org.eclipse.tracecompass.tmf.analysis.xml.core/src/org/eclipse/linuxtools/tmf/analysis/xml/core/module/XmlUtils.java

   1 /*******************************************************************************
   2  * Copyright (c) 2014 École Polytechnique de Montréal
   3  *
   4  * All rights reserved. This program and the accompanying materials are
   5  * made available under the terms of the Eclipse Public License v1.0 which
   6  * accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *   Geneviève Bastien - Initial API and implementation
  11  *******************************************************************************/
  12
  13 package org.eclipse.linuxtools.tmf.analysis.xml.core.module;
  14
  15 import java.io.File;
  16 import java.io.FileInputStream;
  17 import java.io.FileOutputStream;
  18 import java.io.IOException;
  19 import java.net.URL;
  20 import java.nio.channels.FileChannel;
  21 import java.util.ArrayList;
  22 import java.util.List;
  23
  24 import javax.xml.XMLConstants;
  25 import javax.xml.parsers.DocumentBuilder;
  26 import javax.xml.parsers.DocumentBuilderFactory;
  27 import javax.xml.parsers.ParserConfigurationException;
  28 import javax.xml.transform.Source;
  29 import javax.xml.transform.stream.StreamSource;
  30 import javax.xml.validation.Schema;
  31 import javax.xml.validation.SchemaFactory;
  32 import javax.xml.validation.Validator;
  33
  34 import org.eclipse.core.runtime.IPath;
  35 import org.eclipse.core.runtime.IStatus;
  36 import org.eclipse.core.runtime.Path;
  37 import org.eclipse.core.runtime.Status;
  38 import org.eclipse.jdt.annotation.NonNull;
  39 import org.eclipse.linuxtools.internal.tmf.analysis.xml.core.Activator;
  40 import org.eclipse.linuxtools.tmf.analysis.xml.core.stateprovider.TmfXmlStrings;
  41 import org.eclipse.osgi.util.NLS;
  42 import org.w3c.dom.Document;
  43 import org.w3c.dom.Element;
  44 import org.w3c.dom.Node;
  45 import org.w3c.dom.NodeList;
  46 import org.xml.sax.SAXException;
  47 import org.xml.sax.SAXParseException;
  48
  49 /**
  50  * Class containing some utilities for the XML plug-in packages: for example, it
  51  * manages the XML files and validates them
  52  *
  53  * @author Geneviève Bastien
  54  */
  55 public class XmlUtils {
  56
  57     /** Sub-directory of the plug-in where XML files are stored */
  58     private static final String XML_DIRECTORY = "xml_files"; //$NON-NLS-1$
  59
  60     /** Name of the XSD schema file */
  61     private static final String XSD = "xmlDefinition.xsd"; //$NON-NLS-1$
  62
  63     /** Make this class non-instantiable */
  64     private XmlUtils() {
  65
  66     }
  67
  68     /**
  69      * Get the path where the XML files are stored. Create it if it does not
  70      * exist
  71      *
  72      * @return path to XML files
  73      */
  74     public static IPath getXmlFilesPath() {
  75         IPath path = Activator.getDefault().getStateLocation();
  76         path = path.addTrailingSeparator().append(XML_DIRECTORY);
  77
  78         /* Check if directory exists, otherwise create it */
  79         File dir = path.toFile();
  80         if (!dir.exists() || !dir.isDirectory()) {
  81             dir.mkdirs();
  82         }
  83
  84         return path;
  85     }
  86
  87     /**
  88      * Validate the XML file input with the XSD schema
  89      *
  90      * @param xmlFile
  91      *            XML file to validate
  92      * @return True if the XML validates
  93      */
  94     public static IStatus xmlValidate(File xmlFile) {
  95         URL url = XmlUtils.class.getResource(XSD);
  96         SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
  97         Source xmlSource = new StreamSource(xmlFile);
  98         try {
  99             Schema schema = schemaFactory.newSchema(url);
 100             Validator validator = schema.newValidator();
 101             validator.validate(xmlSource);
 102         } catch (SAXParseException e) {
 103             String error = NLS.bind(Messages.XmlUtils_XmlParseError, e.getLineNumber(), e.getLocalizedMessage());
 104             Activator.logError(error);
 105             return new Status(IStatus.ERROR, Activator.PLUGIN_ID, error, e);
 106         } catch (SAXException e) {
 107             String error = NLS.bind(Messages.XmlUtils_XmlValidationError, e.getLocalizedMessage());
 108             Activator.logError(error);
 109             return new Status(IStatus.ERROR, Activator.PLUGIN_ID, error, e);
 110         } catch (IOException e) {
 111             String error = Messages.XmlUtils_XmlValidateError;
 112             Activator.logError("IO exception occurred", e); //$NON-NLS-1$
 113             return new Status(IStatus.ERROR, Activator.PLUGIN_ID, error, e);
 114         }
 115         return Status.OK_STATUS;
 116     }
 117
 118     /**
 119      * Adds an XML file to the plugin's path. The XML file should have been
 120      * validated using the {@link XmlUtils#xmlValidate(File)} method before
 121      * calling this method.
