MapAdapter.java

/*******************************************************************************
 * Copyright (c) 1998, 2015 Oracle and/or its affiliates. All rights reserved.
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Oracle - initial API and implementation from Oracle TopLink
******************************************************************************/
package org.eclipse.persistence.tools.workbench.utility.diff;

import java.util.Iterator;
import java.util.Map;

/**
 * This adapter assumes that two containers are Maps.
 * Use a map entry differentiator to compare the entries' values.
 */
public class MapAdapter
    implements ContainerDifferentiator.Adapter
{

    // singleton
    private static MapAdapter INSTANCE;

    /**
     * Return the singleton.
     */
    public static synchronized MapAdapter instance() {
        if (INSTANCE == null) {
            INSTANCE = new MapAdapter();
        }
        return INSTANCE;
    }

    /**
     * Allow subclasses.
     */
    protected MapAdapter() {
        super();
    }

    /**
     * @see ContainerDifferentiator.Adapter#diffIsFatal(Object, Object)
     */
    public boolean diffIsFatal(Object object1, Object object2) {
        if ( ! (object1 instanceof Map)) {
            return true;
        }
        if ( ! (object2 instanceof Map)) {
            return true;
        }
        return false;
    }

    /**
     * @see ContainerDifferentiator.Adapter#containerClass()
     */
    public Class containerClass() {
        return Map.class;
    }

    /**
     * @see ContainerDifferentiator.Adapter#size(Object)
     */
    public int size(Object container) {
        return ((Map) container).size();
    }

    /**
     * @see ContainerDifferentiator.Adapter#iterator(Object)
     */
    public Iterator iterator(Object container) {
        return ((Map) container).entrySet().iterator();
    }

    /**
     * @see Object#toString()
     */
    public String toString() {
        return "MapAdapter";
    }

}