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<html>
<head>
<title>Apache Commons CLI Overview</title>
</head>
<body>
<a href="https://commons.apache.org/cli"> <img src="org/apache/commons/cli/doc-files/logo.png" alt="Apache Commons CLI">
</a>
<section id="Introducing">
<h1>
<img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">1. Introducing Apache Commons CLI
</h1>
<p>The Apache Commons CLI component parses command-line arguments for your application.</p>
<p>Commons CLI parses command-line arguments using a descriptor of
valid options (long and short), potentially with arguments.</p>
<p>Command-line arguments may be of the typical {@code String[]}
form, but also may be a {@code java.util.List}. Indexes allow
for parsing only a portion of the command-line. Also, functionality
for parsing the command-line in phases is built in, allowing for
'cvs-style' command-lines, where some global options are specified
before a 'command' argument, and command-specific options are
specified after the command argument:
</p>
<pre><code>
myApp -p &lt;port&gt; command -p &lt;printer&gt;
</code></pre>
<p>
The homepage for the project is <a href="https://commons.apache.org">Apache Commons</a>
</p>
<p>
There are three stages to command line processing. They are the
definition, parsing and interrogation stages. The following
sections discuss each of these stages in turn, and show how
to implement them with CLI.
</p>
<section>
<h2>Defining the CLI</h2>
<p>
Each command line must define the set of options that will be used
to define the interface to the application.
</p>
<p>
CLI uses the <a href="javadocs/api-release/org/apache/commons/cli/Options.html">
Options</a> class, as a container for
<a href="javadocs/api-release/org/apache/commons/cli/Option.html">
Option</a> instances. There are two ways to create
<code>Option</code>s in CLI. One of them is via the constructors,
the other way is via the factory methods defined in
<code>Options</code>.
</p>
<p>
The <a href="#Using">Usage Scenarios</a> document provides
examples how to create an <code>Options</code> object and also
provides some real world examples.
</p>
<p>
The result of the definition stage is an <code>Options</code>
instance.
</p>
</section>
<section>
<h2>Parsing the CLI</h2>
<p>
The parsing stage is where the text passed into the
application via the command line is processed. The text is
processed according to the rules defined by the parser
implementation.
</p>
<p>
The <code>parse</code> method defined on
<a href="javadocs/api-release/org/apache/commons/cli/CommandLineParser.html">
CommandLineParser</a> takes an <code>Options</code>
instance and a <code>String[]</code> of arguments and
returns a
<a href="javadocs/api-release/org/apache/commons/cli/CommandLine.html">
CommandLine</a>.
</p>
<p>
The result of the parsing stage is a <code>CommandLine</code>
instance.
</p>
</section>
<section>
<h2>Interrogating the CLI</h2>
<p>
The interrogation stage is where the application queries the
<code>CommandLine</code> to decide what execution branch to
take depending on boolean options and uses the option values
to provide the application data.
</p>
<p>
This stage is implemented in the user code. The accessor methods
on <code>CommandLine</code> provide the interrogation capability
to the user code.
</p>
<p>
The result of the interrogation stage is that the user code
is fully informed of all the text that was supplied on the command
line and processed according to the parser and <code>Options</code>
rules.
</p>
</section>
</section>
<section id="Using">
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">2. Using Apache Commons CLI</h1>
<p>
The following sections describe some example scenarios on how to
use CLI in applications.
</p>
<section>
<h2>Using a boolean option</h2>
<p>
A boolean option is represented on a command line by the presence
of the option, i.e. if the option is found then the option value
is <code>true</code>, otherwise the value is <code>false</code>.
</p>
<p>
The <code>DateApp</code> utility prints the current date to standard
output. If the <code>-t</code> option is present the current time is
also printed.
</p>
</section>
<section>
<h2>Creating the Options</h2>
<p>
An <a href="javadocs/api-release/org/apache/commons/cli/Options.html">
Options</a> object must be created and the <code>Option</code> must be
added to it.
</p>
<pre><code>
// create Options object
Options options = new Options();
// add t option
options.addOption("t", false, "display current time");
</code></pre>
<p>
The <code>addOption</code> method has three parameters. The first
parameter is a <code>java.lang.String</code> that represents the option.
The second parameter is a <code>boolean</code> that specifies whether the
option requires an argument or not. In the case of a boolean option
(sometimes referred to as a flag) an argument value is not present so
<code>false</code> is passed. The third parameter is the description
of the option. This description will be used in the usage text of the
application.
