com.google.cloud.hadoop.fs.gcs.InMemoryGoogleHadoopFileSystem.java Source code

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Here is the source code for com.google.cloud.hadoop.fs.gcs.InMemoryGoogleHadoopFileSystem.java

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/**
 * Copyright 2014 Google Inc. All Rights Reserved.
 *
 *  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 com.google.cloud.hadoop.fs.gcs;

import com.google.cloud.hadoop.gcsio.GoogleCloudStorageFileSystem;
import com.google.cloud.hadoop.gcsio.testing.InMemoryGoogleCloudStorage;
import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import org.apache.hadoop.conf.Configuration;
import org.junit.Assert;

/**
 * Helper class to create an in-memory GHFS from an in-memory GcsFs instance for testing only.
 */
public class InMemoryGoogleHadoopFileSystem extends GoogleHadoopFileSystem {
    // The in-memory GcsFs instance to be used.
    private static GoogleCloudStorageFileSystem inMemoryGcsFs = createUnderlyingStorage();

    /**
     * Default constructor. Should only be called after createUnderlyingStorage has been called.
     *
     * @throws IOException on IO Error.
     */
    public InMemoryGoogleHadoopFileSystem() throws IOException {
        super(inMemoryGcsFs);
        initialize();
    }

    /**
     * Sets the GcsFs to be used. This should be called before an instance is constructed in order to
     * create a GCS storage over which to run the in-memory GHFS.
     */
    private static synchronized GoogleCloudStorageFileSystem createUnderlyingStorage() {
        try {
            if (inMemoryGcsFs == null) {
                return new GoogleCloudStorageFileSystem(new InMemoryGoogleCloudStorage());
            } else {
                return inMemoryGcsFs;
            }
        } catch (IOException e) {
            Assert.fail("Could not initialize in-memory Google Cloud Storage.");
        }
        return null;
    }

    /**
     * Returns a sample Hadoop job configuration to be used for testing.
     *
     * @return a sample Hadoop Configuration for in-memory GHFS.
     * @throws IOException on IO Error.
     */
    public static Configuration getSampleConfiguration() throws IOException {
        // Set the Hadoop job configuration.
        Configuration config = new Configuration();
        config.set("fs.gs.impl", InMemoryGoogleHadoopFileSystem.class.getName());
        String systemBucketName = "test-system-bucket";
        config.set(GoogleHadoopFileSystemBase.GCS_SYSTEM_BUCKET_KEY, systemBucketName);
        config.setBoolean(GoogleHadoopFileSystemBase.GCS_CREATE_SYSTEM_BUCKET_KEY, true);
        return config;
    }

    /**
     * Initializes this in-memory GHFS for testing.
     *
     * @throws IOException on IO Error.
     */
    private void initialize() throws IOException {
        // Initialize the GoogleHadoopFileSystemBase.
        URI initUri;
        try {
            initUri = new URI("gs://test_bucket/");
        } catch (URISyntaxException e) {
            this.close();
            throw new IllegalArgumentException(e);
        }
        this.initialize(initUri, getSampleConfiguration());
    }
}