPathTutorial/General/examples.html</li> * </ul><p> * * @since 6.1.8 */ public class CmsSetupXmlHelper { /** The log object for this class. */ private static final Log LOG = CmsLog.getLog(CmsSetupXmlHelper.class); /** Entity resolver to skip dtd validation. */ private static final EntityResolver NO_ENTITY_RESOLVER = new EntityResolver() { /** * @see org.xml.sax.EntityResolver#resolveEntity(java.lang.String, java.lang.String) */ public InputSource resolveEntity(String publicId, String systemId) { return new InputSource(new StringReader("")); } }; /** Optional base path. */ private String m_basePath; /** Document cache. */ private Map<String, Document> m_cache = new HashMap<String, Document>(); /** * Default constructor.<p> * * Uses no base path.<p> */ public CmsSetupXmlHelper() { // ignore } /** * Uses an optional base file path.<p> * * @param basePath the base file path to use; */ public CmsSetupXmlHelper(String basePath) { m_basePath = basePath; } /** * Unmarshals (reads) an XML string into a new document.<p> * * @param xml the XML code to unmarshal * * @return the generated document * * @throws CmsXmlException if something goes wrong */ public static String format(String xml) throws CmsXmlException { return CmsXmlUtils.marshal((Node) CmsXmlUtils.unmarshalHelper(xml, null), CmsEncoder.ENCODING_UTF_8); } /** * Returns the value in the given xpath of the given xml file.<p> * * @param document the xml document * @param xPath the xpath to read (should select a single node or attribute) * * @return the value in the given xpath of the given xml file, or <code>null</code> if no matching node */ public static String getValue(Document document, String xPath) { Node node = document.selectSingleNode(xPath); if (node != null) { // return the value return node.getText(); } else { return null; } } /** * Replaces a attibute's value in the given node addressed by the xPath.<p> * * @param document the document to replace the node attribute * @param xPath the xPath to the node * @param attribute the attribute to replace the value of * @param value the new value to set * * @return <code>true</code> if successful <code>false</code> otherwise */ public static boolean setAttribute(Document document, String xPath, String attribute, String value) { Node node = document.selectSingleNode(xPath); Element e = (Element) node; @SuppressWarnings("unchecked") List<Attribute> attributes = e.attributes(); for (Attribute a : attributes) { if (a.getName().equals(attribute)) { a.setValue(value); return true; } } return false; } /** * Sets the given value in all nodes identified by the given xpath of the given xml file.<p> * * If value is <code>null</code>, all nodes identified by the given xpath will be deleted.<p> * * If the node identified by the given xpath does not exists, the missing nodes will be created * (if <code>value</code> not <code>null</code>).<p> * * @param document the xml document * @param xPath the xpath to set * @param value the value to set (can be <code>null</code> for deletion) * * @return the number of successful changed or deleted nodes */ public static int setValue(Document document, String xPath, String value) { return setValue(document, xPath, value, null); } /** * Sets the given value in all nodes identified by the given xpath of the given xml file.<p> * * If value is <code>null</code>, all nodes identified by the given xpath will be deleted.<p> * * If the node identified by the given xpath does not exists, the missing nodes will be created * (if <code>value</code> not <code>null</code>).<p> * * @param document the xml document * @param xPath the xpath to set * @param value the value to set (can be <code>null</code> for deletion) * @param nodeToInsert optional, if given it will be inserted after xPath with the given value * * @return the number of successful changed or deleted nodes */ public static int setValue(Document document, String xPath, String value, String nodeToInsert) { int changes = 0; // be naive and try to find the node Iterator<Node> itNodes = CmsCollectionsGenericWrapper.