</p>
</section>
<section>
<h2>Parsing the command line arguments</h2>
<p>
The <code>parse</code> methods of <code>CommandLineParser</code> are used
to parse the command line arguments. There may be several implementations
of the <code>CommandLineParser</code> interface, the recommended one is the
<code>DefaultParser</code>.
</p>
<code>CommandLineParser parser = new DefaultParser();
CommandLine cmd = parser.parse(options, args);</code>
<p>
Now we need to check if the <code>t</code> option is present. To do
this we will interrogate the
<a href="javadocs/api-release/org/apache/commons/cli/CommandLine.html">CommandLine
</a> object. The <code>hasOption</code> method takes a
<code>java.lang.String</code> parameter and returns <code>true</code> if the option
represented by the <code>java.lang.String</code> is present, otherwise
it returns <code>false</code>.
</p>
<pre><code>if(cmd.hasOption("t")) {
// print the date and time
} else {
// print the date
}</code></pre>
<p>
<em>Note</em>
</p>
<p>
As of version 1.5, the
<code>DefaultParser</code>'s constructor now has an override with
the signature <code>DefaultParser(final boolean allowPartialMatching)</code>.
Given the following code:
<code>final Options options = new Options();
options.addOption(new Option("d", "debug", false, "Turn on debug."));
options.addOption(new Option("e", "extract", false, "Turn on extract."));
options.addOption(new Option("o", "option", true, "Turn on option with argument."));</code>
we define "partial matching" as <code>-de</code> only matching the
<code>"debug"</code> option. We can consequently, now, turn this off and have
<code>-de</code> match both the <code>debug</code> option as well as the
<code>extract</code> option.
</p>
</section>
<section>
<h2>International Time</h2>
<p>
The <code>InternationalDateApp</code> utility extends the
<code>DateApp</code> utility by providing the ability to print the
date and time in any country in the world. To facilitate this a new
command line option, <code>c</code>, has been introduced.
</p>
<pre><code>// add c option
options.addOption("c", true, "country code");</code></pre>
<p>
The second parameter is <code>true</code> this time. This specifies that the
<code>c</code> option requires an argument value. If the required option
argument value is specified on the command line it is returned,
otherwise <code>null</code> is returned.
</p>
</section>
<section>
<h2>Retrieving the argument value</h2>
<p>
The <code>getOptionValue</code> methods of <code>CommandLine</code> are
used to retrieve the argument values of options.
</p>
<pre><code>// get c option value
String countryCode = cmd.getOptionValue("c");
if(countryCode == null) {
// print default date
} else {
// print date for country specified by countryCode
}</code></pre>
</section>
</section>
<section>
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">3. Using Ant as an Example</h1>
<p>
<a href="https://ant.apache.org/">Ant</a> will be used
here to illustrate how to create the <code>Options</code> required. The following
is the help output for Ant.
</p>
<pre><code>ant [options] [target [target2 [target3] ...]]
Options:
-help print this message
-projecthelp print project help information
-version print the version information and exit
-quiet be extra quiet
-verbose be extra verbose
-debug print debugging information
-emacs produce logging information without adornments
-logfile &lt;file&gt; use given file for log
-logger &lt;classname&gt; the class which is to perform logging
-listener &lt;classname&gt; add an instance of class as a project listener
-buildfile &lt;file&gt; use given buildfile
-D&lt;property&gt;=&lt;value&gt; use value for given property
-find &lt;file&gt; search for buildfile towards the root of the
filesystem and use it</code></pre>
<section>
<h2>Defining Boolean Options</h2>
<p>
Lets create the boolean options for the application as they
are the easiest to create. For clarity the constructors for
<code>Option</code> are used here.
</p>
<pre><code>Option help = new Option("help", "print this message");
Option projecthelp = new Option("projecthelp", "print project help information");
Option version = new Option("version", "print the version information and exit");
Option quiet = new Option("quiet", "be extra quiet");
Option verbose = new Option("verbose", "be extra verbose");
Option debug = new Option("debug", "print debugging information");
Option emacs = new Option("emacs",
"produce logging information without adornments");</code></pre>
</section>
<section>
<h2>Defining Argument Options</h2>
<p>
The argument options are created using the <code>Option#Builder</code>.
</p>
<pre><code>Option logFile = Option.builder("logfile")
.argName("file")
.hasArg()
.desc("use given file for log")
.build();
Option logger = Option.builder("logger")
.argName("classname")
.hasArg()
.desc("the class which it to perform logging")
.build();
Option listener = Option.builder("listener")
.argName("classname")
.hasArg()
.desc("add an instance of class as "
+ "a project listener")
.build();
Option buildFile = Option.builder("buildfile")
.argName("file")
.hasArg()
.desc("use given buildfile")
.build();
Option find = Option.builder("find")
.argName("file")
.hasArg()
.desc("search for buildfile towards the "
+ "root of the filesystem and use it")
.build();</code></pre>
</section>
<section>
<h2>Defining Java Property Option</h2>
<p>
The last option to create is the Java property, and it is also created
using the Option class' Builder.
