net.dharwin.common.tools.cli.api.defaultcommands.HelpCommand Maven / Gradle / Ivy

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package net.dharwin.common.tools.cli.api.defaultcommands;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;

import net.dharwin.common.tools.cli.api.CLIContext;
import net.dharwin.common.tools.cli.api.Command;
import net.dharwin.common.tools.cli.api.CommandResult;
import net.dharwin.common.tools.cli.api.annotations.CLICommand;
import net.dharwin.common.tools.cli.api.console.Console;
import net.dharwin.common.tools.cli.api.utils.CommandUtils;


import com.beust.jcommander.Parameter;

/**
 * Prints all known commands. A parameter "c" can be specified to print the
 * usage for a specific command.
 * @author Sean
 * 
 */
@CLICommand(name = "help", description = "Prints known commands and usage.")
public class HelpCommand extends Command {

    @Parameter(names = { "-c", "--command" }, description = "The command name to get specific help for.")
    private String _commandName;

    @Override
	public CommandResult innerExecute(CLIContext context) {
		if (_commandName == null) {
			// Print command list.
			Set knownCommandsSet = context.getHostApplication().getCommandNames();
			
			List knownCommands = new ArrayList(knownCommandsSet);
			Collections.sort(knownCommands);
			
			Map commandHelpMap = new HashMap();
			
			// Find the longest command name and description.
            // Used in formatting.
            int longestCommandName = 0;
            int longestDescription = 0;
			
			// Create a map of command name to description, while also
            // finding the longest command name/description.
			for (String commandName : knownCommands) {
			    if (commandName.length() > longestCommandName) {
                    longestCommandName = commandName.length();
                }
			    Class> c =
			        CommandUtils.getCommandClass(
			            context, commandName);
			    
			    String description = c.getAnnotation(CLICommand.class).description();
			    if (description.length() > longestDescription) {
			        longestDescription = description.length();
			    }
			    commandHelpMap.put(commandName, description);
			}
			
			Console.info("Known commands:");
			for (String command : knownCommands) {
			    String desc = commandHelpMap.get(command);
			    if (desc == null) {
			        desc = "";
			    }
			    Console.info(String.format(getOutputString(command,
			                desc, longestCommandName,
			                longestDescription),
			            command, desc));
			}
		}
		else {
			// Print help for a specific command.
			Command command = null;
			try {
				Class> commandClass =
				    CommandUtils.getCommandClass(
	                        context, _commandName);
				if (commandClass == null) {
					Console.error("Command ["+_commandName+"] not recognized.");
					return CommandResult.BAD_ARGS;
				}
				command = commandClass.newInstance();
			}
			catch (Exception e) {
				Console.error("Error loading command help for ["+_commandName+"].");
				return CommandResult.ERROR;
			}
			
			command.usage();
		}
		
		return CommandResult.OK;
	}

    /**
     * Get a format string for a help line.
     * This creates a string formattable to two columns, where the column
     * widths are dictated by the column width (calculated above as max
     * command name/description sizes). The columns are separated by two tabs
     * with a colon in the middle.
     * @param commandName The command name.
     * @param description The command description.
     * @param nameColWidth The column width for the name column.
     * @param descColWidth The column width for the description column.
     * @return
     */
    private String getOutputString(String commandName, String description,
            int nameColWidth, int descColWidth) {
        return new StringBuilder().append("%1$-").append(nameColWidth)
                .append("s\t:\t%2$-").append(descColWidth).append("s").toString();
    }

}