core/src/org/apache/pivot/util/Vote.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to you 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 org.apache.pivot.util;

/**
 * Enumeration representing a vote. Votes are often used to determine the
 * result of an event preview.
 */
public enum Vote {
    /**
     * Represents an approval vote.
     */
    APPROVE,

    /**
     * Represents a denial vote.
     */
    DENY,

    /**
     * Represents a deferred vote, implying that the vote will be approved later.
     */
    DEFER;

    public Vote tally(Vote vote) {
        if (vote == null) {
            throw new IllegalArgumentException();
        }

        Vote tally;

        switch(vote) {
            case APPROVE: {
                tally = this;
                break;
            }

            case DENY: {
                tally = vote;
                break;
            }

            case DEFER: {
                tally = (this == DENY) ? this : vote;
                break;
            }

            default: {
                throw new IllegalArgumentException();
            }
        }

        return tally;
    }
}