alluxio.cli.AbstractShell.java Source code

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Here is the source code for alluxio.cli.AbstractShell.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.cli;

import alluxio.exception.status.InvalidArgumentException;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.Closeable;
import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import java.util.Map;
import java.util.SortedSet;
import java.util.TreeSet;

import javax.annotation.Nullable;
import javax.annotation.concurrent.NotThreadSafe;

/**
 * Abstract class for handling command line inputs.
 */
@NotThreadSafe
public abstract class AbstractShell implements Closeable {
    private static final Logger LOG = LoggerFactory.getLogger(AbstractShell.class);

    private Map<String, String[]> mCommandAlias;
    private Map<String, Command> mCommands;

    /**
     * Creates a new instance of {@link AbstractShell}.
     *
     * @param commandAlias replacements for commands
     */
    public AbstractShell(Map<String, String[]> commandAlias) {
        mCommands = loadCommands();
        mCommandAlias = commandAlias;
    }

    /**
     * Handles the specified shell command request, displaying usage if the command format is invalid.
     *
     * @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];
        Command command = mCommands.get(cmd);

        if (command == null) {
            String[] replacementCmd = getReplacementCmd(cmd);
            if (replacementCmd == null) {
                // Unknown command (we didn't find the cmd in our dict)
                System.err.println(String.format("%s is an unknown command.", cmd));
                printUsage();
                return -1;
            } else {
                // 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);

                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;
        try {
            cmdline = command.parseAndValidateArgs(args);
        } catch (InvalidArgumentException e) {
            System.out.println("Usage: " + command.getUsage());
            LOG.error("Invalid arguments for command {}:", command.getCommandName(), e);
            return -1;
        }

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

    /**
     * @return all commands provided by this shell
     */
    public Collection<Command> getCommands() {
        return mCommands.values();
    }

    @Override
    public void close() throws IOException {
    }

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

    /**
     * @return name of the shell
     */
    protected abstract String getShellName();

    /**
     * Map structure: Command name => {@link Command} instance.
     *
     * @return a set of commands which can be executed under this shell
     */
    protected abstract Map<String, Command> loadCommands();

    /**
     * Prints usage for all commands.
     */
    protected void printUsage() {
        System.out.println("Usage: alluxio " + getShellName() + " [generic options]");
        SortedSet<String> sortedCmds = new TreeSet<>(mCommands.keySet());
        for (String cmd : sortedCmds) {
            System.out.format("%-60s%n", "\t [" + mCommands.get(cmd).getUsage() + "]");
        }
    }
}