Java example source code file (POAManagerImpl.java)

This example Java source code file (POAManagerImpl.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.

Learn more about this Java project at its project page.

Java - Java tags/keywords

calling, corba, creating, exiting, number, pihandler, poafactory, poamanager, poamanager\'s, poamanagerdeactivator, poamanagerimpl, set, state, string, thread, util

The POAManagerImpl.java Java example source code

/*
 * Copyright (c) 1997, 2004, 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 com.sun.corba.se.impl.oa.poa;

import java.util.Iterator;
import java.util.Collections;
import java.util.Set;
import java.util.HashSet;

import org.omg.CORBA.LocalObject;
import org.omg.CORBA.CompletionStatus ;

import org.omg.PortableServer.POAManager;
import org.omg.PortableServer.POAManagerPackage.State;
import org.omg.PortableServer.POA;

import org.omg.PortableInterceptor.DISCARDING ;
import org.omg.PortableInterceptor.ACTIVE ;
import org.omg.PortableInterceptor.HOLDING ;
import org.omg.PortableInterceptor.INACTIVE ;
import org.omg.PortableInterceptor.NON_EXISTENT ;

import com.sun.corba.se.spi.protocol.PIHandler ;

import com.sun.corba.se.impl.logging.POASystemException ;

import com.sun.corba.se.impl.orbutil.ORBUtility ;

/** POAManagerImpl is the implementation of the POAManager interface.
 *  Its public methods are activate(), hold_requests(), discard_requests()
 *  and deactivate().
 */

public class POAManagerImpl extends org.omg.CORBA.LocalObject implements
    POAManager
{
    private final POAFactory factory ;  // factory which contains global state
                                        // for all POAManagers
    private PIHandler pihandler ;       // for adapterManagerStateChanged
    private State state;                // current state of this POAManager
    private Set poas = new HashSet(4) ; // all poas controlled by this POAManager
    private int nInvocations=0;         // Number of invocations in progress
    private int nWaiters=0;             // Number of threads waiting for
                                        // invocations to complete
    private int myId = 0 ;              // This POAManager's ID
    private boolean debug ;
    private boolean explicitStateChange ; // initially false, set true as soon as
                                        // one of activate, hold_request,
                                        // discard_request, or deactivate is called.

    private String stateToString( State state )
    {
        switch (state.value()) {
            case State._HOLDING : return "State[HOLDING]" ;
            case State._ACTIVE : return "State[ACTIVE]" ;
            case State._DISCARDING : return "State[DISCARDING]" ;
            case State._INACTIVE : return "State[INACTIVE]" ;
        }

        return "State[UNKNOWN]" ;
    }

    public String toString()
    {
        return "POAManagerImpl[myId=" + myId +
            " state=" + stateToString(state) +
            " nInvocations=" + nInvocations +
            " nWaiters=" + nWaiters + "]" ;
    }

    POAFactory getFactory()
    {
        return factory ;
    }

    PIHandler getPIHandler()
    {
        return pihandler ;
    }

    private void countedWait()
    {
        try {
            if (debug) {
                ORBUtility.dprint( this, "Calling countedWait on POAManager " +
                    this + " nWaiters=" + nWaiters ) ;
            }

            nWaiters++ ;
            wait();
        } catch ( java.lang.InterruptedException ex ) {
            // NOP
        } finally {
            nWaiters-- ;

            if (debug) {
                ORBUtility.dprint( this, "Exiting countedWait on POAManager " +
                    this + " nWaiters=" + nWaiters ) ;
            }
        }
    }

    private void notifyWaiters()
    {
        if (debug) {
            ORBUtility.dprint( this, "Calling notifyWaiters on POAManager " +
                this + " nWaiters=" + nWaiters ) ;
        }

        if (nWaiters >0)
            notifyAll() ;
    }

    public int getManagerId()
    {
        return myId ;
    }

    POAManagerImpl( POAFactory factory, PIHandler pihandler )
    {
        this.factory = factory ;
        factory.addPoaManager(this);
        this.pihandler = pihandler ;
        myId = factory.newPOAManagerId() ;
        state = State.HOLDING;
        debug = factory.getORB().poaDebugFlag ;
        explicitStateChange = false ;

        if (debug) {
            ORBUtility.dprint( this, "Creating POAManagerImpl " + this ) ;
        }
    }

    synchronized void addPOA(POA poa)
    {
        // XXX This is probably not the correct error
        if (state.value() == State._INACTIVE) {
            POASystemException wrapper = factory.getWrapper();
            throw wrapper.addPoaInactive( CompletionStatus.COMPLETED_NO ) ;
        }

        poas.add(poa);
    }

    synchronized void removePOA(POA poa)
    {
        poas.remove(poa);
        if ( poas.isEmpty() ) {
            factory.removePoaManager(this);
        }
    }

    public short getORTState()
    {
        switch (state.value()) {
            case State._HOLDING    : return HOLDING.value ;
            case State._ACTIVE     : return ACTIVE.value ;
            case State._INACTIVE   : return INACTIVE.value ;
            case State._DISCARDING : return DISCARDING.value ;
            default                : return NON_EXISTENT.value ;
        }
    }

