Java tutorial
/** * Licensed to Cloudera, Inc. under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. Cloudera, Inc. 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.cloudera.sqoop.cli; import java.io.PrintWriter; import java.io.StringWriter; import java.util.ArrayList; import java.util.Iterator; import java.util.List; import org.apache.commons.cli.HelpFormatter; import org.apache.commons.cli.Option; import org.apache.commons.cli.Options; /** * Class that holds several sets of related options, providing a container * for all the options associated with a single tool. * The order in which sets of related options are added to this tool is * preserved in printing and iteration. */ public class ToolOptions implements Iterable<RelatedOptions> { private List<RelatedOptions> optGroups; public ToolOptions() { this.optGroups = new ArrayList<RelatedOptions>(); } /** * Add a block of related options to the options for this tool. * @param opts the set of RelatedOptions to add. */ public void addOptions(RelatedOptions opts) { optGroups.add(opts); } /** * Add a block of related options to the options for this tool, * if a block has not already been added with the same title. * @param opts the set of RelatedOptions to add. */ public void addUniqueOptions(RelatedOptions opts) { if (!containsGroup(opts.getTitle())) { optGroups.add(opts); } } /** * Reports whether this collection of RelatedOptions contains * a RelatedOptions with the specified title. * @param title the group title to search for * @return true if a RelatedOptions with this group title is * in the collection. */ public boolean containsGroup(String title) { for (RelatedOptions related : this) { if (related.getTitle().equals(title)) { return true; } } return false; } /** * Provide an iterator over all sets of RelatedOptions. * @return an iterator returning each RelatedOptions element. */ public Iterator<RelatedOptions> iterator() { return optGroups.iterator(); } /** * Flatten the different sets of related options into a single collection * of options. * @return all options in the ToolOptions as a single set */ public Options merge() { Options mergedOpts = new Options(); int totalOpts = 0; for (RelatedOptions relatedOpts : this) { for (Object optObj : relatedOpts.getOptions()) { Option opt = (Option) optObj; mergedOpts.addOption(opt); totalOpts++; } } return mergedOpts; } /** * Print the help to the console using a default help formatter. */ public void printHelp() { printHelp(new HelpFormatter()); } /** * Print the help to the console using the specified help formatter. * @param formatter the HelpFormatter to use. */ public void printHelp(HelpFormatter formatter) { printHelp(formatter, new PrintWriter(System.out, true)); } /** * Print the help to the specified PrintWriter, using the specified * help formatter. * @param formatter the HelpFormatter to use. * @param pw the PrintWriter to emit to. */ public void printHelp(HelpFormatter formatter, PrintWriter pw) { boolean first = true; for (RelatedOptions optGroup : optGroups) { if (!first) { pw.println(""); } pw.println(optGroup.getTitle() + ":"); formatter.printOptions(pw, formatter.getWidth(), optGroup, 0, 4); first = false; } } @Override public String toString() { StringWriter sw = new StringWriter(); printHelp(new HelpFormatter(), new PrintWriter(sw)); sw.flush(); return sw.getBuffer().toString(); } }