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 * Licensed to Elasticsearch under one or more contributor
 * license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright
 * ownership. Elasticsearch 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.elasticsearch.indices.recovery;

import org.elasticsearch.Version;
import org.elasticsearch.common.io.stream.StreamInput;
import org.elasticsearch.common.io.stream.StreamOutput;
import org.elasticsearch.index.seqno.SequenceNumbers;
import org.elasticsearch.transport.FutureTransportResponseHandler;
import org.elasticsearch.transport.TransportResponse;
import org.elasticsearch.transport.TransportResponseHandler;

import java.io.IOException;

public class RecoveryTranslogOperationsResponse extends TransportResponse {

    long localCheckpoint;

    RecoveryTranslogOperationsResponse() {

    }

    RecoveryTranslogOperationsResponse(final long localCheckpoint) {
        this.localCheckpoint = localCheckpoint;
    }

    @Override
    public void writeTo(final StreamOutput out) throws IOException {
        // before 6.0.0 we responded with an empty response so we have to maintain that
        if (out.getVersion().onOrAfter(Version.V_6_0_0_alpha1)) {
            out.writeZLong(localCheckpoint);
        }
    }

    @Override
    public void readFrom(final StreamInput in) throws IOException {
        // before 6.0.0 we received an empty response so we have to maintain that
        if (in.getVersion().onOrAfter(Version.V_6_0_0_alpha1)) {
            localCheckpoint = in.readZLong();
        }
        else {
            localCheckpoint = SequenceNumbers.UNASSIGNED_SEQ_NO;
        }
    }

    static TransportResponseHandler<RecoveryTranslogOperationsResponse> HANDLER =
            new FutureTransportResponseHandler<RecoveryTranslogOperationsResponse>() {
                @Override
                public RecoveryTranslogOperationsResponse read(StreamInput in) throws IOException {
                    RecoveryTranslogOperationsResponse response = new RecoveryTranslogOperationsResponse();
                    response.readFrom(in);
                    return response;
                }
            };

}
