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/**

 * Licensed to the Apache Software Foundation (ASF) under one

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 * 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

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package com.sun.org.apache.xml.internal.security.transforms;

import java.io.IOException;

import java.io.OutputStream;

import java.util.concurrent.ConcurrentHashMap;

import java.util.Map;

import javax.xml.parsers.ParserConfigurationException;

import com.sun.org.apache.xml.internal.security.c14n.CanonicalizationException;

import com.sun.org.apache.xml.internal.security.c14n.InvalidCanonicalizerException;

import com.sun.org.apache.xml.internal.security.exceptions.AlgorithmAlreadyRegisteredException;

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.implementations.TransformBase64Decode;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14N;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14N11;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14N11_WithComments;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14NExclusive;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14NExclusiveWithComments;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformC14NWithComments;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformEnvelopedSignature;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformXPath;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformXPath2Filter;

import com.sun.org.apache.xml.internal.security.transforms.implementations.TransformXSLT;

import com.sun.org.apache.xml.internal.security.utils.Constants;

import com.sun.org.apache.xml.internal.security.utils.HelperNodeList;

import com.sun.org.apache.xml.internal.security.utils.SignatureElementProxy;

import com.sun.org.apache.xml.internal.security.utils.XMLUtils;

import org.w3c.dom.Document;

import org.w3c.dom.Element;

import org.w3c.dom.NodeList;

import org.xml.sax.SAXException;

/**

 * Implements the behaviour of the <code>ds:Transform</code> element.

 *

 * This <code>Transform</code>(Factory) class acts as the Factory and Proxy of

 * the implementing class that supports the functionality of <a

 * href=http://www.w3.org/TR/xmldsig-core/#sec-TransformAlg>a Transform

 * algorithm</a>.

 * Implements the Factory and Proxy pattern for ds:Transform algorithms.

 *

 * @author Christian Geuer-Pollmann

 * @see Transforms

 * @see TransformSpi

 */

public final class Transform extends SignatureElementProxy {

    /** {@link org.apache.commons.logging} logging facility */

    private static java.util.logging.Logger log =

        java.util.logging.Logger.getLogger(Transform.class.getName());

    /** All available Transform classes are registered here */

    private static Map<String, Class<? extends TransformSpi>> transformSpiHash =

        new ConcurrentHashMap<String, Class<? extends TransformSpi>>();

    private final TransformSpi transformSpi;

    /**

     * Generates a Transform object that implements the specified

     * <code>Transform algorithm</code> URI.

     *

     * @param doc the proxy {@link Document}

     * @param algorithmURI <code>Transform algorithm</code> URI representation,

     * such as specified in

     * <a href=http://www.w3.org/TR/xmldsig-core/#sec-TransformAlg>Transform algorithm </a>

     * @throws InvalidTransformException

     */

    public Transform(Document doc, String algorithmURI) throws InvalidTransformException {

        this(doc, algorithmURI, (NodeList)null);

    }

    /**

     * Generates a Transform object that implements the specified

     * <code>Transform algorithm</code> URI.

     *

     * @param algorithmURI <code>Transform algorithm</code> URI representation,

     * such as specified in

     * <a href=http://www.w3.org/TR/xmldsig-core/#sec-TransformAlg>Transform algorithm </a>

     * @param contextChild the child element of <code>Transform</code> element

     * @param doc the proxy {@link Document}

     * @throws InvalidTransformException

     */

    public Transform(Document doc, String algorithmURI, Element contextChild)

        throws InvalidTransformException {

        super(doc);

        HelperNodeList contextNodes = null;

        if (contextChild != null) {

            contextNodes = new HelperNodeList();

            XMLUtils.addReturnToElement(doc, contextNodes);

            contextNodes.appendChild(contextChild);

            XMLUtils.addReturnToElement(doc, contextNodes);

        }

        transformSpi = initializeTransform(algorithmURI, contextNodes);

    }

    /**

     * Constructs {@link Transform}

     *

     * @param doc the {@link Document} in which <code>Transform</code> will be

     * placed

     * @param algorithmURI URI representation of <code>Transform algorithm</code>

     * @param contextNodes the child node list of <code>Transform</code> element

     * @throws InvalidTransformException

     */

    public Transform(Document doc, String algorithmURI, NodeList contextNodes)

        throws InvalidTransformException {

        super(doc);

        transformSpi = initializeTransform(algorithmURI, contextNodes);

