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Java example source code file (Delegate.java)

This example Java source code file (Delegate.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

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Java - Java tags/keywords

applicationexception, class, context, contextlist, corba, delegate, exceptionlist, inputstream, namedvalue, nvlist, outputstream, remarshalexception, request, servantobject, string

The Delegate.java Java example source code

/*
 * Copyright (c) 1997, 2002, 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 org.omg.CORBA.portable;

import org.omg.CORBA.Request;
import org.omg.CORBA.NamedValue;
import org.omg.CORBA.NVList;
import org.omg.CORBA.Context;
import org.omg.CORBA.ContextList;
import org.omg.CORBA.ExceptionList;
import org.omg.CORBA.TypeCode;
import org.omg.CORBA.SystemException;

/**
 * Specifies a portable API for ORB-vendor-specific
 * implementation of the org.omg.CORBA.Object methods.
 *
 * Each stub (proxy) contains a delegate
 * object, to which all org.omg.CORBA.Object methods are forwarded.
 * This allows a stub generated by one vendor's ORB to work with the delegate
 * from another vendor's ORB.
 *
 * @see org.omg.CORBA.Object
 * @author OMG
 */

public abstract class Delegate {

    /**
     * Return an InterfaceDef for the object reference provided.
     * @param self The object reference whose InterfaceDef needs to be returned
     * @return the InterfaceDef
     */
    public abstract org.omg.CORBA.Object get_interface_def(
        org.omg.CORBA.Object self);

    /**
     * Returns a duplicate of the object reference provided.
     * @param obj The object reference whose duplicate needs to be returned
     * @return the duplicate object reference
     */
    public abstract org.omg.CORBA.Object duplicate(org.omg.CORBA.Object obj);

    /**
     * Releases resources associated with the object reference provided.
     * @param obj The object reference whose resources need to be released
     */
    public abstract void release(org.omg.CORBA.Object obj);

    /**
     * Checks if the object reference is an instance of the given interface.
     * @param obj The object reference to be checked.
     * @param repository_id The repository identifier of the interface
     * to check against.
     * @return true if the object reference supports the interface
     */
    public abstract boolean is_a(org.omg.CORBA.Object obj, String repository_id);

    /**
     * Determines whether the server object for the object reference has been
     * destroyed.
     * @param obj The object reference which delegated to this delegate.
     * @return true if the ORB knows authoritatively that the server object does
     * not exist, false otherwise
     */
    public abstract boolean non_existent(org.omg.CORBA.Object obj);

    /**
     * Determines if the two object references are equivalent.
     * @param obj The object reference which delegated to this delegate.
     * @param other The object reference to check equivalence against.
     * @return true if the objects are CORBA-equivalent.
     */
    public abstract boolean is_equivalent(org.omg.CORBA.Object obj,
                                          org.omg.CORBA.Object other);

    /**
     * Returns an ORB-internal identifier (hashcode) for this object reference.
     * @param obj The object reference which delegated to this delegate.
     * @param max specifies an upper bound on the hash value returned by
     *            the ORB.
     * @return ORB-internal hash identifier for object reference
     */
    public abstract int hash(org.omg.CORBA.Object obj, int max);

    /**
     * Creates a Request instance for use in the Dynamic Invocation Interface.
     * @param obj The object reference which delegated to this delegate.
     * @param operation The name of the operation to be invoked using the
     *                  Request instance.
     * @return the created Request instance
     */
    public abstract Request request(org.omg.CORBA.Object obj, String operation);

    /**
     * Creates a Request instance for use in the Dynamic Invocation Interface.
     *
     * @param obj The object reference which delegated to this delegate.
     * @param ctx                      The context to be used.
     * @param operation                The name of the operation to be
     *                                 invoked.
     * @param arg_list         The arguments to the operation in the
     *                                 form of an NVList.
     * @param result           A container for the result as a NamedValue.
     * @return                 The created Request object.
     *
     */
    public abstract Request create_request(org.omg.CORBA.Object obj,
                                           Context ctx,
                                           String operation,
                                           NVList arg_list,
                                           NamedValue result);