/****************************************************************************
 * The following four public methods are used to change the POAManager's state.
 *
 * A note on the design of synchronization code:
 * There are 4 places where a thread would need to wait for a condition:
 *      - in hold_requests, discard_requests, deactivate, enter
 * There are 5 places where a thread notifies a condition:
 *      - in activate, hold_requests, discard_requests, deactivate, exit
 *
 * Since each notify needs to awaken waiters in several of the 4 places,
 * and since wait() in Java has the nice property of releasing the lock
 * on its monitor before sleeping, it seemed simplest to have just one
 * monitor object: "this". Thus all notifies will awaken all waiters.
 * On waking up, each waiter verifies that the condition it was waiting
 * for is satisfied, otherwise it goes back into a wait().
 *
 ****************************************************************************/

    /**
     * <code>activate
     * <b>Spec: pages 3-14 thru 3-18
     */
    public synchronized void activate()
        throws org.omg.PortableServer.POAManagerPackage.AdapterInactive
    {
        explicitStateChange = true ;

        if (debug) {
            ORBUtility.dprint( this,
                "Calling activate on POAManager " + this ) ;
        }

        try {
            if ( state.value() == State._INACTIVE )
                throw new org.omg.PortableServer.POAManagerPackage.AdapterInactive();

            // set the state to ACTIVE
            state = State.ACTIVE;

            pihandler.adapterManagerStateChanged( myId, getORTState() ) ;

            // Notify any invocations that were waiting because the previous
            // state was HOLDING, as well as notify any threads that were waiting
            // inside hold_requests() or discard_requests().
            notifyWaiters();
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting activate on POAManager " + this ) ;
            }
        }
    }

    /**
     * <code>hold_requests
     * <b>Spec: pages 3-14 thru 3-18
     */
    public synchronized void hold_requests(boolean wait_for_completion)
        throws org.omg.PortableServer.POAManagerPackage.AdapterInactive
    {
        explicitStateChange = true ;

        if (debug) {
            ORBUtility.dprint( this,
                "Calling hold_requests on POAManager " + this ) ;
        }

        try {
            if ( state.value() == State._INACTIVE )
                throw new org.omg.PortableServer.POAManagerPackage.AdapterInactive();
            // set the state to HOLDING
            state  = State.HOLDING;

            pihandler.adapterManagerStateChanged( myId, getORTState() ) ;

            // Notify any threads that were waiting in the wait() inside
            // discard_requests. This will cause discard_requests to return
            // (which is in conformance with the spec).
            notifyWaiters();

            if ( wait_for_completion ) {
                while ( state.value() == State._HOLDING && nInvocations > 0 ) {
                    countedWait() ;
                }
            }
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting hold_requests on POAManager " + this ) ;
            }
        }
    }

    /**
     * <code>discard_requests
     * <b>Spec: pages 3-14 thru 3-18
     */
    public synchronized void discard_requests(boolean wait_for_completion)
        throws org.omg.PortableServer.POAManagerPackage.AdapterInactive
    {
        explicitStateChange = true ;

        if (debug) {
            ORBUtility.dprint( this,
                "Calling hold_requests on POAManager " + this ) ;
        }

        try {
            if ( state.value() == State._INACTIVE )
                throw new org.omg.PortableServer.POAManagerPackage.AdapterInactive();

            // set the state to DISCARDING
            state = State.DISCARDING;

            pihandler.adapterManagerStateChanged( myId, getORTState() ) ;

            // Notify any invocations that were waiting because the previous
            // state was HOLDING. Those invocations will henceforth be rejected with
            // a TRANSIENT exception. Also notify any threads that were waiting
            // inside hold_requests().
            notifyWaiters();

            if ( wait_for_completion ) {
                while ( state.value() == State._DISCARDING && nInvocations > 0 ) {
                    countedWait() ;
                }
            }
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting hold_requests on POAManager " + this ) ;
            }
        }
    }

    /**
     * <code>deactivate
     * <b>Spec: pages 3-14 thru 3-18
     * Note: INACTIVE is a permanent state.
     */

    public void deactivate(boolean etherealize_objects, boolean wait_for_completion)
        throws org.omg.PortableServer.POAManagerPackage.AdapterInactive
    {
        explicitStateChange = true ;

        try {
            synchronized( this ) {
                if (debug) {
                    ORBUtility.dprint( this,
                        "Calling deactivate on POAManager " + this ) ;
                }

                if ( state.value() == State._INACTIVE )
                    throw new org.omg.PortableServer.POAManagerPackage.AdapterInactive();

                state = State.INACTIVE;

                pihandler.adapterManagerStateChanged( myId, getORTState() ) ;

