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A Linux shell-like interface to interact with Alluxio
There is a newer version: 1.8.1
/*
 * The Alluxio Open Foundation licenses this work under the Apache License, version 2.0
 * (the “License”). You may not use this work except in compliance with the License, which is
 * available at www.apache.org/licenses/LICENSE-2.0
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
 * either express or implied, as more fully set forth in the License.
 *
 * See the NOTICE file distributed with this work for information regarding copyright ownership.
 */

package alluxio.shell.command;

import alluxio.AlluxioURI;
import alluxio.Configuration;
import alluxio.Constants;
import alluxio.client.ReadType;
import alluxio.client.file.FileInStream;
import alluxio.client.file.FileSystem;
import alluxio.client.file.URIStatus;
import alluxio.client.file.options.OpenFileOptions;
import alluxio.exception.AlluxioException;

import com.google.common.io.Closer;
import org.apache.commons.cli.CommandLine;

import java.io.IOException;
import java.util.List;

import javax.annotation.concurrent.ThreadSafe;

/**
 * Loads a file or directory in Alluxio space, makes it resident in memory.
 */
@ThreadSafe
public final class LoadCommand extends WithWildCardPathCommand {

  /**
   * Constructs a new instance to load a file or directory in Alluxio space.
   *
   * @param conf the configuration for Alluxio
   * @param fs the filesystem of Alluxio
   */
  public LoadCommand(Configuration conf, FileSystem fs) {
    super(conf, fs);
  }

  @Override
  public String getCommandName() {
    return "load";
  }

  @Override
  void runCommand(AlluxioURI path, CommandLine cl) throws IOException {
    load(path);
  }

  /**
   * Loads a file or directory in Alluxio space, makes it resident in memory.
   *
   * @param filePath The {@link AlluxioURI} path to load into Alluxio memory
   * @throws IOException if a non-Alluxio related exception occurs
   */
  private void load(AlluxioURI filePath) throws IOException {
    try {
      URIStatus status = mFileSystem.getStatus(filePath);
      if (status.isFolder()) {
        List statuses = mFileSystem.listStatus(filePath);
        for (URIStatus uriStatus : statuses) {
          AlluxioURI newPath = new AlluxioURI(uriStatus.getPath());
          load(newPath);
        }
      } else {
        if (status.getInMemoryPercentage() == 100) {
          // The file has already been fully loaded into Alluxio memory.
          return;
        }
        Closer closer = Closer.create();
        try {
          OpenFileOptions options = OpenFileOptions.defaults().setReadType(ReadType.CACHE_PROMOTE);
          FileInStream in = closer.register(mFileSystem.openFile(filePath, options));
          byte[] buf = new byte[8 * Constants.MB];
          while (in.read(buf) != -1) {
          }
        } catch (Exception e) {
          throw closer.rethrow(e);
        } finally {
          closer.close();
        }
      }
      System.out.println(filePath + " loaded");
    } catch (AlluxioException e) {
      throw new IOException(e.getMessage());
    }
  }

  @Override
  public String getUsage() {
    return "load ";
  }

  @Override
  public String getDescription() {
    return "Loads a file or directory in Alluxio space, makes it resident in memory.";
  }
}