ozoneodmgdbag.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: OzoneODMGDBag.java,v 1.4 2000/10/28 16:55:19 daniela Exp $

package org.ozoneDB.odmg;

import org.odmg.*;
//import org.ozoneDB.*;
import java.util.*;


/**
 * @author <a href="http://www.softwarebuero.de/">SMB</a>
 * @version $Revision: 1.4 $Date: 2000/10/28 16:55:19 $
 */
public class OzoneODMGDBag extends ArrayList implements DBag {
    
    
    public OzoneODMGDBag() {
        super();
    }
    
    
    public OzoneODMGDBag( Collection _collection ) {
        super( _collection );
    }
    
    
    /**
     * A new <code>DBag</code> instance is created that is the union of this object
     * and <code>otherBag</code>.
     * This method is similar to the <code>addAll</code> method in <code>Collection</code>,
     * except that this method creates a new collection and <code>addAll</code>
     * modifies the object to contain the result.
     * @param    otherBag    The other bag to use in the union operation.
     * @return A <code>DBag</code> instance that contains the union of this object
     * and <code>otherBag</code>.
     */
    // * @see   com.sun.java.util.collections.Collection#addAll
    public DBag union( DBag otherBag ) {
        DBag result = new OzoneODMGDBag( this );
        result.addAll( otherBag );
        return result;
    } 
    
    
    /**
     * A new <code>DBag</code> instance is created that contains the intersection of
     * this object and the <code>DBag</code> referenced by <code>otherBag</code>.
     * This method is similar to the <code>retainAll</code> method in <code>Collection</code>,
     * except that this method creates a new collection and <code>retainAll</code>
     * modifies the object to contain the result.
     * @param    otherBag The other bag to use in creating the intersection.
     * @return A <code>DBag</code> instance that contains the intersection of this
     * object and <code>otherBag</code>.
     */
    // @see com.sun.java.util.collections.Collection#retainAll
    public DBag intersection( DBag otherBag ) {
        DBag result = new OzoneODMGDBag();
        return result;
    } 
    
    
    /**
     * A new <code>DBag</code> instance is created that contains the difference of
     * this object and the <code>DBag</code> instance referenced by <code>otherBag</code>.
     * This method is similar to the <code>removeAll</code> method in <code>Collection</code>,
     * except that this method creates a new collection and <code>removeAll</code>
     * modifies the object to contain the result.
     * @param    otherBag The other bag to use in creating the difference.
     * @return A <code>DBag</code> instance that contains the elements of this object
     * minus the elements in <code>otherBag</code>.
     */
    // * @see com.sun.java.util.collections.Collection#removeAll
    public DBag difference( DBag otherBag ) {
        DBag result = union( otherBag );
        result.removeAll( otherBag );
        result.removeAll( this );
        return result;
    } 
    
    
    /**
     * This method returns the number of occurrences of the object <code>obj</code>
     * in the <code>DBag</code> collection.
     * @param obj The value that may have elements in the collection.
     * @return The number of occurrences of <code>obj</code> in this collection.
     */
    public int occurrences( Object obj ) {
        int result = 0;
        if (obj != null) {
            for (int i = 0, size = size(); i < size; ++i) {
                if (obj.equals( get( i ) )) {
                    ++result;
                } 
            } 
        } 
        return result;
    } 
    
    
    /**
     * NOT SUPPORTED!
     */
    public Object selectElement( String predicate ) throws QueryInvalidException {
        throw new NotImplementedException( "OQL not supported" );
    } 
    
    
    /**
     * NOT SUPPORTED!
     */
    public java.util.Iterator select( String predicate ) throws QueryInvalidException {
        throw new NotImplementedException( "OQL not supported" );
    } 
    
    
    /**
     * NOT SUPPORTED!
     */
    public DCollection query( String predicate ) throws QueryInvalidException {
        throw new NotImplementedException( "OQL not supported" );
    } 
    
    
    /**
     * NOT SUPPORTED!
     */
    public boolean existsElement( String predicate ) throws QueryInvalidException {
        throw new NotImplementedException( "OQL not supported" );
    } 
    
}