/*
    * Copyright 2002,2004 The Apache Software Foundation.
    *
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *      http://www.apache.org/licenses/LICENSE-2.0
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.apache.commons.jelly.tags.validate;
  
  import java.io.ByteArrayInputStream;
  import java.io.File;
  import java.io.FileInputStream;
  import java.io.FileNotFoundException;
  import java.io.InputStream;
  import java.io.IOException;
  
  import org.apache.commons.jelly.JellyTagException;
  import org.apache.commons.jelly.MissingAttributeException;
  import org.apache.commons.jelly.TagSupport;
  import org.apache.commons.jelly.XMLOutput;
  import org.apache.commons.jelly.util.ClassLoaderUtils;
  import org.iso_relax.verifier.Schema;
  import org.iso_relax.verifier.Verifier;
  import org.iso_relax.verifier.VerifierConfigurationException;
  import org.iso_relax.verifier.VerifierFactory;
  import org.xml.sax.SAXException;
  
  /***
   * This tag creates a new Verifier of a schema as a variable
   * so that it can be used by a <validate> tag.
   *
   * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
   * @version $Revision: 155420 $
   */
  public class VerifierTag extends TagSupport {
  
      /*** the variable name to export the Verifier as */
      private String var;
  
      /*** The URI to load the schema from */
      private String uri;
  
      /*** The file to load the schema from */
      private File file;
  
      /*** The system ID to use when parsing the schema */
      private String systemId;
  
      /*** The factory used to create new schema verifier objects */
      private VerifierFactory factory;
  
      // Tag interface
      //-------------------------------------------------------------------------
      public void doTag(final XMLOutput output) throws MissingAttributeException, JellyTagException {
          if ( var == null ) {
              throw new MissingAttributeException("var");
          }
  
          InputStream in = null;
          if ( uri != null ) {
              in = context.getResourceAsStream( uri );
              if ( in == null ) {
                  throw new JellyTagException( "Could not find resource for uri: " + uri );
              }
          } else if (file != null) {
              try {
                  in = new FileInputStream(file);
              } catch (FileNotFoundException e) {
                  throw new JellyTagException(e);
              }
          } else {
              String text = getBodyText();
              in = new ByteArrayInputStream( text.getBytes() );
          }
  
          Verifier verifier = null;
          try {
              Schema schema = null;
              if (systemId != null) {
                  schema = getFactory().compileSchema(in, systemId);
              }
              else if ( uri != null ) {
                  schema = getFactory().compileSchema(in, uri);
              }
              else{
                  schema = getFactory().compileSchema(in);
              }
  
              if ( schema == null ) {
                  throw new JellyTagException( "Could not create a valid schema" );
              }
 
             verifier = schema.newVerifier();
         }
         catch (VerifierConfigurationException e) {
             throw new JellyTagException(e);
         }
         catch (SAXException e) {
             throw new JellyTagException(e);
         }
         catch (IOException e) {
             throw new JellyTagException(e);
         }
 
         context.setVariable(var, verifier);
     }
 
     // Properties
     //-------------------------------------------------------------------------
 
     /***
      * Sets the name of the variable that will be set to the new Verifier
      *
      * @jelly:required
      */
     public void setVar(String var) {
         this.var = var;
     }
 
     /***
      * Sets the URI of the schema file to parse. If no URI and no file is
      * specified then the body of this tag is used as the source of the schema
      *
      * @jelly:optional
      */
     public void setUri(String uri) {
         this.uri = uri;
     }
 
     /***
      * Sets the {@link File} of the schema to parse. If no URI and no file is
      * specified then the body of this tag is used as the source of the schema
      *
      * @jelly:optional
      */
     public void setFile(File aFile) {
         file = aFile;
     }
 
     /***
      * Sets the system ID used when parsing the schema
      *
      * @jelly:optional
      */
     public void setSystemId(String systemId) {
         this.systemId = systemId;
     }
 
     /***
      * Sets the factory used to create new schema verifier objects.
      * If none is provided then the default MSV factory is used.
      *
      * @jelly:optional
      */
     public void setFactory(VerifierFactory factory) {
         this.factory = factory;
     }
 
     public VerifierFactory getFactory() throws JellyTagException {
         if ( factory == null ) {
             try {
                 ClassLoader loader = ClassLoaderUtils.getClassLoader(null, true, getClass());
                 factory = (VerifierFactory)loader.loadClass(
                     "com.sun.msv.verifier.jarv.TheFactoryImpl").newInstance();
             } catch (ClassNotFoundException e) {
                 throw new JellyTagException(e);
             } catch (InstantiationException e) {
                 throw new JellyTagException(e);
             } catch (IllegalAccessException e) {
                 throw new JellyTagException(e);
             }
         }
         return factory;
     }
 
     // Implementation methods
     //-------------------------------------------------------------------------
 
 
 }