                // Notify any invocations that were waiting because the previous
                // state was HOLDING. Those invocations will then be rejected with
                // an OBJ_ADAPTER exception. Also notify any threads that were waiting
                // inside hold_requests() or discard_requests().
                notifyWaiters();
            }

            POAManagerDeactivator deactivator = new POAManagerDeactivator( this,
                etherealize_objects, debug ) ;

            if (wait_for_completion)
                deactivator.run() ;
            else {
                Thread thr = new Thread(deactivator) ;
                thr.start() ;
            }
        } finally {
            synchronized(this) {
                if (debug) {
                    ORBUtility.dprint( this,
                        "Exiting deactivate on POAManager " + this ) ;
                }
            }
        }
    }

    private class POAManagerDeactivator implements Runnable
    {
        private boolean etherealize_objects ;
        private POAManagerImpl pmi ;
        private boolean debug ;

        POAManagerDeactivator( POAManagerImpl pmi, boolean etherealize_objects,
            boolean debug )
        {
            this.etherealize_objects = etherealize_objects ;
            this.pmi = pmi ;
            this.debug = debug ;
        }

        public void run()
        {
            try {
                synchronized (pmi) {
                    if (debug) {
                        ORBUtility.dprint( this,
                            "Calling run with etherealize_objects=" +
                            etherealize_objects + " pmi=" + pmi ) ;
                    }

                    while ( pmi.nInvocations > 0 ) {
                        countedWait() ;
                    }
                }

                if (etherealize_objects) {
                    Iterator iterator = null ;

                    // Make sure that poas cannot change while we copy it!
                    synchronized (pmi) {
                        if (debug) {
                            ORBUtility.dprint( this,
                                "run: Preparing to etherealize with pmi=" +
                                pmi ) ;
                        }

                        iterator = (new HashSet(pmi.poas)).iterator();
                    }

                    while (iterator.hasNext()) {
                        // Each RETAIN+USE_SERVANT_MGR poa
                        // must call etherealize for all its objects
                        ((POAImpl)iterator.next()).etherealizeAll();
                    }

                    synchronized (pmi) {
                        if (debug) {
                            ORBUtility.dprint( this,
                                "run: removing POAManager and clearing poas " +
                                "with pmi=" + pmi ) ;
                        }

                        factory.removePoaManager(pmi);
                        poas.clear();
                    }
                }
            } finally {
                if (debug) {
                    synchronized (pmi) {
                        ORBUtility.dprint( this, "Exiting run" ) ;
                    }
                }
            }
        }
    }

    /**
     * Added according to the spec CORBA V2.3; this returns the
     * state of the POAManager
     */

    public org.omg.PortableServer.POAManagerPackage.State get_state () {
        return state;
    }

/****************************************************************************
 * The following methods are used on the invocation path.
 ****************************************************************************/

    // called from POA.find_POA before calling
    // AdapterActivator.unknown_adapter.
    synchronized void checkIfActive()
    {
        try {
            if (debug) {
                ORBUtility.dprint( this,
                    "Calling checkIfActive for POAManagerImpl " + this ) ;
            }

            checkState();
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting checkIfActive for POAManagerImpl " + this ) ;
            }
        }
    }

    private void checkState()
    {
        while ( state.value() != State._ACTIVE ) {
            switch ( state.value() ) {
                case State._HOLDING:
                    while ( state.value() == State._HOLDING ) {
                        countedWait() ;
                    }
                    break;

                case State._DISCARDING:
                    throw factory.getWrapper().poaDiscarding() ;

                case State._INACTIVE:
                    throw factory.getWrapper().poaInactive() ;
            }
        }
    }

    synchronized void enter()
    {
        try {
            if (debug) {
                ORBUtility.dprint( this,
                    "Calling enter for POAManagerImpl " + this ) ;
            }

            checkState();
            nInvocations++;
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting enter for POAManagerImpl " + this ) ;
            }
        }
    }

    synchronized void exit()
    {
        try {
            if (debug) {
                ORBUtility.dprint( this,
                    "Calling exit for POAManagerImpl " + this ) ;
            }

            nInvocations--;

            if ( nInvocations == 0 ) {
                // This notifies any threads that were in the
                // wait_for_completion loop in hold/discard/deactivate().
                notifyWaiters();
            }
        } finally {
            if (debug) {
                ORBUtility.dprint( this,
                    "Exiting exit for POAManagerImpl " + this ) ;
            }
        }
    }

    /** Activate the POAManager if no explicit state change has ever been
     * previously invoked.
     */
    public synchronized void implicitActivation()
    {
        if (!explicitStateChange)
            try {
                activate() ;
            } catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive ai) {
                // ignore the exception.
            }
    }
}