Package eu.tneitzel.rmg.networking

Class RMIRegistryEndpoint

  • public class RMIRegistryEndpoint
extends RMIEndpoint
    The RMIRegistryEndpoint represents an RMI Registry endpoint on the remote server. The class can be used to perform some more high level RMI registry access like list and lookup operations. However, as it extends RMIEndpoint, all low level RMI functionality is also available.
    Author:
    Tobias Neitzel (@qtc_de)

    • Constructor Detail

      • RMIRegistryEndpoint

        public RMIRegistryEndpoint​(String host,
                           int port)
        The main purpose of this constructor function is to setup the different socket factories. During the initial connect to the registry, a socket factory can be specified manually and will be used. This is done by the RMIEndpoint class already. However, for the communication to looked up remote objects, the socket factory that was configured on the server side will be used. For most cases this will be either RMISocketFactory or SslRMIClientSocketFactory. To implement stuff like automatic redirection, we need to overwrite the default implementations of these classes. This is done by this constructor.
        Parameters:
        host - RMI registry host
        port - RMI registry port

      • RMIRegistryEndpoint

        public RMIRegistryEndpoint​(RMIEndpoint rmi)
        Alternative constructor that creates the RMIRegistryEndpoint from an already existing RMIEndpoint.
        Parameters:
        rmi - RMIEndpoint

    • Method Detail

      • getBoundNames

        public String[] getBoundNames()
                       throws NoSuchObjectException
        If a bound name was specified on the command line, return this bound name immediately. Otherwise, obtain a list of bound names from the RMI registry. This is basically a wrapper around the list function of the RMI registry, but has error handling implemented.
        Returns:
        String array of available bound names.
        Throws:
        NoSuchObjectException - if the remote endpoint is not an RMI registry

      • lookup

        public Remote[] lookup​(String[] boundNames)
                throws UnmarshalException
        Performs the RMI registries lookup operation to obtain a remote reference for the specified bound names. The main benefit of using this method is, that it performs exception handling.
        Parameters:
        boundNames - list of bound names to determine the classes from
        Returns:
        List of remote objects looked up from the remote registry
        Throws:
        UnmarshalException - if unmarshaling the return value fails

      • lookup

        public Remote lookup​(String boundName)
              throws UnmarshalException
        Just a wrapper around the lookup method of the RMI registry. Performs exception handling and caches remote objects that have already been looked up.
        Parameters:
        boundName - name to lookup within the registry
        Returns:
        Remote representing the requested remote object
        Throws:
        UnmarshalException - if unmarshalling the return value fails

      • lookupWithRetries

        public Remote lookupWithRetries​(String boundName,
                                int maxRetries)
        It was observed that using --serial-version-uid option can cause an invalid transport return code exception during lookup. This seems to be some kind of race condition and cannot be reproduced reliably. We currently believe that RMI / Java does not clear the ObjectInput stream when reading an unknown class from it. The remaining bytes are left within the stream. Since RMI uses connection pooling, the next operation encounters the invalid bytes and fails. If this is the case, we just retry a few times.
        Parameters:
        boundName - the bound name to lookup
        maxRetries - the maximum amount of retries to perform
        Returns:
        Remote object if lookup was successful. null otherwise.

      • lookupWrapper

        public RemoteObjectWrapper lookupWrapper​(String boundName)
        Same as the lookup action, but returns a RemoteObjectWrapper.
        Parameters:
        boundName - name to lookup within the registry
        Returns:
        RemoteObjectWrapper for the remote object

      • lookupWrappers

        public RemoteObjectWrapper[] lookupWrappers​(String[] boundNames)
        Same as the lookup action, but returns an array of RemoteObjectWrapper.
        Parameters:
        boundNames - names to lookup within the registry
        Returns:
        RemoteObjectWrapper for the remote object

      • getFromCache

        public Remote getFromCache​(String boundName)
        Return the Remote for the specified bound name from cache or null if it is not available.
        Parameters:
        boundName - name to lookup within the cache
        Returns:
        Remote representing the requested remote object