</p>
<code>Option property = Option property = Option.builder("D")
.hasArgs()
.valueSeparator('=')
.build();</code>
<p>
The map of properties specified by this option can later be retrieved by
calling <code>getOptionProperties("D")</code> on the <code>CommandLine</code>.
</p>
</section>
<section>
<h2>Creating the Options</h2>
<p>
Now that we have created each
<a href="javadocs/api-release/org/apache/commons/cli/Option.html">Option</a> we need
to create the
<a href="javadocs/api-release/org/apache/commons/cli/Options.html">Options</a>
instance. This is achieved using the
<a href="javadocs/api-release/org/apache/commons/cli/CommandLine.html#addOption(org.apache.commons.cli.Option)">addOption</a>
method of <code>Options</code>.
</p>
<pre><code>Options options = new Options();
options.addOption(help);
options.addOption(projecthelp);
options.addOption(version);
options.addOption(quiet);
options.addOption(verbose);
options.addOption(debug);
options.addOption(emacs);
options.addOption(logfile);
options.addOption(logger);
options.addOption(listener);
options.addOption(buildfile);
options.addOption(find);
options.addOption(property);</code></pre>
<p>
All the preparation is now complete, and we are now ready to
parse the command line arguments.
</p>
</section>
<section>
<h2>Creating the Parser</h2>
<p>
We now need to create a <code>CommandLineParser</code>. This will parse the command
line arguments, using the rules specified by the <code>Options</code> and
return an instance of <a href="javadocs/api-release/org/apache/commons/cli/CommandLine.html">CommandLine</a>.
</p>
<pre><code>public static void main(String[] args) {
// create the parser
CommandLineParser parser = new DefaultParser();
try {
// parse the command line arguments
CommandLine line = parser.parse(options, args);
} catch (ParseException exp) {
// oops, something went wrong
System.err.println("Parsing failed. Reason: " + exp.getMessage());
}
}</code></pre>
</section>
<section>
<h2>Querying the commandline</h2>
<p>
To see if an option has been passed the <code>hasOption</code>
method is used. The argument value can be retrieved using
the <code>getOptionValue</code> method.
</p>
<pre><code>// has the buildfile argument been passed?
if (line.hasOption("buildfile")) {
// initialize the member variable
this.buildfile = line.getOptionValue("buildfile");
}</code></pre>
</section>
<section>
<h2>Displaying Usage and Help</h2>
<p>
CLI also provides the means to automatically generate usage
and help information. This is achieved with the
<a href="javadocs/api-release/org/apache/commons/cli/HelpFormatter.html">HelpFormatter</a>
class.
</p>
<pre><code>// automatically generate the help statement
HelpFormatter formatter = new HelpFormatter();
formatter.printHelp("ant", options);</code></pre>
<p>
When executed the following output is produced:
</p>
<pre><code>usage: ant
-D &lt;property=value&gt; use value for given property
-buildfile &lt;file&gt; use given buildfile
-debug print debugging information
-emacs produce logging information without adornments
-file &lt;file&gt; search for buildfile towards the root of the
filesystem and use it
-help print this message
-listener &lt;classname&gt; add an instance of class as a project listener
-logger &lt;classname&gt; the class which it to perform logging
-projecthelp print project help information
-quiet be extra quiet
-verbose be extra verbose
-version print the version information and exit</code></pre>
<p>
If you also require to have a usage statement printed
then calling <code>formatter.printHelp("ant", options, true)</code>
will generate a usage statement as well as the help information.
</p>
</section>
</section>
<section>
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">4. Creating an ls Example</h1>
<p>
One of the most widely used command line applications in the *nix world
is <code>ls</code>. Due to the large number of options required for <code>ls</code>
this example will only cover a small proportion of the options. The following
is a section of the help output.
</p>
<pre><code>Usage: ls [OPTION]... [FILE]...
List information about the FILEs (the current directory by default).
Sort entries alphabetically if none of -cftuSUX nor --sort.
-a, --all do not hide entries starting with .
-A, --almost-all do not list implied . and ..
