/*
 * @(#)ExtendedRequest.java	1.7 01/12/03
 *
 * Copyright 2002 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package javax.naming.ldap;

import javax.naming.NamingException;

/**
  * This interface represents an LDAPv3 extended operation request as defined in
  * <A HREF="ftp://ftp.isi.edu/in-notes/rfc2251.txt">RFC 2251</A>.
  * <pre>
  *     ExtendedRequest ::= [APPLICATION 23] SEQUENCE {
  *              requestName      [0] LDAPOID,
  *              requestValue     [1] OCTET STRING OPTIONAL }
  * </pre>
  * It comprises an object identifier string and an optional ASN.1 BER
  * encoded value.
  *<p>
  * The methods in this class are used by the service provider to construct
  * the bits to send to the LDAP server. Applications typically only deal with
  * the classes that implement this interface, supplying them with
  * any information required for a particular extended operation request.
  * It would then pass such a class as an argument to the
  * <tt>LdapContext.extendedOperation()</tt> method for performing the
  * LDAPv3 extended operation.
  *<p>
  * For example, suppose the LDAP server supported a 'get time' extended operation.
  * It would supply GetTimeRequest and GetTimeResponse classes:
  *<blockquote><pre>
  * public class GetTimeRequest implements ExtendedRequest {
  *     public GetTimeRequest() {... };
  *     public ExtendedResponse createExtendedResponse(String id, 
  * 	    byte[] berValue, int offset, int length) 
  *	    throws NamingException {
  *         return new GetTimeResponse(id, berValue, offset, length);
  *     }
  *     ...
  * }
  * public class GetTimeResponse implements ExtendedResponse {
  *     long time;
  *     public GetTimeResponse(String id, byte[] berValue, int offset, 
  * 	    int length) throws NamingException {
  *         time =	... // decode berValue to get time
  *     }
  *     public java.util.Date getDate() { return new java.util.Date(time) };
  *     public long getTime() { return time };
  *     ...
  * }
  *</pre></blockquote>
  * A program would use then these classes as follows:
  *<blockquote><pre>
  * GetTimeResponse resp =
  * 	(GetTimeResponse) ectx.extendedOperation(new GetTimeRequest());
  * long time = resp.getTime();
  *</pre></blockquote>
  * 
  * @author Rosanna Lee
  * @author Scott Seligman
  * @author Vincent Ryan
  * @version 1.7 01/12/03
  *
  * @see ExtendedResponse
  * @see LdapContext#extendedOperation
  * @since 1.3
  */
public interface ExtendedRequest extends java.io.Serializable {

    /**
      * Retrieves the object identifier of the request.
      *
      * @return The non-null object identifier string representing the LDAP
      *		<tt>ExtendedRequest.requestName</tt> component.
      */
    public String getID();

    /**
      * Retrieves the ASN.1 BER encoded value of the LDAP extended operation
      * request. Null is returned if the value is absent.
      *
      * The result is the raw BER bytes including the tag and length of
      * the request value. It does not include the request OID.
      * This method is called by the service provider to get the bits to
      * put into the extended operation to be sent to the LDAP server.
      *
      * @return A possibly null byte array representing the ASN.1 BER encoded
      *         contents of the LDAP <tt>ExtendedRequest.requestValue</tt>
      *         component.
      * @exception IllegalStateException If the encoded value cannot be retrieved
      * because the request contains insufficient or invalid data/state.
      */
    public byte[] getEncodedValue();

    /**
      * Creates the response object that corresponds to this request.
      *<p>
      * After the service provider has sent the extended operation request
      * to the LDAP server, it will receive a response from the server.
      * If the operation failed, the provider will throw a NamingException.
      * If the operation succeeded, the provider will invoke this method
      * using the data that it got back in the response.
      * It is the job of this method to return a class that implements
      * the ExtendedResponse interface that is appropriate for the
      * extended operation request.
      *<p>
      * For example, a Start TLS extended request class would need to know
      * how to process a Start TLS extended response. It does this by creating
      * a class that implements ExtendedResponse.
      *
      * @param id	The possibly null object identifier of the response
      *			control.
      * @param berValue	The possibly null ASN.1 BER encoded value of the
      *			response control. 
      * This is the raw BER bytes including the tag and length of
      * the response value. It does not include the response OID.
      * @param offset   The starting position in berValue of the bytes to use.
      * @param length   The number of bytes in berValue to use.
      *
      * @return A non-null object.
      * @exception NamingException if cannot create extended response 
      *     due to an error.
      * @see ExtendedResponse
      */
    public ExtendedResponse createExtendedResponse(String id,
		byte[] berValue, int offset, int length) throws NamingException;

    // static final long serialVersionUID = -7560110759229059814L;
}