<Node>list(document.selectNodes(xPath)).iterator(); // if not found if (!itNodes.hasNext()) { if (value == null) { // if no node found for deletion return 0; } // find the node creating missing nodes in the way Iterator<String> it = CmsStringUtil.splitAsList(xPath, "/", false).iterator(); Node currentNode = document; while (it.hasNext()) { String nodeName = it.next(); // if a string condition contains '/' while ((nodeName.indexOf("='") > 0) && (nodeName.indexOf("']") < 0)) { nodeName += "/" + it.next(); } Node node = currentNode.selectSingleNode(nodeName); if (node != null) { // node found currentNode = node; if (!it.hasNext()) { currentNode.setText(value); } } else if (currentNode.getNodeType() == Node.ELEMENT_NODE) { Element elem = (Element) currentNode; if (!nodeName.startsWith("@")) { elem = handleNode(elem, nodeName); if (!it.hasNext() && CmsStringUtil.isNotEmptyOrWhitespaceOnly(value)) { elem.setText(value); } } else { // if node is attribute create it with given value elem.addAttribute(nodeName.substring(1), value); } currentNode = elem; } else { // should never happen if (LOG.isDebugEnabled()) { LOG.debug(Messages.get().getBundle().key(Messages.ERR_XML_SET_VALUE_2, xPath, value)); } break; } } if (nodeToInsert == null) { // if not inserting we are done return 1; } // if inserting, we just created the insertion point, so continue itNodes = CmsCollectionsGenericWrapper.<Node>list(document.selectNodes(xPath)).iterator(); } // if found while (itNodes.hasNext()) { Node node = itNodes.next(); if (nodeToInsert == null) { // if not inserting if (value != null) { // if found, change the value node.setText(value); } else { // if node for deletion is found node.getParent().remove(node); } } else { // first create the node to insert Element parent = node.getParent(); Element elem = handleNode(parent, nodeToInsert); if (value != null) { elem.setText(value); } // get the parent element list List<Node> list = CmsCollectionsGenericWrapper.<Node>list(parent.content()); // remove the just created element list.remove(list.size() - 1); // insert it back to the right position int pos = list.indexOf(node); list.add(pos + 1, elem); // insert after } changes++; } return changes; } /** * Handles the xpath name, by creating the given node and its children.<p> * * @param parent the parent node to use * @param xpathName the xpathName, ie <code>a[@b='c'][d='e'][text()='f']</code> * * @return the new created element */ private static Element handleNode(Element parent, String xpathName) { // if node is no attribute, create a new node String childrenPart = null; String nodeName; int pos = xpathName.indexOf("["); if (pos > 0) { childrenPart = xpathName.substring(pos + 1, xpathName.length() - 1); nodeName = xpathName.substring(0, pos); } else { nodeName = xpathName; } // create node Element elem = parent.addElement(nodeName); if (childrenPart != null) { pos = childrenPart.indexOf("["); if ((pos > 0) && (childrenPart.indexOf("]") > pos)) { handleNode(elem, childrenPart); return elem; } Map<String, String> children = CmsStringUtil.splitAsMap(childrenPart, "][", "="); // handle child nodes for (Map.Entry<String, String> child : children.entrySet()) { String childName = child.getKey(); String childValue = child.getValue(); if (childValue.startsWith("'")) { childValue = childValue.substring(1); } if (childValue.endsWith("'")) { childValue = childValue.substring(0, childValue.length() - 1); } if (childName.startsWith("@")) { elem.addAttribute(childName.substring(1), childValue); } else if (childName.equals("text()")) { elem.setText(childValue); } else if (!childName.contains("(")) { Element childElem = elem.addElement(childName); if (CmsStringUtil.isNotEmptyOrWhitespaceOnly(childValue)) { childElem.addText(childValue); } } } } return elem; } /** * Discards the changes in the given file.<p> * * @param xmlFilename the xml config file (could be relative to the base path) */ public void flush(String xmlFilename) { m_cache.remove(xmlFilename); } /** * Discards the changes in all files.<p> */ public void flushAll() { m_cache.clear(); } /** * Returns the base file Path.<p> * * @return the base file Path */ public String getBasePath() { return m_basePath; } /** * Returns the document for the given filename.<p> * It can be new read or come from the document cache.