 122      *
 123      * @param fromFile
 124      *            The XML file to add
 125      * @return Whether the file was successfully added
 126      */
 127     public static IStatus addXmlFile(File fromFile) {
 128
 129         /* Copy file to path */
 130         File toFile = getXmlFilesPath().addTrailingSeparator().append(fromFile.getName()).toFile();
 131
 132         try {
 133             if (!toFile.exists()) {
 134                 toFile.createNewFile();
 135             }
 136         } catch (IOException e) {
 137             String error = Messages.XmlUtils_ErrorCopyingFile;
 138             Activator.logError(error, e);
 139             return new Status(IStatus.ERROR, Activator.PLUGIN_ID, error, e);
 140         }
 141
 142         try (FileInputStream fis = new FileInputStream(fromFile);
 143                 FileOutputStream fos = new FileOutputStream(toFile);
 144                 FileChannel source = fis.getChannel();
 145                 FileChannel destination = fos.getChannel();) {
 146             destination.transferFrom(source, 0, source.size());
 147         } catch (IOException e) {
 148             String error = Messages.XmlUtils_ErrorCopyingFile;
 149             Activator.logError(error, e);
 150             return new Status(IStatus.ERROR, Activator.PLUGIN_ID, error, e);
 151         }
 152         return Status.OK_STATUS;
 153     }
 154
 155     /**
 156      * Get only the XML element children of an XML element.
 157      *
 158      * @param parent
 159      *            The parent element to get children from
 160      * @return The list of children Element of the parent
 161      */
 162     public static List<Element> getChildElements(Element parent) {
 163         NodeList childNodes = parent.getChildNodes();
 164         List<Element> childElements = new ArrayList<>();
 165         for (int index = 0; index < childNodes.getLength(); index++) {
 166             if (childNodes.item(index).getNodeType() == Node.ELEMENT_NODE) {
 167                 childElements.add((Element) childNodes.item(index));
 168             }
 169         }
 170         return childElements;
 171     }
 172
 173     /**
 174      * Get the XML children element of an XML element, but only those of a
 175      * certain type
 176      *
 177      * @param parent
 178      *            The parent element to get the children from
 179      * @param elementTag
 180      *            The tag of the elements to return
 181      * @return The list of children {@link Element} of the parent
 182      */
 183     public static List<Element> getChildElements(Element parent, String elementTag) {
 184         /* get the state providers and find the corresponding one */
 185         NodeList nodes = parent.getElementsByTagName(elementTag);
 186         List<Element> childElements = new ArrayList<>();
 187
 188         for (int i = 0; i < nodes.getLength(); i++) {
 189             Element node = (Element) nodes.item(i);
 190             if (node.getParentNode().equals(parent)) {
 191                 childElements.add(node);
 192             }
 193         }
 194         return childElements;
 195     }
 196
 197     /**
 198      * Return the node element corresponding to the requested type in the file.
 199      *
 200      * TODO: Nothing prevents from having duplicate type -> id in a same file.
 201      * That should not be allowed. If you want an element with the same ID as
 202      * another one, it should be in a different file and we should check it at
 203      * validation time.
 204      *
 205      * @param filePath
 206      *            The absolute path to the XML file
 207      * @param elementType
 208      *            The type of top level element to search for
 209      * @param elementId
 210      *            The ID of the desired element
 211      * @return The XML element or <code>null</code> if not found
 212      */
 213     public static Element getElementInFile(String filePath, @NonNull String elementType, @NonNull String elementId) {
 214
 215         if (filePath == null) {
 216             return null;
 217         }
 218
 219         IPath path = new Path(filePath);
 220         File file = path.toFile();
 221         if (file == null || !file.exists() || !file.isFile() || !xmlValidate(file).isOK()) {
 222             return null;
 223         }
 224
 225         try {
 226             /* Load the XML File */
 227             DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();
 228             DocumentBuilder dBuilder;
 229
 230             dBuilder = dbFactory.newDocumentBuilder();
 231             Document doc = dBuilder.parse(file);
 232             doc.getDocumentElement().normalize();
 233
 234             /* get the state providers and find the corresponding one */
 235             NodeList nodes = doc.getElementsByTagName(elementType);
 236             Element foundNode = null;
 237
 238             for (int i = 0; i < nodes.getLength(); i++) {
 239                 Element node = (Element) nodes.item(i);
 240                 String id = node.getAttribute(TmfXmlStrings.ID);
 241                 if (id.equals(elementId)) {
 242                     foundNode = node;
 243                 }
 244             }
 245             return foundNode;
 246         } catch (ParserConfigurationException | SAXException | IOException e) {
 247             return null;
 248         }
 249
 250     }
 251
 252 }