Module java.naming
Package javax.naming

Class ReferralException

  • All Implemented Interfaces:
    Serializable
    Direct Known Subclasses:
    LdapReferralException
    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.

    Since:
    1.3
    See Also:
    Serialized Form

    • Constructor Detail

      • 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.

    • Method Detail

      • 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
        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.

        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
        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.

        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();
          }
      }
  }