<p> * * @param xmlFilename the filename to read * * @return the document for the given filename * * @throws CmsXmlException if something goes wrong while reading */ public Document getDocument(String xmlFilename) throws CmsXmlException { // try to get it from the cache Document document = m_cache.get(xmlFilename); if (document == null) { try { document = CmsXmlUtils.unmarshalHelper(new InputSource(new FileReader(getFile(xmlFilename))), NO_ENTITY_RESOLVER); } catch (FileNotFoundException e) { throw new CmsXmlException(new CmsMessageContainer(null, e.toString())); } // cache the doc m_cache.put(xmlFilename, document); } return document; } /** * Returns the value in the given xpath of the given xml file.<p> * * @param xmlFilename the xml config file (could be relative to the base path) * @param xPath the xpath to read (should select a single node or attribute) * * @return the value in the given xpath of the given xml file, or <code>null</code> if no matching node * * @throws CmsXmlException if something goes wrong while reading */ public String getValue(String xmlFilename, String xPath) throws CmsXmlException { return getValue(getDocument(xmlFilename), xPath); } /** * Replaces a attibute's value in the given node addressed by the xPath.<p> * * @param xmlFilename the xml file name to get the document from * @param xPath the xPath to the node * @param attribute the attribute to replace the value of * @param value the new value to set * * @return <code>true</code> if successful <code>false</code> otherwise * * @throws CmsXmlException if the xml document coudn't be read */ public boolean setAttribute(String xmlFilename, String xPath, String attribute, String value) throws CmsXmlException { return setAttribute(getDocument(xmlFilename), xPath, attribute, value); } /** * Sets the given value in all nodes identified by the given xpath of the given xml file.<p> * * If value is <code>null</code>, all nodes identified by the given xpath will be deleted.<p> * * If the node identified by the given xpath does not exists, the missing nodes will be created * (if <code>value</code> not <code>null</code>).<p> * * @param xmlFilename the xml config file (could be relative to the base path) * @param xPath the xpath to set * @param value the value to set (can be <code>null</code> for deletion) * * @return the number of successful changed or deleted nodes * * @throws CmsXmlException if something goes wrong */ public int setValue(String xmlFilename, String xPath, String value) throws CmsXmlException { return setValue(getDocument(xmlFilename), xPath, value, null); } /** * Sets the given value in all nodes identified by the given xpath of the given xml file.<p> * * If value is <code>null</code>, all nodes identified by the given xpath will be deleted.<p> * * If the node identified by the given xpath does not exists, the missing nodes will be created * (if <code>value</code> not <code>null</code>).<p> * * @param xmlFilename the xml config file (could be relative to the base path) * @param xPath the xpath to set * @param value the value to set (can be <code>null</code> for deletion) * @param nodeToInsert optional, if given it will be inserted after xPath with the given value * * @return the number of successful changed or deleted nodes * * @throws CmsXmlException if something goes wrong */ public int setValue(String xmlFilename, String xPath, String value, String nodeToInsert) throws CmsXmlException { return setValue(getDocument(xmlFilename), xPath, value, nodeToInsert); } /** * Writes the given file back to disk.<p> * * @param xmlFilename the xml config file (could be relative to the base path) * * @throws CmsXmlException if something wrong while writing */ public void write(String xmlFilename) throws CmsXmlException { // try to get it from the cache Document document = m_cache.get(xmlFilename); if (document != null) { try { OutputStream out = new FileOutputStream(getFile(xmlFilename)); CmsXmlUtils.marshal(document, out, CmsEncoder.ENCODING_UTF_8); } catch (FileNotFoundException e) { throw new CmsXmlException(new CmsMessageContainer(null, e.toString())); } } } /** * Flushes all cached documents.<p> * * @throws CmsXmlException if something wrong while writing */ public void writeAll() throws CmsXmlException { Iterator<String> it = new ArrayList<String>(m_cache.keySet()).iterator(); while (it.hasNext()) { String filename = it.next(); write(filename); } } /** * Returns a file from a given filename.<p> * * @param xmlFilename the file name * * @return the file */ private File getFile(String xmlFilename) { File file = new File(m_basePath + xmlFilename); if (!file.exists() || !file.canRead()) { file = new File(xmlFilename); } return file; } }