1 /*
   2  * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package com.sun.tools.internal.xjc;
  27 
  28 import java.net.URL;
  29 
  30 import javax.xml.validation.Schema;
  31 import javax.xml.validation.SchemaFactory;
  32 import javax.xml.validation.ValidatorHandler;
  33 
  34 import com.sun.xml.internal.bind.v2.util.XmlFactory;
  35 import javax.xml.XMLConstants;
  36 import org.xml.sax.SAXException;
  37 
  38 import static com.sun.xml.internal.bind.v2.util.XmlFactory.allowExternalAccess;
  39 
  40 /**
  41  * Wraps a JAXP {@link Schema} object and lazily instantiate it.
  42  *
  43  * This object is thread-safe. There should be only one instance of
  44  * this for the whole VM.
  45  *
  46  * @author Kohsuke Kawaguchi
  47  */
  48 public final class SchemaCache {
  49 
  50     private Schema schema;
  51 
  52     private final URL source;
  53 
  54     public SchemaCache(URL source) {
  55         this.source = source;
  56     }
  57 
  58     public ValidatorHandler newValidator() {
  59         synchronized(this) {
  60             if(schema==null) {
  61                 try {
  62                     // do not disable secure processing - these are well-known schemas
  63                     SchemaFactory sf = XmlFactory.createSchemaFactory(XMLConstants.W3C_XML_SCHEMA_NS_URI, false);
  64                     schema = allowExternalAccess(sf, "file", false).newSchema(source);
  65                 } catch (SAXException e) {
  66                     // we make sure that the schema is correct before we ship.
  67                     throw new AssertionError(e);
  68                 }
  69             }
  70         }
  71 
  72         ValidatorHandler handler = schema.newValidatorHandler();
  73         return handler;
  74     }
  75 
  76 }