Java example source code file (TransformEnvelopedSignature.java)

This example Java source code file (TransformEnvelopedSignature.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

dom, element, envelopednodefilter, node, outputstream, string, transformationexception, transformenvelopedsignature, transformspi, xmlsignatureinput

The TransformEnvelopedSignature.java Java example source code

/*
 * reserved comment block
 * DO NOT REMOVE OR ALTER!
 */
/**
 * 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.
 */
package com.sun.org.apache.xml.internal.security.transforms.implementations;

import java.io.OutputStream;

import com.sun.org.apache.xml.internal.security.signature.NodeFilter;
import com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput;
import com.sun.org.apache.xml.internal.security.transforms.Transform;
import com.sun.org.apache.xml.internal.security.transforms.TransformSpi;
import com.sun.org.apache.xml.internal.security.transforms.TransformationException;
import com.sun.org.apache.xml.internal.security.transforms.Transforms;
import com.sun.org.apache.xml.internal.security.utils.Constants;
import com.sun.org.apache.xml.internal.security.utils.XMLUtils;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * Implements the <CODE>http://www.w3.org/2000/09/xmldsig#enveloped-signature
 * transform.
 *
 * @author Christian Geuer-Pollmann
 */
public class TransformEnvelopedSignature extends TransformSpi {

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

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

    /**
     * @inheritDoc
     */
    protected XMLSignatureInput enginePerformTransform(
        XMLSignatureInput input, OutputStream os, Transform transformObject
    ) throws TransformationException {
        /**
         * If the actual input is an octet stream, then the application MUST
         * convert the octet stream to an XPath node-set suitable for use by
         * Canonical XML with Comments. (A subsequent application of the
         * REQUIRED Canonical XML algorithm would strip away these comments.)
         *
         * ...
         *
         * The evaluation of this expression includes all of the document's nodes
         * (including comments) in the node-set representing the octet stream.
         */

        Node signatureElement = transformObject.getElement();

        signatureElement = searchSignatureElement(signatureElement);
        input.setExcludeNode(signatureElement);
        input.addNodeFilter(new EnvelopedNodeFilter(signatureElement));
        return input;
    }

    /**
     * @param signatureElement
     * @return the node that is the signature
     * @throws TransformationException
     */
    private static Node searchSignatureElement(Node signatureElement)
        throws TransformationException {
        boolean found = false;

        while (true) {
            if (signatureElement == null
                || signatureElement.getNodeType() == Node.DOCUMENT_NODE) {
                break;
            }
            Element el = (Element) signatureElement;
            if (el.getNamespaceURI().equals(Constants.SignatureSpecNS)
                && el.getLocalName().equals(Constants._TAG_SIGNATURE)) {
                found = true;
                break;
            }

            signatureElement = signatureElement.getParentNode();
        }

        if (!found) {
            throw new TransformationException(
                "transform.envelopedSignatureTransformNotInSignatureElement");
        }
        return signatureElement;
    }

    static class EnvelopedNodeFilter implements NodeFilter {

        Node exclude;

        EnvelopedNodeFilter(Node n) {
            exclude = n;
        }

        public int isNodeIncludeDO(Node n, int level) {
            if (n == exclude) {
                return -1;
            }
            return 1;
        }

        /**
         * @see com.sun.org.apache.xml.internal.security.signature.NodeFilter#isNodeInclude(org.w3c.dom.Node)
         */
        public int isNodeInclude(Node n) {
            if (n == exclude || XMLUtils.isDescendantOrSelf(exclude, n)) {
                return -1;
            }
            return 1;
            //return !XMLUtils.isDescendantOrSelf(exclude,n);
        }
    }
}