    }

    /**

     * @param element <code>ds:Transform</code> element

     * @param BaseURI the URI of the resource where the XML instance was stored

     * @throws InvalidTransformException

     * @throws TransformationException

     * @throws XMLSecurityException

     */

    public Transform(Element element, String BaseURI)

        throws InvalidTransformException, TransformationException, XMLSecurityException {

        super(element, BaseURI);

        // retrieve Algorithm Attribute from ds:Transform

        String algorithmURI = element.getAttributeNS(null, Constants._ATT_ALGORITHM);

        if (algorithmURI == null || algorithmURI.length() == 0) {

            Object exArgs[] = { Constants._ATT_ALGORITHM, Constants._TAG_TRANSFORM };

            throw new TransformationException("xml.WrongContent", exArgs);

        }

        Class<? extends TransformSpi> transformSpiClass = transformSpiHash.get(algorithmURI);

        if (transformSpiClass == null) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException("signature.Transform.UnknownTransform", exArgs);

        }

        try {

            transformSpi = transformSpiClass.newInstance();

        } catch (InstantiationException ex) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException(

                "signature.Transform.UnknownTransform", exArgs, ex

            );

        } catch (IllegalAccessException ex) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException(

                "signature.Transform.UnknownTransform", exArgs, ex

            );

        }

    }

    /**

     * Registers implementing class of the Transform algorithm with algorithmURI

     *

     * @param algorithmURI algorithmURI URI representation of <code>Transform algorithm</code>

     * @param implementingClass <code>implementingClass</code> the implementing

     * class of {@link TransformSpi}

     * @throws AlgorithmAlreadyRegisteredException if specified algorithmURI

     * is already registered

     */

    @SuppressWarnings("unchecked")

    public static void register(String algorithmURI, String implementingClass)

        throws AlgorithmAlreadyRegisteredException, ClassNotFoundException,

            InvalidTransformException {

        // are we already registered?

        Class<? extends TransformSpi> transformSpi = transformSpiHash.get(algorithmURI);

        if (transformSpi != null) {

            Object exArgs[] = { algorithmURI, transformSpi };

            throw new AlgorithmAlreadyRegisteredException("algorithm.alreadyRegistered", exArgs);

        }

        Class<? extends TransformSpi> transformSpiClass =

            (Class<? extends TransformSpi>)

                ClassLoaderUtils.loadClass(implementingClass, Transform.class);

        transformSpiHash.put(algorithmURI, transformSpiClass);

    }

    /**

     * Registers implementing class of the Transform algorithm with algorithmURI

     *

     * @param algorithmURI algorithmURI URI representation of <code>Transform algorithm</code>

     * @param implementingClass <code>implementingClass</code> the implementing

     * class of {@link TransformSpi}

     * @throws AlgorithmAlreadyRegisteredException if specified algorithmURI

     * is already registered

     */

    public static void register(String algorithmURI, Class<? extends TransformSpi> implementingClass)

        throws AlgorithmAlreadyRegisteredException {

        // are we already registered?

        Class<? extends TransformSpi> transformSpi = transformSpiHash.get(algorithmURI);

        if (transformSpi != null) {

            Object exArgs[] = { algorithmURI, transformSpi };

            throw new AlgorithmAlreadyRegisteredException("algorithm.alreadyRegistered", exArgs);

        }

        transformSpiHash.put(algorithmURI, implementingClass);

    }

    /**

     * This method registers the default algorithms.

