vaadin-framework/shared/src/main/java/com/vaadin/shared/data/sort/SortDirection.java

/*
 * Copyright 2000-2014 Vaadin Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.vaadin.shared.data.sort;

import java.io.Serializable;

/**
 * Describes sorting direction.
 * 
 * @since 7.4
 * @author Vaadin Ltd
 */
public enum SortDirection implements Serializable {

    /**
     * Ascending (e.g. A-Z, 1..9) sort order
     */
    ASCENDING {
        @Override
        public SortDirection getOpposite() {
            return DESCENDING;
        }
    },

    /**
     * Descending (e.g. Z-A, 9..1) sort order
     */
    DESCENDING {
        @Override
        public SortDirection getOpposite() {
            return ASCENDING;
        }
    };

    /**
     * Get the sort direction that is the direct opposite to this one.
     * 
     * @return a sort direction value
     */
    public abstract SortDirection getOpposite();
}