/*
 * 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.zookeeper.server.quorum;

/**
 * This class encapsulates the state comparison logic. Specifically,
 * how two different states are compared.
 */
public class StateSummary {

    private long currentEpoch;
    private long lastZxid;

    public StateSummary(long currentEpoch, long lastZxid) {
        this.currentEpoch = currentEpoch;
        this.lastZxid = lastZxid;
    }

    public long getCurrentEpoch() {
        return currentEpoch;
    }

    public long getLastZxid() {
        return lastZxid;
    }

    public boolean isMoreRecentThan(StateSummary ss) {
        return (currentEpoch > ss.currentEpoch) || (currentEpoch == ss.currentEpoch && lastZxid > ss.lastZxid);
    }

    @Override
    public boolean equals(Object obj) {
        if(!(obj instanceof StateSummary)) {
            return false;
        }
        StateSummary ss = (StateSummary) obj;
        return currentEpoch == ss.currentEpoch && lastZxid == ss.lastZxid;
    }

    @Override
    public int hashCode() {
        return (int) (currentEpoch ^ lastZxid);
    }

}
