Class ReferralException

public abstract class ReferralException
extends NamingException

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.

Constructors

ReferralException

protected ReferralException(String explanation)

Constructs a new instance of ReferralException using the explanation supplied. All other fields are set to null.

Parameters:

explanation - Additional detail about this exception. Can be null.

See Also:

Throwable.getMessage()

ReferralException

protected ReferralException()

Constructs a new instance of ReferralException. All fields are set to null.

Methods

getReferralInfo

public abstract Object getReferralInfo()

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.

Returns:

Non-null referral information related to this referral.

getReferralContext

public abstract Context getReferralContext()
                                    throws NamingException

Returns:

The non-null context at which to continue the method.

Throws:

NamingException - If a naming exception was encountered. Call either retryReferral() or skipReferral() to continue processing referrals.

getReferralContext

public abstract Context getReferralContext(Hashtable<?,?> env)
                                    throws NamingException

Parameters:

env - The possibly null environment to use when retrieving the referral context. If null, no environment properties will be used.

Returns:

The non-null context at which to continue the method.

Throws:

NamingException - If a naming exception was encountered. Call either retryReferral() or skipReferral() to continue processing referrals.

skipReferral

public abstract boolean skipReferral()

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();
}

Returns:

true If more referral processing is pending; false otherwise.

retryReferral

public abstract void retryReferral()

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();
        }
    }
}