/*
 * Copyright  1999-2004 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 com.sun.org.apache.xml.internal.security.transforms.implementations;



import java.io.OutputStream;

import com.sun.org.apache.xml.internal.security.c14n.CanonicalizationException;
import com.sun.org.apache.xml.internal.security.c14n.implementations.Canonicalizer20010315ExclOmitComments;
import com.sun.org.apache.xml.internal.security.exceptions.XMLSecurityException;
import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;
import com.sun.org.apache.xml.internal.security.transforms.TransformSpi;
import com.sun.org.apache.xml.internal.security.transforms.Transforms;
import com.sun.org.apache.xml.internal.security.transforms.params.InclusiveNamespaces;
import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
import org.w3c.dom.Element;


/**
 * Class TransformC14NExclusive
 *
 * @author $Author: raul $
 * @version $Revision: 1.11 $
 */
public class TransformC14NExclusive extends TransformSpi {

   /** Field implementedTransformURI */
   public static final String implementedTransformURI =
      Transforms.TRANSFORM_C14N_EXCL_OMIT_COMMENTS;


   /**
    * Method engineGetURI
    *
    * @inheritDoc 
    */
   protected String engineGetURI() {
      return implementedTransformURI;
   }

   /**
    * Method enginePerformTransform
    *
    * @param input
    * @return the transformed of the input
    * @throws CanonicalizationException
    */
   protected XMLSignatureInput enginePerformTransform(XMLSignatureInput input)
           throws CanonicalizationException {
   	    return enginePerformTransform(input,null);
   }
    protected XMLSignatureInput enginePerformTransform(XMLSignatureInput input,OutputStream os)
    throws CanonicalizationException {
      try {
         String inclusiveNamespaces = null;

         if (this._transformObject
                 .length(InclusiveNamespaces
                    .ExclusiveCanonicalizationNamespace, InclusiveNamespaces
                    ._TAG_EC_INCLUSIVENAMESPACES) == 1) {
            Element inclusiveElement =
                XMLUtils.selectNode(
               this._transformObject.getElement().getFirstChild(),
                  InclusiveNamespaces.ExclusiveCanonicalizationNamespace,
                  InclusiveNamespaces._TAG_EC_INCLUSIVENAMESPACES,0);

            inclusiveNamespaces = new InclusiveNamespaces(inclusiveElement,
                    this._transformObject.getBaseURI()).getInclusiveNamespaces();
         }

         Canonicalizer20010315ExclOmitComments c14n =
            new Canonicalizer20010315ExclOmitComments();
         if (os!=null) {
            c14n.setWriter(os);
         }
         byte []result;
         input.setNeedsToBeExpanded(true);
         result =c14n.engineCanonicalize(input, inclusiveNamespaces);
              
         XMLSignatureInput output=new XMLSignatureInput(result);
         if (os!=null) {
            output.setOutputStream(os);
         }
         return output;      
      } catch (XMLSecurityException ex) {
         throw new CanonicalizationException("empty", ex);
      } 
   }
}