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package oracle.toplink.essentials.internal.sessions;

import java.util.*;

/**
 * <p>
 * <b>Purpose</b>: This class holds the record of the changes made to a collection attribute of
 * an object.
 * <p>
 * <b>Description</b>: Collections must be compared to each other and added and removed objects must
 * be recorded seperately.
 *
 * NOTE: This class and its sub class are currently not used within TopLink and should be removed.
 */
public class OrderedCollectionChangeRecord extends ChangeRecord implements oracle.toplink.essentials.changesets.OrderedCollectionChangeRecord {
    protected Hashtable addObjectList;
    protected Vector addIndexes;
    protected int startIndexOfRemove;

    /**
     * This constructor returns a changeRecord representing the DirectCollection mapping
     * @param owner prototype.changeset.ObjectChangeSet that ObjectChangeSet that uses this record
     */
    public OrderedCollectionChangeRecord(ObjectChangeSet owner) {
        this.owner = owner;
        this.startIndexOfRemove = Integer.MAX_VALUE;
    }

    /**
     * This method takes a hastable of primitive objects and adds them to the add list.
     */
    public void addAdditionChange(Hashtable additions, Vector indexes, UnitOfWorkChangeSet changes, AbstractSession session) {
        for (Enumeration enumtr = additions.keys(); enumtr.hasMoreElements();) {
            Object index = enumtr.nextElement();
            Object object = additions.get(index);
            Object changeSet = session.getDescriptor(object.getClass()).getObjectBuilder().createObjectChangeSet(object, changes, session);
            additions.put(index, changeSet);
        }

        this.addObjectList = additions;
        this.addIndexes = indexes;
    }

    /**
     * This method returns the collection of indexes in which changes were made to this collection.
     */
    public Vector getAddIndexes() {
        if (this.addIndexes == null) {
            this.addIndexes = new Vector(1);
        }
        return addIndexes;
    }

    /**
     * This method returns the collection of ChangeSets that were added to the collection.
     */
    public Hashtable getAddObjectList() {
        if (this.addObjectList == null) {
            this.addObjectList = new Hashtable(1);
        }
        return addObjectList;
    }

    /**
     * This method returns the index from where objects must be removed from the collection
     */
    public int getStartRemoveIndex() {
        return this.startIndexOfRemove;
    }

    /**
     * INTERNAL:
     * This method will be used to merge one record into another
     */
    public void mergeRecord(ChangeRecord mergeFromRecord, UnitOfWorkChangeSet mergeToChangeSet, UnitOfWorkChangeSet mergeFromChangeSet) {
        // NOTE: if this class is ever used then this method will need to be implemented
    }

    /**
     * This method sets the index from where objects must be removed from the collection
     */
    public void setStartRemoveIndex(int startRemoveIndex) {
        this.startIndexOfRemove = startRemoveIndex;
    }

    /**
     * INTERNAL:
     * This method will be used to update the objectsChangeSets references
     */
    public void updateReferences(UnitOfWorkChangeSet mergeToChangeSet, UnitOfWorkChangeSet mergeFromChangeSet) {
        //if this class is ever used this method will need to be implemented
    }
}