org.apache.hadoop.fs.shell.FsCommand.java Source code

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Here is the source code for org.apache.hadoop.fs.shell.FsCommand.java

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/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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 org.apache.hadoop.fs.shell;

import java.io.IOException;
import java.util.LinkedList;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FsShellPermissions;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.shell.find.Find;

import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DEFAULT_NAME_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.FS_DEFAULT_NAME_KEY;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_SHELL_MISSING_DEFAULT_FS_WARNING_DEFAULT;
import static org.apache.hadoop.fs.CommonConfigurationKeysPublic.HADOOP_SHELL_MISSING_DEFAULT_FS_WARNING_KEY;

/**
 * Base class for all "hadoop fs" commands.
 */

@InterfaceAudience.Private
@InterfaceStability.Evolving

// this class may not look useful now, but it's a placeholder for future
// functionality to act as a registry for fs commands.  currently it's being
// used to implement unnecessary abstract methods in the base class

abstract public class FsCommand extends Command {
    /**
     * Register the command classes used by the fs subcommand
     * @param factory where to register the class
     */
    public static void registerCommands(CommandFactory factory) {
        factory.registerCommands(AclCommands.class);
        factory.registerCommands(CopyCommands.class);
        factory.registerCommands(Count.class);
        factory.registerCommands(Delete.class);
        factory.registerCommands(Display.class);
        factory.registerCommands(Find.class);
        factory.registerCommands(FsShellPermissions.class);
        factory.registerCommands(FsUsage.class);
        factory.registerCommands(Ls.class);
        factory.registerCommands(Mkdir.class);
        factory.registerCommands(MoveCommands.class);
        factory.registerCommands(SetReplication.class);
        factory.registerCommands(Stat.class);
        factory.registerCommands(Tail.class);
        factory.registerCommands(Head.class);
        factory.registerCommands(Test.class);
        factory.registerCommands(TouchCommands.class);
        factory.registerCommands(Truncate.class);
        factory.registerCommands(SnapshotCommands.class);
        factory.registerCommands(XAttrCommands.class);
    }

    protected FsCommand() {
    }

    protected FsCommand(Configuration conf) {
        super(conf);
    }

    // historical abstract method in Command
    @Override
    public String getCommandName() {
        return getName();
    }

    // abstract method that normally is invoked by runall() which is
    // overridden below
    @Override
    protected void run(Path path) throws IOException {
        throw new RuntimeException("not supposed to get here");
    }

    /** @deprecated use {@link Command#run(String...argv)} */
    @Deprecated
    @Override
    public int runAll() {
        return run(args);
    }

    @Override
    protected void processRawArguments(LinkedList<String> args) throws IOException {
        LinkedList<PathData> expendedArgs = expandArguments(args);
        // If "fs.defaultFs" is not set appropriately, it warns the user that the
        // command is not running against HDFS.
        final boolean displayWarnings = getConf().getBoolean(HADOOP_SHELL_MISSING_DEFAULT_FS_WARNING_KEY,
                HADOOP_SHELL_MISSING_DEFAULT_FS_WARNING_DEFAULT);
        if (displayWarnings) {
            final String defaultFs = getConf().get(FS_DEFAULT_NAME_KEY);
            final boolean missingDefaultFs = defaultFs == null || defaultFs.equals(FS_DEFAULT_NAME_DEFAULT);
            if (missingDefaultFs) {
                err.printf("Warning: fs.defaultFS is not set when running \"%s\" command.%n", getCommandName());
            }
        }
        processArguments(expendedArgs);
    }
}