ParameterSpecification.java

/*
 * Copyright (c) 2015 Spotify AB.
 *
 * 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 com.spotify.heroic;

import lombok.Data;

import java.io.PrintWriter;
import java.text.BreakIterator;
import java.util.Locale;
import java.util.Optional;

@Data
public class ParameterSpecification {
    private final String name;
    private final String description;
    private final Optional<String> metavar;

    public static ParameterSpecification parameter(String name, String description) {
        return new ParameterSpecification(name, description, Optional.empty());
    }

    public static ParameterSpecification parameter(
        String name, String description, String metavar
    ) {
        return new ParameterSpecification(name, description, Optional.of(metavar));
    }

    public void printHelp(
        final PrintWriter out, final String prefix, final int width
    ) {
        printHelp(out, prefix, width, Optional.empty());
    }

    public void printHelp(
        final PrintWriter out, final String prefix, final int width, final Optional<String> scope
    ) {
        final String p = prefix + scope.map(s -> s + ".").orElse("");

        if (metavar.isPresent()) {
            out.println(p + name + "=" + metavar.get());
        } else {
            out.println(p + name);
        }

        printWrapped(out, prefix + "    ", width, description);
    }

    public static void printWrapped(
        final PrintWriter out, final String prefix, final int width, final String doc
    ) {
        final BreakIterator boundary = BreakIterator.getLineInstance(Locale.US);
        boundary.setText(doc);

        int start = boundary.first();
        int end = boundary.next();
        int line = prefix.length();

        final int maxWidth = width - prefix.length();

        out.print(prefix);

        while (end != BreakIterator.DONE) {
            final String word = doc.substring(start, end);

            line = line + word.length();

            if (line >= maxWidth) {
                out.println();
                out.print(prefix);
                line = word.length() + prefix.length();
            }

            out.print(word);
            start = end;
            end = boundary.next();
        }

        out.println();
    }
}