winery/org.eclipse.winery.common/src/main/java/org/eclipse/winery/common/TOSCADocumentBuilderFactory.java

   1 /*******************************************************************************
   2  * Copyright (c) 2013 University of Stuttgart.
   3  * All rights reserved. This program and the accompanying materials
   4  * are made available under the terms of the Eclipse Public License v1.0
   5  * and the Apache License 2.0 which both accompany this distribution,
   6  * and are available at http://www.eclipse.org/legal/epl-v10.html
   7  * and http://www.apache.org/licenses/LICENSE-2.0
   8  *
   9  * Contributors:
  10  *     Oliver Kopp - initial API and implementation
  11  *******************************************************************************/
  12 package org.eclipse.winery.common;
  13
  14 import java.net.URL;
  15
  16 import javax.xml.XMLConstants;
  17 import javax.xml.parsers.DocumentBuilder;
  18 import javax.xml.parsers.DocumentBuilderFactory;
  19 import javax.xml.parsers.ParserConfigurationException;
  20 import javax.xml.validation.Schema;
  21 import javax.xml.validation.SchemaFactory;
  22
  23 import org.slf4j.Logger;
  24 import org.slf4j.LoggerFactory;
  25 import org.xml.sax.SAXException;
  26
  27 /**
  28  * Class to produce DocumentBuilders with a pre-loaded TOSCA XSD.
  29  *
  30  * In a separate class as TOSCA XSD loading takes a few seconds
  31  */
  32 public class TOSCADocumentBuilderFactory {
  33
  34         private static final Logger logger = LoggerFactory.getLogger(TOSCADocumentBuilderFactory.class);
  35
  36         public static final TOSCADocumentBuilderFactory INSTANCE = new TOSCADocumentBuilderFactory();
  37         private final DocumentBuilderFactory factory;
  38
  39
  40         public TOSCADocumentBuilderFactory() {
  41                 this.factory = DocumentBuilderFactory.newInstance();
  42
  43                 this.factory.setNamespaceAware(true);
  44
  45                 // we do not need DTD validation
  46                 this.factory.setValidating(false);
  47
  48                 // we do XSD validation
  49                 SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI);
  50                 Schema schema;
  51                 URL resource = this.getClass().getResource("/TOSCA-v1.0.xsd");
  52                 try {
  53                         // takes a few seconds to load
  54                         schema = schemaFactory.newSchema(resource);
  55                         this.factory.setSchema(schema);
  56                 } catch (SAXException e) {
  57                         // TODO: load xml.xsd in offline mode
  58                         TOSCADocumentBuilderFactory.logger.error("Schema could not be initalized", e);
  59                         TOSCADocumentBuilderFactory.logger.debug("We continue nevertheless to enable offline usage");
  60                 }
  61         }
  62
  63         public DocumentBuilder getTOSCADocumentBuilder() {
  64                 DocumentBuilder db;
  65                 try {
  66                         db = this.factory.newDocumentBuilder();
  67                 } catch (ParserConfigurationException e) {
  68                         throw new IllegalStateException("document builder could not be initalized", e);
  69                 }
  70                 return db;
  71         }
  72
  73 }