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Java example source code file (ActiveObjectMap.java)

This example Java source code file (ActiveObjectMap.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

activeobjectmap, aomentry, corba, hashmap, hashset, key, map, multipleobjectmap, poaimpl, servant, set, singleobjectmap, stringbuffer, util, wrongpolicy

The ActiveObjectMap.java Java example source code

/*
 * Copyright (c) 1997, 2003, 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.Set ;
import java.util.HashSet ;
import java.util.Map ;
import java.util.HashMap ;
import java.util.Iterator ;
import java.util.Vector ;

import org.omg.PortableServer.Servant ;
import org.omg.PortableServer.POAPackage.WrongPolicy ;
import org.omg.CORBA.INTERNAL ;

/**  The ActiveObjectMap maintains associations between servants and
 * their keys.  There are two variants, to support whether or not
 * multiple IDs per servant are allowed.  This class suppots bidirectional
 * traversal of the key-servant association.  Access to an instance of this
 * class is serialized by the POA mutex.
 */
public abstract class ActiveObjectMap
{
    public static class Key {
        public byte[] id;

        Key(byte[] id) {
            this.id = id;
        }

        public String toString() {
            StringBuffer buffer = new StringBuffer();
            for(int i = 0; i < id.length; i++) {
                buffer.append(Integer.toString((int) id[i], 16));
                if (i != id.length-1)
                    buffer.append(":");
            }
            return buffer.toString();
        }

        public boolean equals(java.lang.Object key) {
            if (!(key instanceof Key))
                return false;
            Key k = (Key) key;
            if (k.id.length != this.id.length)
                return false;
            for(int i = 0; i < this.id.length; i++)
                if (this.id[i] != k.id[i])
                    return false;
            return true;
        }

        // Use the same hash function as for String
        public int hashCode() {
            int h = 0;
            for (int i = 0; i < id.length; i++)
                h = 31*h + id[i];
            return h;
        }
    }

    protected POAImpl poa ;

    protected ActiveObjectMap( POAImpl poa )
    {
        this.poa = poa ;
    }

    public static ActiveObjectMap create( POAImpl poa, boolean multipleIDsAllowed )
    {
        if (multipleIDsAllowed)
            return new MultipleObjectMap( poa ) ;
        else
            return new SingleObjectMap(poa ) ;
    }

    private Map keyToEntry = new HashMap() ;     // Map< Key, AOMEntry >
    private Map entryToServant = new HashMap() ; // Map< AOMEntry, Servant >
    private Map servantToEntry = new HashMap() ; // Map< Servant, AOMEntry >

    public final boolean contains(Servant value)
    {
        return servantToEntry.containsKey( value ) ;
    }

    public final boolean containsKey(Key key)
    {
        return keyToEntry.containsKey(key);
    }

    /** get Returbs the entry assigned to the key, or creates a new
    * entry in state INVALID if none is present.
    */
    public final AOMEntry get(Key key)
    {
        AOMEntry result = (AOMEntry)keyToEntry.get(key);
        if (result == null) {
            result = new AOMEntry( poa ) ;
            putEntry( key, result ) ;
        }

        return result ;
    }

    public final Servant getServant( AOMEntry entry )
    {
        return (Servant)entryToServant.get( entry ) ;
    }

    public abstract Key getKey(AOMEntry value) throws WrongPolicy ;

    public Key getKey(Servant value) throws WrongPolicy
    {
        AOMEntry entry = (AOMEntry)servantToEntry.get( value ) ;
        return getKey( entry ) ;
    }

    protected void putEntry( Key key, AOMEntry value )
    {
        keyToEntry.put( key, value ) ;
    }

    public final void putServant( Servant servant, AOMEntry value )
    {
        entryToServant.put( value, servant ) ;
        servantToEntry.put( servant, value ) ;
    }

    protected abstract void removeEntry( AOMEntry entry, Key key ) ;

    public final void remove( Key key )
    {
        AOMEntry entry = (AOMEntry)keyToEntry.remove( key ) ;
        Servant servant = (Servant)entryToServant.remove( entry ) ;
        if (servant != null)
            servantToEntry.remove( servant ) ;

        removeEntry( entry, key ) ;
    }

    public abstract boolean hasMultipleIDs(AOMEntry value) ;

    protected  void clear()
    {
        keyToEntry.clear();
    }

    public final Set keySet()
    {
        return keyToEntry.keySet() ;
    }
}

class SingleObjectMap extends ActiveObjectMap
{
    private Map entryToKey = new HashMap() ;    // Map< AOMEntry, Key >

    public SingleObjectMap( POAImpl poa )
    {
        super( poa ) ;
    }

    public  Key getKey(AOMEntry value) throws WrongPolicy
    {
        return (Key)entryToKey.get( value ) ;
    }

    protected void putEntry(Key key, AOMEntry value)
    {
        super.putEntry( key, value);

        entryToKey.put( value, key ) ;
    }

    public  boolean hasMultipleIDs(AOMEntry value)
    {
        return false;
    }

    // This case does not need the key.
    protected void removeEntry(AOMEntry entry, Key key)
    {
        entryToKey.remove( entry ) ;
    }

    public  void clear()
    {
        super.clear() ;
        entryToKey.clear() ;
    }
}

class MultipleObjectMap extends ActiveObjectMap
{
    private Map entryToKeys = new HashMap() ;   // Map< AOMEntry, Set< Key > >

    public MultipleObjectMap( POAImpl poa )
    {
        super( poa ) ;
    }

    public  Key getKey(AOMEntry value) throws WrongPolicy
    {
        throw new WrongPolicy() ;
    }

    protected void putEntry(Key key, AOMEntry value)
    {
        super.putEntry( key, value);

        Set set = (Set)entryToKeys.get( value ) ;
        if (set == null) {
            set = new HashSet() ;
            entryToKeys.put( value, set ) ;
        }
        set.add( key ) ;
    }

    public  boolean hasMultipleIDs(AOMEntry value)
    {
        Set set = (Set)entryToKeys.get( value ) ;
        if (set == null)
            return false ;
        return set.size() > 1 ;
    }

    protected void removeEntry(AOMEntry entry, Key key)
    {
        Set keys = (Set)entryToKeys.get( entry ) ;
        if (keys != null) {
            keys.remove( key ) ;
            if (keys.isEmpty())
                entryToKeys.remove( entry ) ;
        }
    }

    public  void clear()
    {
        super.clear() ;
        entryToKeys.clear() ;
    }
}

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