     */

    public static void registerDefaultAlgorithms() {

        transformSpiHash.put(

            Transforms.TRANSFORM_BASE64_DECODE, TransformBase64Decode.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N_OMIT_COMMENTS, TransformC14N.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N_WITH_COMMENTS, TransformC14NWithComments.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N11_OMIT_COMMENTS, TransformC14N11.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N11_WITH_COMMENTS, TransformC14N11_WithComments.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N_EXCL_OMIT_COMMENTS, TransformC14NExclusive.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_C14N_EXCL_WITH_COMMENTS, TransformC14NExclusiveWithComments.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_XPATH, TransformXPath.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_ENVELOPED_SIGNATURE, TransformEnvelopedSignature.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_XSLT, TransformXSLT.class

        );

        transformSpiHash.put(

            Transforms.TRANSFORM_XPATH2FILTER, TransformXPath2Filter.class

        );

    }

    /**

     * Returns the URI representation of Transformation algorithm

     *

     * @return the URI representation of Transformation algorithm

     */

    public String getURI() {

        return this._constructionElement.getAttributeNS(null, Constants._ATT_ALGORITHM);

    }

    /**

     * Transforms the input, and generates {@link XMLSignatureInput} as output.

     *

     * @param input input {@link XMLSignatureInput} which can supplied Octet

     * Stream and NodeSet as Input of Transformation

     * @return the {@link XMLSignatureInput} class as the result of

     * transformation

     * @throws CanonicalizationException

     * @throws IOException

     * @throws InvalidCanonicalizerException

     * @throws TransformationException

     */

    public XMLSignatureInput performTransform(XMLSignatureInput input)

        throws IOException, CanonicalizationException,

               InvalidCanonicalizerException, TransformationException {

        return performTransform(input, null);

    }

    /**

     * Transforms the input, and generates {@link XMLSignatureInput} as output.

     *

     * @param input input {@link XMLSignatureInput} which can supplied Octect

     * Stream and NodeSet as Input of Transformation

     * @param os where to output the result of the last transformation

     * @return the {@link XMLSignatureInput} class as the result of

     * transformation

     * @throws CanonicalizationException

     * @throws IOException

     * @throws InvalidCanonicalizerException

     * @throws TransformationException

     */

    public XMLSignatureInput performTransform(

        XMLSignatureInput input, OutputStream os

    ) throws IOException, CanonicalizationException,

        InvalidCanonicalizerException, TransformationException {

        XMLSignatureInput result = null;

        try {

            result = transformSpi.enginePerformTransform(input, os, this);

        } catch (ParserConfigurationException ex) {

            Object exArgs[] = { this.getURI(), "ParserConfigurationException" };

            throw new CanonicalizationException(

                "signature.Transform.ErrorDuringTransform", exArgs, ex);

        } catch (SAXException ex) {

            Object exArgs[] = { this.getURI(), "SAXException" };

            throw new CanonicalizationException(

                "signature.Transform.ErrorDuringTransform", exArgs, ex);

        }

        return result;

    }

    /** @inheritDoc */

    public String getBaseLocalName() {

        return Constants._TAG_TRANSFORM;

    }

    /**

     * Initialize the transform object.

     */

    private TransformSpi initializeTransform(String algorithmURI, NodeList contextNodes)

        throws InvalidTransformException {

        this._constructionElement.setAttributeNS(null, Constants._ATT_ALGORITHM, algorithmURI);

        Class<? extends TransformSpi> transformSpiClass = transformSpiHash.get(algorithmURI);

        if (transformSpiClass == null) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException("signature.Transform.UnknownTransform", exArgs);

        }

        TransformSpi newTransformSpi = null;

        try {

            newTransformSpi = transformSpiClass.newInstance();

        } catch (InstantiationException ex) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException(

                "signature.Transform.UnknownTransform", exArgs, ex

            );

        } catch (IllegalAccessException ex) {

            Object exArgs[] = { algorithmURI };

            throw new InvalidTransformException(

                "signature.Transform.UnknownTransform", exArgs, ex

            );

        }

        if (log.isLoggable(java.util.logging.Level.FINE)) {

            log.log(java.util.logging.Level.FINE, "Create URI \"" + algorithmURI + "\" class \""

                      + newTransformSpi.getClass() + "\"");

            log.log(java.util.logging.Level.FINE, "The NodeList is " + contextNodes);

        }

        // give it to the current document

        if (contextNodes != null) {

            for (int i = 0; i < contextNodes.getLength(); i++) {

                this._constructionElement.appendChild(contextNodes.item(i).cloneNode(true));

            }

        }

        return newTransformSpi;

    }

}