package org.apache.velocity.runtime.directive;
   
   /*
    * Licensed to the Apache Software Foundation (ASF) under one
    * or more contributor license agreements.  See the NOTICE file
    * distributed with this work for additional information
    * regarding copyright ownership.  The ASF licenses this file
    * to you 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.    
   */
  
  import java.io.IOException;
  import java.io.StringReader;
  import java.io.Writer;
  
  import org.apache.velocity.context.EvaluateContext;
  import org.apache.velocity.context.InternalContextAdapter;
  import org.apache.velocity.context.InternalContextAdapterImpl;
  import org.apache.velocity.exception.MethodInvocationException;
  import org.apache.velocity.exception.ParseErrorException;
  import org.apache.velocity.exception.ResourceNotFoundException;
  import org.apache.velocity.exception.TemplateInitException;
  import org.apache.velocity.runtime.RuntimeServices;
  import org.apache.velocity.runtime.parser.ParseException;
  import org.apache.velocity.runtime.parser.ParserTreeConstants;
  import org.apache.velocity.runtime.parser.node.Node;
  import org.apache.velocity.runtime.parser.node.SimpleNode;
  import org.apache.velocity.util.introspection.Info;
  
  /**
   * Evaluates the directive argument as a VTL string, using the existing
   * context.
   *
   * @author <a href="mailto:wglass@apache.org">Will Glass-Husain</a>
   * @version $Id: Evaluate.java 737544 2009-01-25 17:42:08Z nbubna $
   * @since 1.6
   */
  public class Evaluate extends Directive
  {
  
      /**
       * Return name of this directive.
       * @return The name of this directive.
       */
      public String getName()
      {
          return "evaluate";
      }
  
      /**
       * Return type of this directive.
       * @return The type of this directive.
       */
      public int getType()
      {
          return LINE;
      }
  
      /**
       * Initialize and check arguments.
       * @param rs
       * @param context
       * @param node
       * @throws TemplateInitException
       */
      public void init(RuntimeServices rs, InternalContextAdapter context,
                       Node node)
          throws TemplateInitException
      {
          super.init( rs, context, node );
  
          /**
           * Check that there is exactly one argument and it is a string or reference.
           */  
          
          int argCount = node.jjtGetNumChildren();
          if (argCount == 0)
          {
              throw new TemplateInitException(
                      "#" + getName() + "() requires exactly one argument", 
                      context.getCurrentTemplateName(),
                      node.getColumn(),
                      node.getLine());            
          }
          if (argCount > 1)
          {
              /* 
               * use line/col of second argument
               */
             
             throw new TemplateInitException(
                     "#" + getName() + "() requires exactly one argument", 
                     context.getCurrentTemplateName(),
                     node.jjtGetChild(1).getColumn(),
                     node.jjtGetChild(1).getLine());
         }
         
         Node childNode = node.jjtGetChild(0);
         if ( childNode.getType() !=  ParserTreeConstants.JJTSTRINGLITERAL &&
              childNode.getType() !=  ParserTreeConstants.JJTREFERENCE )
         {
            throw new TemplateInitException(
                    "#" + getName() + "()  argument must be a string literal or reference", 
                    context.getCurrentTemplateName(),
                    childNode.getColumn(),
                    childNode.getLine());
         }
     }
     
     /**
      * Evaluate the argument, convert to a String, and evaluate again 
      * (with the same context).
      * @param context
      * @param writer
      * @param node
      * @return True if the directive rendered successfully.
      * @throws IOException
      * @throws ResourceNotFoundException
      * @throws ParseErrorException 
      * @throws MethodInvocationException
      */
     public boolean render(InternalContextAdapter context, Writer writer,
             Node node) throws IOException, ResourceNotFoundException,
             ParseErrorException, MethodInvocationException
     {
 
         /*
          * Evaluate the string with the current context.  We know there is
          * exactly one argument and it is a string or reference.
          */
         
         Object value = node.jjtGetChild(0).value( context );
         String sourceText;
         if ( value != null )
         {
             sourceText = value.toString();
         } 
         else
         {
             sourceText = "";
         }
         
         /*
          * The new string needs to be parsed since the text has been dynamically generated.
          */
         String templateName = context.getCurrentTemplateName();
         SimpleNode nodeTree = null;
 
         try
         {
             nodeTree = rsvc.parse(new StringReader(sourceText), templateName, false);
         }
         catch (ParseException pex)
         {
             // use the line/column from the template
             Info info = new Info( templateName, node.getLine(), node.getColumn() );
             throw  new ParseErrorException( pex.getMessage(), info );
         }
         catch (TemplateInitException pex)
         {
             Info info = new Info( templateName, node.getLine(), node.getColumn() );
             throw  new ParseErrorException( pex.getMessage(), info );
         }
 
         /*
          * now we want to init and render.  Chain the context
          * to prevent any changes to the current context.
          */
 
         if (nodeTree != null)
         {
             InternalContextAdapter ica = new EvaluateContext(context, rsvc);
 
             ica.pushCurrentTemplateName( templateName );
 
             try
             {
                 try
                 {
                     nodeTree.init( ica, rsvc );
                 }
                 catch (TemplateInitException pex)
                 {
                     Info info = new Info( templateName, node.getLine(), node.getColumn() );
                     throw  new ParseErrorException( pex.getMessage(), info );
                 }
 
                 try 
                 {
                     /*
                      *  now render, and let any exceptions fly
                      */
                     nodeTree.render( ica, writer );
                 }
                 catch (ParseErrorException pex)
                 {
                     // convert any parsing errors to the correct line/col
                     Info info = new Info( templateName, node.getLine(), node.getColumn() );
                     throw  new ParseErrorException( pex.getMessage(), info );
                 }
             }
             finally
             {
                 ica.popCurrentTemplateName();
             }
 
             return true;
         }
 
         
         return false;
     }
 
 }