/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * Copyright (c) 2008, Red Hat Middleware LLC or third-party contributors as
 * indicated by the @author tags or express copyright attribution
 * statements applied by the authors.  All third-party contributions are
 * distributed under license by Red Hat Middleware LLC.
 *
 * This copyrighted material is made available to anyone wishing to use, modify,
 * copy, or redistribute it subject to the terms and conditions of the GNU
 * Lesser General Public License, as published by the Free Software Foundation.
 *
 * This program 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 Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this distribution; if not, write to:
 * Free Software Foundation, Inc.
 * 51 Franklin Street, Fifth Floor
 * Boston, MA  02110-1301  USA
 */
package org.hibernate.envers.entities.mapper;
import java.util.Map;
import org.hibernate.envers.tools.Pair;

/**
 * Data describing the change of a single object in a persistent collection (when the object was added, removed or
 * modified in the collection).
 * @author Adam Warski (adam at warski dot org)
 */
public class PersistentCollectionChangeData {
    private final String entityName;
    private final Map<String, Object> data;
    private final Object changedElement;

    public PersistentCollectionChangeData(String entityName, Map<String, Object> data, Object changedElement) {
        this.entityName = entityName;
        this.data = data;
        this.changedElement = changedElement;
    }

    /**
     *
     * @return Name of the (middle) entity that holds the collection data.
     */
    public String getEntityName() {
        return entityName;
    }

    public Map<String, Object> getData() {
        return data;
    }

    /**
     * @return The affected element, which was changed (added, removed, modified) in the collection.
     */
    public Object getChangedElement() {
        if (changedElement instanceof Pair) {
            return ((Pair) changedElement).getSecond();
        }

        if (changedElement instanceof Map.Entry) {
            return ((Map.Entry) changedElement).getValue();
        }

        return changedElement;
    }

    /**
     * @return Index of the affected element, or {@code null} if the collection isn't indexed.
     */
    public Object getChangedElementIndex() {
        if (changedElement instanceof Pair) {
            return ((Pair) changedElement).getFirst();
        }

        if (changedElement instanceof Map.Entry) {
            return ((Map.Entry) changedElement).getKey();
        }

        return null;
    }
}