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package java.rmi.server;

import java.rmi.*;

RemoteRef represents the handle for a remote object. A
RemoteStub uses a remote reference to carry out a
remote method invocation to a remote object.
Author:
 Ann Wollrath
See Also:
RemoteStub
Since:
  JDK1.1/**
 * <code>RemoteRef</code> represents the handle for a remote object. A
 * <code>RemoteStub</code> uses a remote reference to carry out a
 * remote method invocation to a remote object.
 *
 * @author  Ann Wollrath
 * @since   JDK1.1
 * @see     java.rmi.server.RemoteStub
 */
public interface RemoteRef extends java.io.Externalizable {

    
indicate compatibility with JDK 1.1.x version of class. /** indicate compatibility with JDK 1.1.x version of class. */
    static final long serialVersionUID = 3632638527362204081L;

    
Initialize the server package prefix: assumes that the
implementation of server ref classes (e.g., UnicastRef,
UnicastServerRef) are located in the package defined by the
prefix.
/**
     * Initialize the server package prefix: assumes that the
     * implementation of server ref classes (e.g., UnicastRef,
     * UnicastServerRef) are located in the package defined by the
     * prefix.
     */
    final static String packagePrefix = "sun.rmi.server";

    
Invoke a method. This form of delegating method invocation
to the reference allows the reference to take care of
setting up the connection to the remote host, marshaling
some representation for the method and parameters, then
communicating the method invocation to the remote host.
This method either returns the result of a method invocation
on the remote object which resides on the remote host or
throws a RemoteException if the call failed or an
application-level exception if the remote invocation throws
an exception.
Params:
obj – the object that contains the RemoteRef (e.g., the
           RemoteStub for the object.
method – the method to be invoked
params – the parameter list
opnum –  a hash that may be used to represent the method
Throws:
Exception – if any exception occurs during remote method
invocation
Returns:
result of remote method invocation
Since:
1.2/**
     * Invoke a method. This form of delegating method invocation
     * to the reference allows the reference to take care of
     * setting up the connection to the remote host, marshaling
     * some representation for the method and parameters, then
     * communicating the method invocation to the remote host.
     * This method either returns the result of a method invocation
     * on the remote object which resides on the remote host or
     * throws a RemoteException if the call failed or an
     * application-level exception if the remote invocation throws
     * an exception.
     *
     * @param obj the object that contains the RemoteRef (e.g., the
     *            RemoteStub for the object.
     * @param method the method to be invoked
     * @param params the parameter list
     * @param opnum  a hash that may be used to represent the method
     * @return result of remote method invocation
     * @exception Exception if any exception occurs during remote method
     * invocation
     * @since 1.2
     */
    Object invoke(Remote obj,
                  java.lang.reflect.Method method,
                  Object[] params,
                  long opnum)
        throws Exception;

    
Creates an appropriate call object for a new remote method
invocation on this object.  Passing operation array and index,
allows the stubs generator to assign the operation indexes and
interpret them. The remote reference may need the operation to
encode in the call.
Params:
obj – remote stub through which to make call
op – array of stub operations
opnum – operation number
hash – stub/skeleton interface hash
Throws:
RemoteException – if failed to initiate new remote call
See Also:
invoke(Remote, Method, Object[], long)
Since:
JDK1.1
Deprecated:
1.2 style stubs no longer use this method. Instead of
using a sequence of method calls on the stub's the remote reference
(newCall, invoke, and done), a
stub uses a single method, invoke(Remote, Method, Object[],
int), on the remote reference to carry out parameter
marshalling, remote method executing and unmarshalling of the return
value.
Returns:
call object representing remote call/**
     * Creates an appropriate call object for a new remote method
     * invocation on this object.  Passing operation array and index,
     * allows the stubs generator to assign the operation indexes and
     * interpret them. The remote reference may need the operation to
     * encode in the call.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls on the stub's the remote reference
     * (<code>newCall</code>, <code>invoke</code>, and <code>done</code>), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param obj remote stub through which to make call
     * @param op array of stub operations
     * @param opnum operation number
     * @param hash stub/skeleton interface hash
     * @return call object representing remote call
     * @throws RemoteException if failed to initiate new remote call
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    RemoteCall newCall(RemoteObject obj, Operation[] op, int opnum, long hash)
        throws RemoteException;

