/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.server.helpers;

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Transaction;

public class Transactor {

    private final org.neo4j.server.helpers.UnitOfWork unitOfWork;
    private final GraphDatabaseService graphDb;
    private final int attempts; // how many times to try, if the transaction fails for some reason

    public Transactor(GraphDatabaseService graphDb, UnitOfWork unitOfWork) {
        this(graphDb, unitOfWork, 1);
    }

    public Transactor(GraphDatabaseService graphDb, UnitOfWork unitOfWork, int attempts) {
        assert attempts > 0 : "The Transactor should make at least one attempt at running the transaction.";
        this.unitOfWork = unitOfWork;
        this.graphDb = graphDb;
        this.attempts = attempts;
    }

    public void execute() {
        for (int attemptsLeft = attempts - 1; attemptsLeft >= 0; attemptsLeft--) {
            try (Transaction tx = graphDb.beginTx()) {
                unitOfWork.doWork(tx);
                tx.commit();
            } catch (RuntimeException e) {
                if (attemptsLeft == 0) {
                    throw e;
                }
            }
        }
    }
}