-b, --escape print octal escapes for non-graphic characters
--block-size=SIZE use SIZE-byte blocks
-B, --ignore-backups do not list implied entries ending with ~
-c with -lt: sort by, and show, ctime (time of last
modification of file status information)
with -l: show ctime and sort by name
otherwise: sort by ctime
-C list entries by columns</code></pre>
<p>
The following is the code that is used to create the
<a href="javadocs/api-release/org/apache/commons/cli/Options.html">Options</a> for this example.
</p>
<pre><code>// create the command line parser
CommandLineParser parser = new DefaultParser();
// create the Options
Options options = new Options();
options.addOption("a", "all", false, "do not hide entries starting with .");
options.addOption("A", "almost-all", false, "do not list implied . and ..");
options.addOption("b", "escape", false, "print octal escapes for non-graphic "
+ "characters");
options.addOption(Option.builder("SIZE").longOpt("block-size")
.desc("use SIZE-byte blocks")
.hasArg()
.build());
options.addOption("B", "ignore-backups", false, "do not list implied entries "
+ "ending with ~");
options.addOption("c", false, "with -lt: sort by, and show, ctime (time of last "
+ "modification of file status information) with "
+ "-l:show ctime and sort by name otherwise: sort "
+ "by ctime");
options.addOption("C", false, "list entries by columns");
String[] args = new String[]{ "--block-size=10" };
try {
// parse the command line arguments
CommandLine line = parser.parse(options, args);
// validate that block-size has been set
if (line.hasOption("block-size")) {
// print the value of block-size
System.out.println(line.getOptionValue("block-size"));
}
} catch (ParseException exp) {
System.out.println("Unexpected exception:" + exp.getMessage());
} </code></pre>
</section>
<section>
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">5. Converting (Parsing) Option Values</h1>
<p>
By in most cases the values on the command line are retrieved as Strings via the
<code>commandLine.getOptionValue(key)</code> command. However, it is possible for
the CLI library to convert the string into a different object. For example to specify
that the "count" option should return an Integer the following code could be used:
</p>
<pre><code>
public static void main(String[] args) {
Option count = Option.builder("count")
.hasArg()
.desc("the number of things")
.type(Integer.class)
.build();
Options options = new Options().addOption(count);
// create the parser
CommandLineParser parser = new DefaultParser();
try {
// parse the command line arguments
CommandLine line = parser.parse(options, args);
} catch (ParseException exp) {
// oops, something went wrong
System.err.println("Parsing failed. Reason: " + exp.getMessage());
}
try {
Integer value = line.getParsedOptionValue(count);
System.out.format("The value is %s%n", value );
} catch (ParseException e) {
e.printStackTrace();
}
} </code></pre>
<p>
The value types natively supported by commons-cli are:
</p>
<ul>
<li>Object.class - The string value must be the name of a class with a no argument constructor</li>
<li>Class.class - The string value must be the name of a class</li>
<li>Date.class - The string value must be a date parsable by <code>new SimpleDateFormat("EEE MMM dd HH:mm:ss zzz yyyy")</code></li>
<li>File.class - The string value is the name of the file.</li>
<li>Path.class - The string value is the name of a Path.</li>
<li>Number.class - The string value is a number representation can can be converted into an Integer or a Double.</li>
<li>URL.class - The string value is the textual representation of a URL</li>
<li>FileInputStream.class - The string value is passed to <code>new FileInputStream(s)</code>.</li>
<li>Long.class - The string value is a valid argument to <code>Long.parseLong()</code>.</li>
<li>Integer.class - The string value is a valid argument to <code>Integer.parseInt()</code>.</li>
<li>Short.class - The string value is a valid argument to <code>Short.parseShort()</code>.</li>
<li>Byte.class - The string value is a valid argument to <code>Byte.parseByte()</code>.</li>
<li>Character.class - The string value is either a UTF-8 encoding for a character (e.g. "\\u0124") or the first character from the String."</li>
<li>Double.class - The string value is a valid argument to <code>Double.parseDouble()</code>.</li>
<li>Float.class - The string value is a valid argument to <code>Float.parseFloat()</code>.</li>
<li>BigInteger.class - The string value is a valid argument to <code>new BigInteger(s)</code>.</li>
<li>BigDecimal.class - The string value is a valid argument to <code>new BigDecimal(s)</code>.</li>
</ul>
<p>
Additional types may be added to the automatic parsing system by calling <code>TypeHandler.register(Class&lt;T&gt; clazz, Converter&lt;T&gt; converter)</code>.
