//
   //  ========================================================================
   //  Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd.
   //  ------------------------------------------------------------------------
   //  All rights reserved. This program and the accompanying materials
   //  are made available under the terms of the Eclipse Public License v1.0
   //  and Apache License v2.0 which accompanies this distribution.
   //
   //      The Eclipse Public License is available at
  //      http://www.eclipse.org/legal/epl-v10.html
  //
  //      The Apache License v2.0 is available at
  //      http://www.opensource.org/licenses/apache2.0.php
  //
  //  You may elect to redistribute this code under either of these licenses.
  //  ========================================================================
  //
  
  package org.eclipse.jetty.apache.jsp;
  
  import java.io.IOException;
  import java.net.URL;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.List;
  
  import javax.servlet.ServletContext;
  
  import org.apache.jasper.servlet.JasperInitializer;
  import org.apache.jasper.servlet.TldPreScanned;
  import org.apache.jasper.servlet.TldScanner;
  import org.eclipse.jetty.util.log.Log;
  import org.eclipse.jetty.util.log.Logger;
  import org.xml.sax.SAXException;
  
  /**
   * JettyJasperInitializer
   */
  public class JettyJasperInitializer extends JasperInitializer
  {
     private static final Logger LOG = Log.getLogger(JettyJasperInitializer.class);
      
      /**
       * NullTldScanner
       *
       * Does nothing. Used when we can tell that all jsps have been precompiled, in which case
       * the tlds are not needed.
       */
      private final class NullTldScanner extends TldScanner
      {
          /**
           * @param context
           * @param namespaceAware
           * @param validation
           * @param blockExternal
           */
          private NullTldScanner(ServletContext context, boolean namespaceAware, boolean validation, boolean blockExternal)
          {
              super(context, namespaceAware, validation, blockExternal);
          }
  
          /**
           * @see org.apache.jasper.servlet.TldScanner#scan()
           */
          @Override
          public void scan() throws IOException, SAXException
          {
              return; //do nothing
          }
  
          /**
           * @see org.apache.jasper.servlet.TldScanner#getListeners()
           */
          @Override
          public List<String> getListeners()
          {
              return Collections.emptyList();
          }
  
          /**
           * @see org.apache.jasper.servlet.TldScanner#scanJars()
           */
          @Override
          public void scanJars()
          {
             return; //do nothing
          }
      }
  
      /**
       * Make a TldScanner, and prefeed it the tlds that have already been discovered in jar files
       * by the MetaInfConfiguration.
       */
      @Override
      public TldScanner newTldScanner(ServletContext context, boolean namespaceAware, boolean validate, boolean blockExternal)
      {  
          String tmp = context.getInitParameter("org.eclipse.jetty.jsp.precompiled");
          if (tmp!=null && !tmp.equals("") && Boolean.valueOf(tmp))
          {
             if (LOG.isDebugEnabled()) LOG.debug("Jsp precompilation detected");
             return new NullTldScanner(context, namespaceAware, validate, blockExternal);
         }
         
         Collection<URL> tldUrls = (Collection<URL>)context.getAttribute("org.eclipse.jetty.tlds");
         if (tldUrls != null)
         {
             if (LOG.isDebugEnabled()) LOG.debug("Tld pre-scan detected");
             return new TldPreScanned(context,namespaceAware,validate,blockExternal,tldUrls);
         }
         
         if (LOG.isDebugEnabled()) LOG.debug("Defaulting to jasper tld scanning");
         return super.newTldScanner(context, namespaceAware, validate, blockExternal);
     }
     
 
 }