io.zeebe.logstreams.impl.snapshot.fs.FsTemporarySnapshotWriter Maven / Gradle / Ivy

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/*
 * Copyright © 2017 camunda services GmbH ([email protected])
 *
 * 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 io.zeebe.logstreams.impl.snapshot.fs;

import java.io.File;
import java.nio.file.Files;
import java.nio.file.StandardCopyOption;

/**
 * Extends FsSnapshotWriter, delegating the write of the checksum + data to it,
 * and moving the data file to its correct path at the end.
 *
 * In this respect, dataFile => temporaryFile, and snapshotFile is the correct
 * final destination.
 */
public class FsTemporarySnapshotWriter extends FsSnapshotWriter
{
    private File snapshotFile;

    @SuppressWarnings("WeakerAccess")
    public FsTemporarySnapshotWriter(final FsSnapshotStorageConfiguration config,
        final File temporaryFile,
        final File checksumFile,
        final File snapshotFile)
    {
        super(config, temporaryFile, checksumFile, null);
        this.snapshotFile = snapshotFile;
    }

    @Override
    public void commit() throws Exception
    {
        try
        {
            super.commit();

            // TODO: evaluate if REPLACE_EXISTING is safe here
            Files.move(dataFile.toPath(), snapshotFile.toPath(), StandardCopyOption.ATOMIC_MOVE, StandardCopyOption.REPLACE_EXISTING);
            //noinspection ResultOfMethodCallIgnored
            dataFile.delete();
        }
        catch (final Exception ex)
        {
            abort();
            throw ex;
        }
    }

    @SuppressWarnings("ResultOfMethodCallIgnored")
    @Override
    public void abort()
    {
        super.abort();
        snapshotFile.delete();
    }

    @Override
    protected String getDataFileName()
    {
        return snapshotFile.getName();
    }

    public File getSnapshotFile()
    {
        return snapshotFile;
    }
}