/*
* Copyright 1999-2009 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 org.apache.xml.security.transforms;
import java.io.IOException;
import java.io.OutputStream;
import java.util.HashMap;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.xml.security.c14n.CanonicalizationException;
import org.apache.xml.security.c14n.InvalidCanonicalizerException;
import org.apache.xml.security.exceptions.AlgorithmAlreadyRegisteredException;
import org.apache.xml.security.exceptions.XMLSecurityException;
import org.apache.xml.security.signature.XMLSignatureInput;
import org.apache.xml.security.utils.ClassLoaderUtils;
import org.apache.xml.security.utils.Constants;
import org.apache.xml.security.utils.HelperNodeList;
import org.apache.xml.security.utils.SignatureElementProxy;
import org.apache.xml.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 org.apache.commons.logging.Log log =
org.apache.commons.logging.LogFactory.getLog(Transform.class.getName());
/** Field _alreadyInitialized */
private static boolean alreadyInitialized = false;
/** All available Transform classes are registered here */
private static HashMap transformClassHash = null;
private static HashMap transformSpiHash = new HashMap();
private TransformSpi transformSpi = null;
/**
* 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> which will be specified as parameter of
* {@link #getInstance(Document, String)}, when generated. </br>
* @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);
this._constructionElement.setAttributeNS
(null, Constants._ATT_ALGORITHM, algorithmURI);
transformSpi = getTransformSpi(algorithmURI);
if (transformSpi == null) {
Object exArgs[] = { algorithmURI };
throw new InvalidTransformException(
"signature.Transform.UnknownTransform", exArgs);
}
if (log.isDebugEnabled()) {
log.debug("Create URI \"" + algorithmURI + "\" class \""
+ transformSpi.getClass() + "\"");
log.debug("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));
}
}
}
/**
* This constructor can only be called from the {@link Transforms} object,
* so it's protected.
*
* @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);
}
transformSpi = getTransformSpi(algorithmURI);
if (transformSpi == null) {
Object exArgs[] = { algorithmURI };
throw new InvalidTransformException(
"signature.Transform.UnknownTransform", exArgs);
}
}
/**
* 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 doc the proxy {@link Document}
* @return <code>{@link Transform}</code> object
* @throws InvalidTransformException
*/
public static Transform getInstance(
Document doc, String algorithmURI) throws InvalidTransformException {
return getInstance(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}
* @return <code>{@link Transform}</code> object
* @throws InvalidTransformException
*/
public static Transform getInstance(
Document doc, String algorithmURI, Element contextChild)
throws InvalidTransformException {
HelperNodeList contextNodes = null;
if (contextChild != null) {
contextNodes = new HelperNodeList();
XMLUtils.addReturnToElement(doc, contextNodes);
contextNodes.appendChild(contextChild);
XMLUtils.addReturnToElement(doc, contextNodes);
}
return getInstance(doc, algorithmURI, contextNodes);
}
/**
* Generates a Transform object that implements the specified
* <code>Transform algorithm</code> URI.
*
* @param algorithmURI <code>Transform algorithm</code> URI form, such as
* specified in <a href=http://www.w3.org/TR/xmldsig-core/#sec-TransformAlg>
* Transform algorithm </a>
* @param contextNodes the child node list of <code>Transform</code> element
* @param doc the proxy {@link Document}
* @return <code>{@link Transform}</code> object
* @throws InvalidTransformException
*/
public static Transform getInstance(
Document doc, String algorithmURI, NodeList contextNodes)
throws InvalidTransformException {
return new Transform(doc, algorithmURI, contextNodes);
}
/**
* Initalizes for this {@link Transform}.
*/
public static void init() {
if (!alreadyInitialized) {
transformClassHash = new HashMap(10);
alreadyInitialized = true;
}
}
/**
* Registers implementing class of the Transform algorithm with algorithmURI
*
* @param algorithmURI algorithmURI URI representation of
* <code>Transform algorithm</code> will be specified as parameter of
* {@link #getInstance(Document, String)}, when generate. </br>
* @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, String implementingClass)
throws AlgorithmAlreadyRegisteredException {
// are we already registered?
Class registeredClass = getImplementingClass(algorithmURI);
if ((registeredClass != null) ) {
Object exArgs[] = { algorithmURI, registeredClass };
throw new AlgorithmAlreadyRegisteredException(
"algorithm.alreadyRegistered", exArgs);
}
try {
transformClassHash.put
(algorithmURI, ClassLoaderUtils.loadClass(implementingClass, Transform.class));
} catch (ClassNotFoundException e) {
throw new RuntimeException(e);
}
}
/**
* 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 {
XMLSignatureInput result = null;
try {
result = transformSpi.enginePerformTransform(input, 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;
}
/**
* 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;
}
/**
* Method getImplementingClass
*
* @param URI
* @return The name of the class implementing the URI.
*/
private static Class getImplementingClass(String URI) {
return (Class) transformClassHash.get(URI);
}
private static TransformSpi getTransformSpi(String URI)
throws InvalidTransformException {
try {
Object value = transformSpiHash.get(URI);
if (value != null) {
return (TransformSpi) value;
}
Class cl = (Class) transformClassHash.get(URI);
if (cl != null) {
TransformSpi tr = (TransformSpi) cl.newInstance();
transformSpiHash.put(URI, tr);
return tr;
}
} catch (InstantiationException ex) {
Object exArgs[] = { URI };
throw new InvalidTransformException(
"signature.Transform.UnknownTransform", exArgs, ex);
} catch (IllegalAccessException ex) {
Object exArgs[] = { URI };
throw new InvalidTransformException(
"signature.Transform.UnknownTransform", exArgs, ex);
}
return null;
}
/** @inheritDoc */
public String getBaseLocalName() {
return Constants._TAG_TRANSFORM;
}
}