alluxio.shell.AlluxioShell.java Source code

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Here is the source code for alluxio.shell.AlluxioShell.java

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/*
 * 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;

import alluxio.Configuration;
import alluxio.Constants;
import alluxio.client.file.FileSystem;
import alluxio.shell.command.ShellCommand;
import alluxio.util.CommonUtils;

import com.google.common.base.Throwables;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Maps;
import org.apache.commons.cli.CommandLine;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.reflections.Reflections;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.Closeable;
import java.io.IOException;
import java.lang.reflect.Modifier;
import java.util.Arrays;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;

import javax.annotation.concurrent.NotThreadSafe;

/**
 * Class for handling command line inputs.
 */
@NotThreadSafe
public class AlluxioShell implements Closeable {
    private static final Logger LOG = LoggerFactory.getLogger(Constants.LOGGER_TYPE);
    private static final Map<String, String[]> CMD_ALIAS = ImmutableMap.<String, String[]>builder()
            .put("chgrpr", new String[] { "chgrp", "-R" }).put("chmodr", new String[] { "chmod", "-R" })
            .put("chownr", new String[] { "chown", "-R" }).put("lsr", new String[] { "ls", "-R" })
            .put("rmr", new String[] { "rm", "-R" }).build();

    /**
     * Main method, starts a new AlluxioShell.
     *
     * @param argv [] Array of arguments given by the user's input from the terminal
     * @throws IOException if closing the shell fails
     */
    public static void main(String[] argv) throws IOException {
        AlluxioShell shell = new AlluxioShell(new Configuration());
        int ret;
        try {
            ret = shell.run(argv);
        } finally {
            shell.close();
        }
        System.exit(ret);
    }

    private final Map<String, ShellCommand> mCommands = Maps.newHashMap();
    private final Configuration mConfiguration;
    private final FileSystem mFileSystem;

    /**
     * @param configuration the configuration for Alluxio
     */
    public AlluxioShell(Configuration configuration) {
        mConfiguration = configuration;
        mFileSystem = FileSystem.Factory.get();
        loadCommands();
    }

    @Override
    public void close() throws IOException {
    }

    /**
     * Uses reflection to get all the {@link ShellCommand} classes and store them in a map.
     */
    private void loadCommands() {
        String pkgName = ShellCommand.class.getPackage().getName();
        Reflections reflections = new Reflections(pkgName);
        for (Class<? extends ShellCommand> cls : reflections.getSubTypesOf(ShellCommand.class)) {
            // Only instantiate a concrete class
            if (!Modifier.isAbstract(cls.getModifiers())) {
                ShellCommand cmd;
                try {
                    cmd = CommonUtils.createNewClassInstance(cls,
                            new Class[] { Configuration.class, FileSystem.class },
                            new Object[] { mConfiguration, mFileSystem });
                } catch (Exception e) {
                    throw Throwables.propagate(e);
                }
                mCommands.put(cmd.getCommandName(), cmd);
            }
        }
    }

    /**
     * Gets the replacement command for alias.
     *
     * @param cmd the name of the command
     * @return replacement command if cmd is an alias
     */
    private String[] getReplacementCmd(String cmd) {
        if (CMD_ALIAS.containsKey(cmd)) {
            return CMD_ALIAS.get(cmd);
        } else {
            return null;
        }
    }

    /**
     * Method which prints the method to use all the commands.
     */
    private void printUsage() {
        System.out.println("Usage: java AlluxioShell");
        SortedSet<String> sortedCmds = new TreeSet<String>(mCommands.keySet());
        for (String cmd : sortedCmds) {
            System.out.format("%-60s%-95s%n", "       [" + mCommands.get(cmd).getUsage() + "]   ",
                    mCommands.get(cmd).getDescription());
        }
    }

    /**
     * Method which determines how to handle the user's request, will display usage help to the user
     * if command format is incorrect.
     *
     * @param argv [] Array of arguments given by the user's input from the terminal
     * @return 0 if command is successful, -1 if an error occurred
     */
    public int run(String... argv) {
        if (argv.length == 0) {
            printUsage();
            return -1;
        }

        // Sanity check on the number of arguments
        String cmd = argv[0];
        ShellCommand command = mCommands.get(cmd);

        if (command == null) { // Unknown command (we didn't find the cmd in our dict)
            String[] replacementCmd = getReplacementCmd(cmd);
            if (replacementCmd == null) {
                System.out.println(cmd + " is an unknown command.\n");
                printUsage();
                return -1;
            }
            // Handle command alias, and print out WARNING message for deprecated cmd.
            String deprecatedMsg = "WARNING: " + cmd + " is deprecated. Please use "
                    + StringUtils.join(replacementCmd, " ") + " instead.";
            System.out.println(deprecatedMsg);
            LOG.warn(deprecatedMsg);

            String[] replacementArgv = (String[]) ArrayUtils.addAll(replacementCmd,
                    ArrayUtils.subarray(argv, 1, argv.length));
            return run(replacementArgv);
        }

        String[] args = Arrays.copyOfRange(argv, 1, argv.length);
        CommandLine cmdline = command.parseAndValidateArgs(args);
        if (cmdline == null) {
            printUsage();
            return -1;
        }

        // Handle the command
        try {
            command.run(cmdline);
            return 0;
        } catch (IOException e) {
            System.out.println(e.getMessage());
            LOG.error("Error running " + StringUtils.join(argv, " "), e);
            return -1;
        }
    }
}