    /**
     * Creates a Request instance for use in the Dynamic Invocation Interface.
     *
     * @param obj The object reference which delegated to this delegate.
     * @param ctx                      The context to be used.
     * @param operation                The name of the operation to be
     *                                 invoked.
     * @param arg_list         The arguments to the operation in the
     *                                 form of an NVList.
     * @param result           A container for the result as a NamedValue.
     * @param exclist          A list of possible exceptions the
     *                                 operation can throw.
     * @param ctxlist          A list of context strings that need
     *                                 to be resolved and sent with the
     *                                 Request.
     * @return                 The created Request object.
     */
    public abstract Request create_request(org.omg.CORBA.Object obj,
                                           Context ctx,
                                           String operation,
                                           NVList arg_list,
                                           NamedValue result,
                                           ExceptionList exclist,
                                           ContextList ctxlist);

    /**
     * Provides a reference to the orb associated with its parameter.
     *
     * @param obj  the object reference which delegated to this delegate.
     * @return the associated orb.
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public org.omg.CORBA.ORB orb(org.omg.CORBA.Object obj) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }

    /**
     * Returns the <code>Policy object of the specified type
     * which applies to this object.
     *
     * @param self The object reference which delegated to this delegate.
     * @param policy_type The type of policy to be obtained.
     * @return A <code>Policy object of the type specified by
     *         the policy_type parameter.
     * @exception org.omg.CORBA.BAD_PARAM raised when the value of policy type
     * is not valid either because the specified type is not supported by this
     * ORB or because a policy object of that type is not associated with this
     * Object.
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public org.omg.CORBA.Policy get_policy(org.omg.CORBA.Object self,
                                           int policy_type) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }


    /**
     * Retrieves the <code>DomainManagers of this object.
     * This allows administration services (and applications) to retrieve the
     * domain managers, and hence the security and other policies applicable
     * to individual objects that are members of the domain.
     *
     * @param self The object reference which delegated to this delegate.
     * @return The list of immediately enclosing domain managers of this object.
     *  At least one domain manager is always returned in the list since by
     * default each object is associated with at least one domain manager at
     * creation.
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public org.omg.CORBA.DomainManager[] get_domain_managers(
                                                             org.omg.CORBA.Object
                                                             self) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }


    /**
     * Associates the policies passed in
     * with a newly created object reference that it returns. Only certain
     * policies that pertain to the invocation of an operation at the client
     * end can be overridden using this operation. Attempts to override any
     * other policy will result in the raising of the CORBA::NO_PERMISSION
     * exception.
     *
     * @param self The object reference which delegated to this delegate.
     * @param policies A sequence of references to Policy objects.
     * @param set_add Indicates whether these policies should be added
     * onto any otheroverrides that already exist (ADD_OVERRIDE) in
     * the object reference, or they should be added to a clean
     * override free object reference (SET_OVERRIDE).
     * @return  A new object reference with the new policies associated with it.
     *
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public org.omg.CORBA.Object set_policy_override(org.omg.CORBA.Object self,
                                                    org.omg.CORBA.Policy[] policies,
                                                    org.omg.CORBA.SetOverrideType set_add) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }


    /**
     * Returns true if this object is implemented by a local servant.
     *
     * @param self The object reference which delegated to this delegate.
     * @return true only if the servant incarnating this object is located in
     * this Java VM. Return false if the servant is not local or the ORB
     * does not support local stubs for this particular servant. The default
     * behavior of is_local() is to return false.
     */
    public boolean is_local(org.omg.CORBA.Object self) {
        return false;
    }

    /**
     * Returns a Java reference to the servant which should be used for this
     * request. servant_preinvoke() is invoked by a local stub.
     * If a ServantObject object is returned, then its servant field
     * has been set to an object of the expected type (Note: the object may
     * or may not be the actual servant instance). The local stub may cast
     * the servant field to the expected type, and then invoke the operation
     * directly. The ServantRequest object is valid for only one invocation,
     * and cannot be used for more than one invocation.
     *
     * @param self The object reference which delegated to this delegate.
     *
     * @param operation a string containing the operation name.
     * The operation name corresponds to the operation name as it would be
     * encoded in a GIOP request.
     *
     * @param expectedType a Class object representing the expected type of the servant.
     * The expected type is the Class object associated with the operations
     * class of the stub's interface (e.g. A stub for an interface Foo,
     * would pass the Class object for the FooOperations interface).
     *
     * @return a ServantObject object.
     * The method may return a null value if it does not wish to support
     * this optimization (e.g. due to security, transactions, etc).
     * The method must return null if the servant is not of the expected type.
     */
    public ServantObject servant_preinvoke(org.omg.CORBA.Object self,
                                           String operation,
                                           Class expectedType) {
        return null;
    }

