org.apache.sqoop.shell.HelpCommand.java Source code

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Here is the source code for org.apache.sqoop.shell.HelpCommand.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.sqoop.shell;

import java.text.MessageFormat;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;

import org.apache.commons.lang.StringUtils;
import org.apache.sqoop.common.SqoopException;
import org.apache.sqoop.shell.core.ShellError;
import org.apache.sqoop.shell.core.Constants;
import org.codehaus.groovy.tools.shell.Command;
import org.codehaus.groovy.tools.shell.CommandSupport;
import org.codehaus.groovy.tools.shell.Shell;
import org.codehaus.groovy.tools.shell.util.SimpleCompletor;

import static org.apache.sqoop.shell.ShellEnvironment.*;

public class HelpCommand extends CommandSupport {

    protected HelpCommand(Shell shell) {
        super(shell, Constants.CMD_HELP, Constants.CMD_HELP_SC);
    }

    @Override
    public String getDescription() {
        return resourceString(Constants.RES_HELP_DESCRIPTION);
    }

    @Override
    public String getUsage() {
        return resourceString(Constants.RES_HELP_USAGE);
    }

    @Override
    public String getHelp() {
        return resourceString(Constants.RES_HELP_MESSAGE);
    }

    @SuppressWarnings("rawtypes")
    @Override
    public Object execute(List args) {
        if (args.size() == 0) {
            list();
        } else {
            help((String) args.get(0));
        }
        return null;
    }

    @SuppressWarnings("unchecked")
    private void list() {
        Iterator<Command> iterator;

        // Figure out the max command name and shortcut length dynamically
        int maxName = 0;
        int maxShortcut = 0;
        iterator = shell.getRegistry().commands().iterator();
        while (iterator.hasNext()) {
            Command command = iterator.next();
            if (command.getHidden()) {
                continue;
            }

            if (command.getName().length() > maxName) {
                maxName = command.getName().length();
            }

            if (command.getShortcut().length() > maxShortcut) {
                maxShortcut = command.getShortcut().length();
            }
        }

        printlnResource(Constants.RES_HELP_INFO);
        println();

        // List the commands we know about
        printlnResource(Constants.RES_HELP_AVAIL_COMMANDS);

        iterator = shell.getRegistry().commands().iterator();
        while (iterator.hasNext()) {
            Command command = iterator.next();
            if (command.getHidden()) {
                continue;
            }

            String paddedName = StringUtils.rightPad(command.getName(), maxName);
            String paddedShortcut = StringUtils.rightPad(command.getShortcut(), maxShortcut);

            String description = command.getDescription();

            StringBuilder sb = new StringBuilder();
            sb.append("  ").append(MessageFormat.format(resource.getString(Constants.RES_HELP_CMD_DESCRIPTION),
                    paddedName, paddedShortcut, description));
            println(sb.toString());
        }

        println();
        printlnResource(Constants.RES_HELP_SPECIFIC_CMD_INFO);
        println();
    }

    private void help(String name) {
        Command command = shell.getRegistry().find(name);
        if (command == null) {
            String msg = MessageFormat.format(resource.getString(Constants.RES_UNRECOGNIZED_CMD), name);
            throw new SqoopException(ShellError.SHELL_0001, msg);
        }
        printlnResource(Constants.RES_HELP_CMD_USAGE, command.getName(), command.getUsage());
        println();
        println(command.getHelp());
        println();
    }

    @SuppressWarnings({ "rawtypes", "unchecked" })
    protected List createCompletors() {
        SimpleCompletor completor = new SimpleCompletor();
        Iterator<Command> iterator = registry.iterator();
        while (iterator.hasNext()) {
            Command command = iterator.next();
            if (command.getHidden()) {
                continue;
            }

            completor.add(command.getName());
        }

        List completors = new LinkedList();
        completors.add(completor);
        return completors;
    }
}