/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
*/
/*
* $Id: RetrievalMethod.java,v 1.8 2005/05/10 16:35:35 mullan Exp $
*/
package javax.xml.crypto.dsig.keyinfo;
import javax.xml.crypto.Data;
import javax.xml.crypto.URIReference;
import javax.xml.crypto.URIReferenceException;
import javax.xml.crypto.XMLCryptoContext;
import javax.xml.crypto.XMLStructure;
import javax.xml.crypto.dsig.Transform;
import java.util.List;
/**
* A representation of the XML <code>RetrievalMethod</code> element as
* defined in the <a href="http://www.w3.org/TR/xmldsig-core/">
* W3C Recommendation for XML-Signature Syntax and Processing</a>.
* A <code>RetrievalMethod</code> object is used to convey a reference to
* <code>KeyInfo</code> information that is stored at another location.
* The XML schema definition is defined as:
*
* <pre>
* <element name="RetrievalMethod" type="ds:RetrievalMethodType"/>
* <complexType name="RetrievalMethodType">
* <sequence>
* <element name="Transforms" type="ds:TransformsType" minOccurs="0"/>
* </sequence>
* <attribute name="URI" type="anyURI"/>
* <attribute name="Type" type="anyURI" use="optional"/>
* </complexType>
* </pre>
*
* A <code>RetrievalMethod</code> instance may be created by invoking one of the
* {@link KeyInfoFactory#newRetrievalMethod newRetrievalMethod} methods
* of the {@link KeyInfoFactory} class, and passing it the URI
* identifying the location of the KeyInfo, an optional type URI identifying
* the type of KeyInfo, and an optional list of {@link Transform}s; for example:
* <pre>
* KeyInfoFactory factory = KeyInfoFactory.getInstance("DOM");
* RetrievalMethod rm = factory.newRetrievalMethod
* ("#KeyValue-1", KeyValue.DSA_TYPE, Collections.singletonList(Transform.BASE64));
* </pre>
*
* @author Sean Mullan
* @author JSR 105 Expert Group
* @since 1.6
* @see KeyInfoFactory#newRetrievalMethod(String)
* @see KeyInfoFactory#newRetrievalMethod(String, String, List)
*/
public interface RetrievalMethod extends URIReference, XMLStructure {
/**
* Returns an {@link java.util.Collections#unmodifiableList unmodifiable
* list} of {@link Transform}s of this <code>RetrievalMethod</code>.
*
* @return an unmodifiable list of <code>Transform</code> objects (may be
* empty but never <code>null</code>).
*/
List getTransforms();
/**
* Returns the URI of the referenced <code>KeyInfo</code> information.
*
* @return the URI of the referenced <code>KeyInfo</code> information in
* RFC 2396 format (never <code>null</code>)
*/
String getURI();
/**
* Dereferences the <code>KeyInfo</code> information referenced by this
* <code>RetrievalMethod</code> and applies the specified
* <code>Transform</code>s.
*
* @param context an <code>XMLCryptoContext</code> that may contain
* additional useful information for dereferencing the URI. The
* context's <code>baseURI</code> and <code>dereferencer</code>
* parameters (if specified) are used to resolve and dereference this
* <code>RetrievalMethod</code>
* @return a <code>Data</code> object representing the raw contents of the
* <code>KeyInfo</code> information referenced by this
* <code>RetrievalMethod</code>. It is the caller's responsibility to
* convert the returned data to an appropriate
* <code>KeyInfo</code> object.
* @throws NullPointerException if <code>context</code> is <code>null</code>
* @throws URIReferenceException if there is an error while dereferencing
*/
Data dereference(XMLCryptoContext context) throws URIReferenceException;
}