    /**
     * servant_postinvoke() is invoked by the local stub after the operation
     * has been invoked on the local servant.
     * This method must be called if servant_preinvoke() returned a non-null
     * value, even if an exception was thrown by the servant's method.
     * For this reason, the call to servant_postinvoke() should be placed
     * in a Java finally clause.
     *
     * @param self The object reference which delegated to this delegate.
     *
     * @param servant the instance of the ServantObject returned from
     *  the servant_preinvoke() method.
     */
    public void servant_postinvoke(org.omg.CORBA.Object self,
                                   ServantObject servant) {
    }

    /**
     * request is called by a stub to obtain an OutputStream for
     * marshaling arguments. The stub must supply the operation name,
     * and indicate if a response is expected (i.e is this a oneway
     * call).
     *
     * @param self The object reference which delegated to this delegate.
     * @param operation a string containing the operation name.
     * The operation name corresponds to the operation name as it would be
     * encoded in a GIOP request.
     * @param responseExpected false if the operation is a one way operation,
     * and true otherwise.
     * @return OutputStream the OutputStream into which request arguments
     * can be marshaled.
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public OutputStream request(org.omg.CORBA.Object self,
                                String operation,
                                boolean responseExpected) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }

    /**
     * invoke is called by a stub to invoke an operation. The stub provides an
     * OutputStream that was previously returned by a request()
     * call. invoke returns an InputStream which contains the
     * marshaled reply. If an exception occurs, invoke may throw an
     * ApplicationException object which contains an InputStream from
     * which the user exception state may be unmarshaled.
     *
     * @param self The object reference which delegated to this delegate.
     * @param output the OutputStream which contains marshaled arguments
     * @return input the InputStream from which reply parameters can be
     * unmarshaled.
     * @throws ApplicationException thrown when implementation throws
     * (upon invocation) an exception defined as part of its remote method
     * definition.
     * @throws RemarshalException thrown when remarshalling fails.
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public InputStream invoke(org.omg.CORBA.Object self,
                              OutputStream output)
        throws ApplicationException, RemarshalException {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }

    /**
     * releaseReply may optionally be called by a stub to release a
     * reply stream back to the ORB when the unmarshaling has
     * completed. The stub passes the InputStream returned by
     * invoke() or ApplicationException.getInputStream(). A null
     * value may also be passed to releaseReply, in which case the
     * method is a noop.
     *
     * @param self The object reference which delegated to this delegate.
     * @param input the InputStream returned from invoke().
     * @see <a href="package-summary.html#unimpl">portable
     * package comments for unimplemented features</a>
     */
    public void releaseReply(org.omg.CORBA.Object self,
                             InputStream input) {
        throw new org.omg.CORBA.NO_IMPLEMENT();
    }

    /**
     * Provides the implementation to override the toString() method
     * of the delegating CORBA object.
     *
     * @param self the object reference that delegated to this delegate
     * @return a <code>String object that represents the object
     *         reference that delegated to this <code>Delegate
     *         object
     */

    public String toString(org.omg.CORBA.Object self) {
        return self.getClass().getName() + ":" + this.toString();
    }

    /**
     * Provides the implementation to override the hashCode() method
     * of the delegating CORBA object.
     *
     * @param self the object reference that delegated to this delegate
     * @return an <code>int that represents the hashcode for the
     *         object reference that delegated to this <code>Delegate
     *         object
     */
    public int hashCode(org.omg.CORBA.Object self) {
        return System.identityHashCode(self);
    }

    /**
     * Provides the implementation to override the equals(java.lang.Object obj)
     * method of the delegating CORBA object.
     *
     * @param self the object reference that delegated to this delegate
     * @param obj the <code>Object with which to compare
     * @return <code>true if obj equals self;
     *         <code>false otherwise
     */
    public boolean equals(org.omg.CORBA.Object self, java.lang.Object obj) {
        return (self == obj);
    }
}

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