dxabstractmap.java

用Java写的面相对象的数据库管理系统

// You can redistribute this software and/or modify it under the terms of
// the Ozone Library License version 1 published by ozone-db.org.
//
// The original code and portions created by SMB are
// Copyright (C) 1997-2000 by SMB GmbH. All rights reserved.
//
// $Id: DxAbstractMap.java,v 1.9 2000/10/28 16:55:14 daniela Exp $

package org.ozoneDB.DxLib;

import java.io.*;

/**
 * 
 * 
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.9 $Date: 2000/10/28 16:55:14 $
 */
public abstract class DxAbstractMap extends DxAbstractCollection implements DxMap, Externalizable {
    
    final static long serialVersionUID = 1L;
    
    
    public Object clone( DxMap newMap ) {
        try {
            DxIterator it = iterator();
            Object obj;
            while ((obj = it.next()) != null) {
                newMap.addForKey( obj, it.key() );
            } 
            return newMap;
        } catch (Exception e) {
            throw new RuntimeException( e.toString() );
        } 
    } 
    
    
    public DxCollection valueClone() {
        throw new RuntimeException( getClass().getName() + ".valueClone() not implemented." );
    } 
    
    
    /**
     * Compares two maps for equality. Returns true if the keySets are
     * equal.
     */
    public boolean equals( Object obj ) {
        if (obj != null && obj instanceof DxMap) {
            DxMap rhs = (DxMap)obj;
            if (this == obj) {
                return true;
            } 
            // FIXME: direct call to DxSet.equlas() is "ambigous"...
            Object keySet = keySet();
            return keySet.equals( rhs.keySet() );
        } else {
            return false;
        } 
    } 
    
    
    public synchronized boolean add( Object obj ) {
        return addForKey( obj, buildKey( obj ) );
    } 
    
    
    public synchronized boolean addAll( DxCollection coll ) {
        if (coll instanceof DxMap) {
            boolean answer = false;
            DxIterator it = coll.iterator();
            Object obj;
            while ((obj = it.next()) != null) {
                if (addForKey( obj, it.key() )) {
                    answer = true;
                } 
            } 
            return answer;
        } else {
            return super.addAll( coll );
        } 
    } 
    
    
    public synchronized boolean removeAllKeys( DxCollection coll ) {
        boolean answer = false;
        if (!coll.isEmpty() && !isEmpty()) {
            DxIterator it = coll.iterator();
            Object key;
            while ((key = it.next()) != null) {
                if (removeForKey( key ) != null) {
                    answer = true;
                } 
            } 
        } 
        return answer;
    } 
    
    
    /**
     * This method is not declared abstract because it does not need to
     * be implemented in any case.
     */
    public Object buildKey( Object obj ) {
        return obj;
    // throw new RuntimeException ("buildKey(): subclass responsibility");
    } 
    
    
    public boolean containsKey( Object key ) {
        return elementForKey( key ) != null;
    } 
    
    
    public DxSet keySet() {
        DxSet answer = new DxHashSet();
        DxIterator it = iterator();
        while (it.next() != null) {
            answer.add( it.key() );
        } 
        return answer;
    } 
    
    
    public DxSet elementSet() {
        DxSet answer = new DxHashSet();
        answer.addAll( this );
        return answer;
    } 
    
    
    public void writeExternal( ObjectOutput out ) throws IOException {
        // System.out.println (getClass().getName() + ".writeExternal()...");
        out.writeInt( count() );
        DxIterator it = iterator();
        Object obj;
        while ((obj = it.next()) != null) {
            out.writeObject( obj );
            out.writeObject( it.key() );
        } 
    } 
    
    
    public synchronized void readExternal( ObjectInput in ) throws IOException, ClassNotFoundException {
        // System.out.println ("abstract.readExternal()...");
        int count = in.readInt();
        for (; count > 0; count--) {
            addForKey( in.readObject(), in.readObject() );
        } 
    } 
    
}