/* * @(#)ReferralException.java 1.11 04/07/16 * * Copyright 2004 Sun Microsystems, Inc. All rights reserved. * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms. */ package javax.naming; import java.util.Hashtable; /** * This abstract class is used to represent a referral exception, * which is generated in response to a referral * such as that returned by LDAP v3 servers. *

* A service provider provides * a subclass of ReferralException by providing implementations * for getReferralInfo() and getReferralContext() (and appropriate * constructors and/or corresponding "set" methods). *

* The following code sample shows how ReferralException can be used. * 

 *	while (true) {
 *	    try {
 *		bindings = ctx.listBindings(name);
 *		while (bindings.hasMore()) {
 *		    b = bindings.next();
 *		    ...
 *		}
 *		break;
 *	    } catch (ReferralException e) {
 *		ctx = e.getReferralContext();
 *	    }
 *	}
 *

*

* ReferralException is an abstract class. Concrete implementations * determine its synchronization and serialization properties. *

* An environment parameter passed to the getReferralContext() * method is owned by the caller. * The service provider will not modify the object or keep a reference to it, * but may keep a reference to a clone of it. * * @author Rosanna Lee * @author Scott Seligman * @version 1.11 04/07/16 * * @since 1.3 * */ public abstract class ReferralException extends NamingException { /** * Constructs a new instance of ReferralException using the * explanation supplied. All other fields are set to null. * * @param explanation Additional detail about this exception. Can be null. * @see java.lang.Throwable#getMessage */ protected ReferralException(String explanation) { super(explanation); } /** * Constructs a new instance of ReferralException. * All fields are set to null. */ protected ReferralException() { super(); } /** * Retrieves information (such as URLs) related to this referral. * The program may examine or display this information * to the user to determine whether to continue with the referral, * or to determine additional information needs to be supplied in order * to continue with the referral. * * @return Non-null referral information related to this referral. */ public abstract Object getReferralInfo(); /** * Retrieves the context at which to continue the method. * Regardless of whether a referral is encountered directly during a * context operation, or indirectly, for example, during a search * enumeration, the referral exception should provide a context * at which to continue the operation. The referral context is * created using the environment properties of the context * that threw the ReferralException. * *

* To continue the operation, the client program should re-invoke * the method using the same arguments as the original invocation. * * @return The non-null context at which to continue the method. * @exception NamingException If a naming exception was encountered. * Call either retryReferral() or skipReferral() * to continue processing referrals. */ public abstract Context getReferralContext() throws NamingException; /** * Retrieves the context at which to continue the method using * environment properties. * Regardless of whether a referral is encountered directly during a * context operation, or indirectly, for example, during a search * enumeration, the referral exception should provide a context * at which to continue the operation. *

* The referral context is created using env as its environment * properties. * This method should be used instead of the no-arg overloaded form * when the caller needs to use different environment properties for * the referral context. It might need to do this, for example, when * it needs to supply different authentication information to the referred * server in order to create the referral context. *

* To continue the operation, the client program should re-invoke * the method using the same arguments as the original invocation. * * @param env The possibly null environment to use when retrieving the * referral context. If null, no environment properties will be used. * * @return The non-null context at which to continue the method. * @exception NamingException If a naming exception was encountered. * Call either retryReferral() or skipReferral() * to continue processing referrals. */ public abstract Context getReferralContext(Hashtable env) throws NamingException; /** * Discards the referral about to be processed. * A call to this method should be followed by a call to * getReferralContext to allow the processing of * other referrals to continue. * The following code fragment shows a typical usage pattern. * 

     *	} catch (ReferralException e) {
     *	    if (!shallIFollow(e.getReferralInfo())) {
     *		if (!e.skipReferral()) {
     *		    return;
     *		}
     *	    }
     *	    ctx = e.getReferralContext();
     *	}
     *
* * @return true If more referral processing is pending; false otherwise. */ public abstract boolean skipReferral(); /** * Retries the referral currently being processed. * A call to this method should be followed by a call to * getReferralContext to allow the current * referral to be retried. * The following code fragment shows a typical usage pattern. * 

     *	} catch (ReferralException e) {
     *	    while (true) {
     *		try {
     *		    ctx = e.getReferralContext(env);
     *		    break;
     *		} catch (NamingException ne) {
     *		    if (! shallIRetry()) {
     *			return;
     *		    }
     *		    // modify environment properties (env), if necessary
     *		    e.retryReferral();
     *		}
     *	    }
     *	}
     *
* */ public abstract void retryReferral(); /** * Use serialVersionUID from JNDI 1.1.1 for interoperability */ private static final long serialVersionUID = -2881363844695698876L; }