    
Executes the remote call.
Invoke will raise any "user" exceptions which
should pass through and not be caught by the stub.  If any
exception is raised during the remote invocation, invoke should
take care of cleaning up the connection before raising the
"user" or remote exception.
Params:
call – object representing remote call
Throws:
Exception – if any exception occurs during remote method
See Also:
invoke(Remote, Method, Object[], long)
Since:
JDK1.1
Deprecated:
1.2 style stubs no longer use this method. Instead of
using a sequence of method calls to the remote reference
(newCall, invoke, and done), a
stub uses a single method, invoke(Remote, Method, Object[],
int), on the remote reference to carry out parameter
marshalling, remote method executing and unmarshalling of the return
value./**
     * Executes the remote call.
     *
     * Invoke will raise any "user" exceptions which
     * should pass through and not be caught by the stub.  If any
     * exception is raised during the remote invocation, invoke should
     * take care of cleaning up the connection before raising the
     * "user" or remote exception.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls to the remote reference
     * (<code>newCall</code>, <code>invoke</code>, and <code>done</code>), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param call object representing remote call
     * @throws Exception if any exception occurs during remote method
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    void invoke(RemoteCall call) throws Exception;

    
Allows the remote reference to clean up (or reuse) the connection.
Done should only be called if the invoke returns successfully
(non-exceptionally) to the stub.
Params:
call – object representing remote call
Throws:
RemoteException – if remote error occurs during call cleanup
See Also:
invoke(Remote, Method, Object[], long)
Since:
JDK1.1
Deprecated:
1.2 style stubs no longer use this method. Instead of
using a sequence of method calls to the remote reference
(newCall, invoke, and done), a
stub uses a single method, invoke(Remote, Method, Object[],
int), on the remote reference to carry out parameter
marshalling, remote method executing and unmarshalling of the return
value./**
     * Allows the remote reference to clean up (or reuse) the connection.
     * Done should only be called if the invoke returns successfully
     * (non-exceptionally) to the stub.
     *
     * @since JDK1.1
     * @deprecated 1.2 style stubs no longer use this method. Instead of
     * using a sequence of method calls to the remote reference
     * (<code>newCall</code>, <code>invoke</code>, and <code>done</code>), a
     * stub uses a single method, <code>invoke(Remote, Method, Object[],
     * int)</code>, on the remote reference to carry out parameter
     * marshalling, remote method executing and unmarshalling of the return
     * value.
     *
     * @param call object representing remote call
     * @throws RemoteException if remote error occurs during call cleanup
     * @see #invoke(Remote,java.lang.reflect.Method,Object[],long)
     */
    @Deprecated
    void done(RemoteCall call) throws RemoteException;

    
Returns the class name of the ref type to be serialized onto
the stream 'out'.
Params:
out – the output stream to which the reference will be serialized
Returns:
the class name (without package qualification) of the reference
type
Since:
JDK1.1/**
     * Returns the class name of the ref type to be serialized onto
     * the stream 'out'.
     * @param out the output stream to which the reference will be serialized
     * @return the class name (without package qualification) of the reference
     * type
     * @since JDK1.1
     */
    String getRefClass(java.io.ObjectOutput out);

    
Returns a hashcode for a remote object.  Two remote object stubs
that refer to the same remote object will have the same hash code
(in order to support remote objects as keys in hash tables).
See Also:
Hashtable
Returns:
remote object hashcode
Since:
JDK1.1/**
     * Returns a hashcode for a remote object.  Two remote object stubs
     * that refer to the same remote object will have the same hash code
     * (in order to support remote objects as keys in hash tables).
     *
     * @return remote object hashcode
     * @see             java.util.Hashtable
     * @since JDK1.1
     */
    int remoteHashCode();

    
Compares two remote objects for equality.
Returns a boolean that indicates whether this remote object is
equivalent to the specified Object. This method is used when a
remote object is stored in a hashtable.
Params:
obj –     the Object to compare with
See Also:
Hashtable
Returns:
 true if these Objects are equal; false otherwise.
Since:
JDK1.1/**
     * Compares two remote objects for equality.
     * Returns a boolean that indicates whether this remote object is
     * equivalent to the specified Object. This method is used when a
     * remote object is stored in a hashtable.
     * @param   obj     the Object to compare with
     * @return  true if these Objects are equal; false otherwise.
     * @see             java.util.Hashtable
     * @since JDK1.1
     */
    boolean remoteEquals(RemoteRef obj);

    
Returns a String that represents the reference of this remote
object.
Returns:
string representing remote object reference
Since:
JDK1.1/**
     * Returns a String that represents the reference of this remote
     * object.
     * @return string representing remote object reference
     * @since JDK1.1
     */
    String remoteToString();

}