com.github.dmyersturnbull.transformations.CommandLineHelper.java Source code

Introduction

Here is the source code for com.github.dmyersturnbull.transformations.CommandLineHelper.java

Source

/*
   Copyright 2015 PharmGKB
         2015 Douglas Myers-Turnbull
    
   Licensed 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 com.github.dmyersturnbull.transformations;

import org.apache.commons.cli.CommandLine;
import org.apache.commons.cli.DefaultParser;
import org.apache.commons.cli.HelpFormatter;
import org.apache.commons.cli.Option;
import org.apache.commons.cli.Options;
import org.apache.commons.cli.ParseException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.io.PrintWriter;
import java.lang.invoke.MethodHandles;
import java.util.HashSet;
import java.util.Optional;
import java.util.Set;

/**
 * A skeleton Apache Commons CLI handler.
 * @author Douglas Myers-Turnbull
 */
public class CommandLineHelper {

    private static final Logger sf_logger = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());

    private static final int sf_helpWidth = 120;

    private Optional<Class<?>> m_class; // null is NOT ok; probably Class<? extends DataTransformation>
    private String m_helpHeader; // null is ok
    private String m_helpFooter; // null is ok
    private Options m_options = new Options();

    private Set<String> m_shortNames;
    private Set<String> m_longNames;

    public CommandLineHelper() {
        m_class = Optional.empty();
        m_options.addOption("h", "help", false, "Print usage");
        m_shortNames = new HashSet<>();
        m_longNames = new HashSet<>();
    }

    @Nonnull
    public CommandLineHelper setClass(@Nullable Class<?> aClass) {
        m_class = Optional.ofNullable(aClass);
        return this;
    }

    @Nonnull
    public CommandLineHelper setHelpHeader(@Nullable String helpHeader) {
        m_helpHeader = helpHeader;
        return this;
    }

    @Nonnull
    public CommandLineHelper setHelpFooter(@Nullable String helpFooter) {
        m_helpFooter = helpFooter;
        return this;
    }

    @Nonnull
    public CommandLineHelper addOptions(@Nonnull Option... additionalOptions) {
        for (Option option : additionalOptions) {
            m_options.addOption(option);
            if (m_shortNames.contains(option.getOpt())) {
                throw new IllegalArgumentException("Option with short name " + option.getOpt() + " already exists");
            }
            m_shortNames.add(option.getOpt());
            if (option.getLongOpt() != null) {
                if (m_longNames.contains(option.getLongOpt())) {
                    throw new IllegalArgumentException(
                            "Option with long name " + option.getLongOpt() + " already exists");
                }
                m_longNames.add(option.getLongOpt());
            }
        }
        return this;
    }

    /**
     *
     * @return {@code Optional.empty()} if the command line should not be run, or the values parsed otherwise
     */
    @Nonnull
    public Optional<ExtendedCommandLine> parse(@Nonnull String... args) {

        ExtendedCommandLine cli;

        try {

            CommandLine x = new DefaultParser().parse(m_options, args);
            cli = new ExtendedCommandLine(x);

        } catch (ParseException e) {
            sf_logger.error("Couldn't parse command-line arguments", e);
            printHelp(FileTransformationUtils.stderr());
            return Optional.empty();
        }

        if (cli.has("h")) {
            printHelp(FileTransformationUtils.stdout());
            return Optional.empty();
        } else {
            return Optional.of(cli);
        }
    }

    public void printHelp() {
        printHelp(FileTransformationUtils.stderr());
    }

    public void printHelp(@Nonnull PrintWriter pw) {
        HelpFormatter formatter = new HelpFormatter();
        formatter.printHelp(pw, sf_helpWidth, m_class.map(Class::getSimpleName).orElse("<unknown class>"),
                m_helpHeader, m_options, 0, 0, m_helpFooter, true);
        pw.flush();
    }

}