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	/*
	* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	*
	* This code is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License version 2 only, as
	* published by the Free Software Foundation. Oracle designates this
	* particular file as subject to the "Classpath" exception as provided
	* by Oracle in the LICENSE file that accompanied this code.
	*
	* This code is distributed in the hope that it will be useful, but WITHOUT
	* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
	* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	* version 2 for more details (a copy is included in the LICENSE file that
	* accompanied this code).
	*
	* You should have received a copy of the GNU General Public License version
	* 2 along with this work; if not, write to the Free Software Foundation,
	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
	*
	* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
	* or visit www.oracle.com if you need additional information or have any
	* questions.
	*/

	package javax.naming;

	import java.util.Hashtable;

	/**
	* This abstract class is used to represent a referral exception,
	* which is generated in response to a <em>referral</em>
	* such as that returned by LDAP v3 servers.
	* <p>
	* A service provider provides
	* a subclass of <tt>ReferralException</tt> by providing implementations
	* for <tt>getReferralInfo()</tt> and <tt>getReferralContext()</tt> (and appropriate
	* constructors and/or corresponding "set" methods).
	* <p>
	* The following code sample shows how <tt>ReferralException</tt> can be used.
	* <blockquote>{@code
	* while (true) {
	* try {
	* bindings = ctx.listBindings(name);
	* while (bindings.hasMore()) {
	* b = bindings.next();
	* ...
	* }
	* break;
	* } catch (ReferralException e) {
	* ctx = e.getReferralContext();
	* }
	* }
	* }</blockquote>
	*<p>
	* <tt>ReferralException</tt> is an abstract class. Concrete implementations
	* determine its synchronization and serialization properties.
	*<p>
	* An environment parameter passed to the <tt>getReferralContext()</tt>
	* 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
	*
	* @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.
	*
	*<p>
	* 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 <tt>retryReferral()</tt> or <tt>skipReferral()</tt>
	* 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.
	*<p>
	* The referral context is created using <tt>env</tt> 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.
	*<p>
	* 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 <tt>retryReferral()</tt> or <tt>skipReferral()</tt>
	* 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
	* <code>getReferralContext</code> to allow the processing of
	* other referrals to continue.
	* The following code fragment shows a typical usage pattern.
	* <blockquote><pre>
	* } catch (ReferralException e) {
	* if (!shallIFollow(e.getReferralInfo())) {
	* if (!e.skipReferral()) {
	* return;
	* }
	* }
	* ctx = e.getReferralContext();
	* }
	* </pre></blockquote>
	*
	* @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
	* <code>getReferralContext</code> to allow the current
	* referral to be retried.
	* The following code fragment shows a typical usage pattern.
	* <blockquote><pre>
	* } 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();
	* }
	* }
	* }
	* </pre></blockquote>
	*
	*/
	public abstract void retryReferral();

	/**
	* Use serialVersionUID from JNDI 1.1.1 for interoperability
	*/
	private static final long serialVersionUID = -2881363844695698876L;
	}

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