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/*
 * $Id: Transform.java,v 1.5 2005/05/10 16:03:48 mullan Exp $
 */
package javax.xml.crypto.dsig;

import java.io.OutputStream;
import java.security.spec.AlgorithmParameterSpec;
import javax.xml.crypto.AlgorithmMethod;
import javax.xml.crypto.Data;
import javax.xml.crypto.OctetStreamData;
import javax.xml.crypto.XMLCryptoContext;
import javax.xml.crypto.XMLStructure;
import javax.xml.crypto.dsig.spec.TransformParameterSpec;

A representation of the XML Transform element as defined in the W3C Recommendation for XML-Signature Syntax and Processing. The XML Schema Definition is defined as:
<element name="Transform" type="ds:TransformType"/>
  <complexType name="TransformType" mixed="true">
    <choice minOccurs="0" maxOccurs="unbounded">
      <any namespace="##other" processContents="lax"/>
      <!-- (1,1) elements from (0,unbounded) namespaces -->
      <element name="XPath" type="string"/>
    </choice>
    <attribute name="Algorithm" type="anyURI" use="required"/>
  </complexType>
A Transform instance may be created by invoking the newTransform method of the XMLSignatureFactory class.
Author:Sean Mullan, JSR 105 Expert Group
See Also:
Since:1.6
/** * A representation of the XML <code>Transform</code> element as * defined in the <a href="http://www.w3.org/TR/xmldsig-core/"> * W3C Recommendation for XML-Signature Syntax and Processing</a>. * The XML Schema Definition is defined as: * * <pre> * &lt;element name="Transform" type="ds:TransformType"/&gt; * &lt;complexType name="TransformType" mixed="true"&gt; * &lt;choice minOccurs="0" maxOccurs="unbounded"&gt; * &lt;any namespace="##other" processContents="lax"/&gt; * &lt;!-- (1,1) elements from (0,unbounded) namespaces --&gt; * &lt;element name="XPath" type="string"/&gt; * &lt;/choice&gt; * &lt;attribute name="Algorithm" type="anyURI" use="required"/&gt; * &lt;/complexType&gt; * </pre> * * A <code>Transform</code> instance may be created by invoking the * {@link XMLSignatureFactory#newTransform newTransform} method * of the {@link XMLSignatureFactory} class. * * @author Sean Mullan * @author JSR 105 Expert Group * @since 1.6 * @see XMLSignatureFactory#newTransform(String, TransformParameterSpec) */
public interface Transform extends XMLStructure, AlgorithmMethod {
The Base64 transform algorithm URI.
/** * The <a href="http://www.w3.org/2000/09/xmldsig#base64">Base64</a> * transform algorithm URI. */
final static String BASE64 = "http://www.w3.org/2000/09/xmldsig#base64";
The Enveloped Signature transform algorithm URI.
/** * The <a href="http://www.w3.org/2000/09/xmldsig#enveloped-signature"> * Enveloped Signature</a> transform algorithm URI. */
final static String ENVELOPED = "http://www.w3.org/2000/09/xmldsig#enveloped-signature";
The XPath transform algorithm URI.
/** * The <a href="http://www.w3.org/TR/1999/REC-xpath-19991116">XPath</a> * transform algorithm URI. */
final static String XPATH = "http://www.w3.org/TR/1999/REC-xpath-19991116";
The XPath Filter 2 transform algorithm URI.
/** * The <a href="http://www.w3.org/2002/06/xmldsig-filter2"> * XPath Filter 2</a> transform algorithm URI. */
final static String XPATH2 = "http://www.w3.org/2002/06/xmldsig-filter2";
The XSLT transform algorithm URI.
/** * The <a href="http://www.w3.org/TR/1999/REC-xslt-19991116">XSLT</a> * transform algorithm URI. */
final static String XSLT = "http://www.w3.org/TR/1999/REC-xslt-19991116";
Returns the algorithm-specific input parameters associated with this Transform.

The returned parameters can be typecast to a TransformParameterSpec object.

Returns:the algorithm-specific input parameters (may be null if not specified)
/** * Returns the algorithm-specific input parameters associated with this * <code>Transform</code>. * <p> * The returned parameters can be typecast to a * {@link TransformParameterSpec} object. * * @return the algorithm-specific input parameters (may be <code>null</code> * if not specified) */
AlgorithmParameterSpec getParameterSpec();
Transforms the specified data using the underlying transform algorithm.
Params:
  • data – the data to be transformed
  • context – the XMLCryptoContext containing additional context (may be null if not applicable)
Throws:
Returns:the transformed data
/** * Transforms the specified data using the underlying transform algorithm. * * @param data the data to be transformed * @param context the <code>XMLCryptoContext</code> containing * additional context (may be <code>null</code> if not applicable) * @return the transformed data * @throws NullPointerException if <code>data</code> is <code>null</code> * @throws TransformException if an error occurs while executing the * transform */
public abstract Data transform(Data data, XMLCryptoContext context) throws TransformException;
Transforms the specified data using the underlying transform algorithm. If the output of this transform is an OctetStreamData, then this method returns null and the bytes are written to the specified OutputStream. Otherwise, the OutputStream is ignored and the method behaves as if transform(Data, XMLCryptoContext) were invoked.
Params:
  • data – the data to be transformed
  • context – the XMLCryptoContext containing additional context (may be null if not applicable)
  • os – the OutputStream that should be used to write the transformed data to
Throws:
Returns:the transformed data (or null if the data was written to the OutputStream parameter)
/** * Transforms the specified data using the underlying transform algorithm. * If the output of this transform is an <code>OctetStreamData</code>, then * this method returns <code>null</code> and the bytes are written to the * specified <code>OutputStream</code>. Otherwise, the * <code>OutputStream</code> is ignored and the method behaves as if * {@link #transform(Data, XMLCryptoContext)} were invoked. * * @param data the data to be transformed * @param context the <code>XMLCryptoContext</code> containing * additional context (may be <code>null</code> if not applicable) * @param os the <code>OutputStream</code> that should be used to write * the transformed data to * @return the transformed data (or <code>null</code> if the data was * written to the <code>OutputStream</code> parameter) * @throws NullPointerException if <code>data</code> or <code>os</code> * is <code>null</code> * @throws TransformException if an error occurs while executing the * transform */
public abstract Data transform (Data data, XMLCryptoContext context, OutputStream os) throws TransformException; }