/*
 * Copyright 2005 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.
 *
 */
/*
 * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
 */
/*
 * $Id: DOMCanonicalXMLC14NMethod.java 375655 2006-02-07 18:35:54Z mullan $
 */
package org.jcp.xml.dsig.internal.dom;

import javax.xml.crypto.*;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.spec.TransformParameterSpec;

import java.security.InvalidAlgorithmParameterException;

import org.apache.xml.security.c14n.Canonicalizer;
import org.apache.xml.security.c14n.InvalidCanonicalizerException;

/**
 * DOM-based implementation of CanonicalizationMethod for Canonical XML
 * (with or without comments). Uses Apache XML-Sec Canonicalizer.
 *
 * @author Sean Mullan
 */
public final class DOMCanonicalXMLC14NMethod extends ApacheCanonicalizer {

    public void init(TransformParameterSpec params)
        throws InvalidAlgorithmParameterException {
        if (params != null) {
            throw new InvalidAlgorithmParameterException("no parameters " +
                "should be specified for Canonical XML C14N algorithm");
        }
    }

    public Data transform(Data data, XMLCryptoContext xc)
	throws TransformException {

        // ignore comments if dereferencing same-document URI that requires
	// you to omit comments, even if the Transform says otherwise -
        // this is to be compliant with section 4.3.3.3 of W3C Rec.
	if (data instanceof DOMSubTreeData) {
	    DOMSubTreeData subTree = (DOMSubTreeData) data;
	    if (subTree.excludeComments()) {
                try {
                    apacheCanonicalizer = Canonicalizer.getInstance
			(CanonicalizationMethod.INCLUSIVE);
                } catch (InvalidCanonicalizerException ice) {
		    throw new TransformException
                        ("Couldn't find Canonicalizer for: " +
		         CanonicalizationMethod.INCLUSIVE + ": " +
		         ice.getMessage(), ice);
                }
	    }
	}

	return canonicalize(data, xc);
    }
}