The <code>Class&lt;T&gt;</code> can be any defined class. The converter is a function that takes a <code>String</code> argument and returns an instance of
the class. Any exception thrown by the constructor will be caught and reported as a <code>ParseException</code>
</p>
<p>
Conversions can be specified without using the <code>TypeHandler</code> class by specifying the converter
directly during the option build. For example:
</p>
<pre><code>
Option fooOpt = Option.builder("foo")
.hasArg()
.desc("the foo arg")
.converter(Foo::new)
.build();</code></pre>
<p>
The above will create an option that passes the string value to the Foo constructor when <code>commandLine.getParsedOptionValue(fooOpt)</code> is called.
</p>
<p>
Conversions that are added to the TypeHandler or that are specified directly will not deserialize if the option is serialized unless the type is registered with the TypeHandler
before deserialization begins.
</p>
</section>
<section>
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">6. Deprecating Options</h1>
<p>
Options may be marked as deprecated using ghe <code>Option.builder.deprecated()</code> method.
Additional information may be specified by passing a <code>DeprecatedAttributes</code> instance to the
<code>deprecated</code> method.
Usage of the deprecated option is announced when the presence of the option is checked
or the value of the option is retrieved. By default, the announcement printed to Standard out.
The HelpFormatter output will by default show the description prefixed by "[Deprecated]"
</p>
<p>
The examples below will implement <code>doSomething</code> in the following code block.
</p>
<pre><code>
public static void main(String[] args) {
Option n = Option.builder("n")
.deprecated(DeprecatedAttributes.builder()
.setDescription("Use '-count' instead")
.setForRemoval(true)
.setSince("now").get())
.hasArg()
.desc("the number of things")
.type(Integer.class)
.build();
Option count = Option.builder("count")
.hasArg()
.desc("the number of things")
.type(Integer.class)
.build();
Options options = new Options().addOption(n).addOption(count);
doSomething(options);
} </code></pre>
<section>
<h2>Changing Usage Announcement</h2>
<p>
The usage announcement may be changed by providing a <code>Consumer&lt;Option&gt;</code> to the
<code>CommandLine.Builder.deprecatedHandler</code> method. This is commonly used to log usage
of deprecated options rather than printing them on the standard output.
</p>
<p>
for example if <code>doSomething</code> is implemented as:
</p>
<pre><code>
void doSomething(Options options) {
CommandLineParser parser = new DefaultParser();
CommandLine line;
try {
// parse the command line arguments
line = parser.parse(options, new String[] {"-n", "5"});
System.out.println("n=" + line.getParsedOptionValue("n"));
} catch (ParseException exp) {
// oops, something went wrong
System.err.println("Parsing failed. Reason: " + exp.getMessage());
}
} </code></pre>
<p>
The output of the run would be.
</p>
<pre><code>
Option 'n': Deprecated for removal since now: Use '-count' instead
n=5 </code></pre>
<p>
for example if <code>doSomething</code> is implemented as:
</p>
<pre><code>
void doSomething(Options options) {
Consumer&lt;Option&gt; deprecatedUsageAnnouncement = o -&gt; {
final StringBuilder buf = new StringBuilder()
.append("'")
.append(o.getOpt())
.append("'");
if (o.getLongOpt() != null) {
buf.append("'").append(o.getLongOpt()).append("'");
}
System.err.printf("ERROR: Option %s: %s%n", buf, o.getDeprecated());
};
DefaultParser parser = DefaultParser.builder().setDeprecatedHandler(deprecatedUsageAnnouncement).build();
CommandLine line;
try {
// parse the command line arguments
line = parser.parse(options, new String[] {"-n", "5"});
System.out.println("n=" + line.getParsedOptionValue("n"));
} catch (ParseException exp) {
// oops, something went wrong
System.err.println("Parsing failed. Reason: " + exp.getMessage());
}
} </code></pre>
<p>
The output of the run would be.
</p>
<code>
ERROR: Option 'n': Deprecated for removal since now: Use '-count' instead
n=5 </code>
<p>
However, the first line would be printed on system err instead of system out.
</p>
</section>
<section>
<h2>Changing help format</h2>
<p>By default the help formater prints "[Deprecated]" in front of the description for the option. This can
be changed to display any values desired.
</p>
<p>
If <code>doSomething</code> is implemented as:
</p>
<pre><code>
void doSomething(Options options) {
HelpFormatter formatter = HelpFormatter.builder().get();
formatter.printHelp("Command line syntax:", options);
} </code></pre>
<p>
To output is
</p>
<pre><code>
usage: Command line syntax:
-count &lt;arg&gt; the number of things
-n &lt;arg&gt; [Deprecated] the number of things</code></pre>
<p>
The display of deprecated options may be changed through the use of the
<code>HelpFormatter.Builder.setShowDeprecated()</code> method.
</p>
<ul>
<li>Calling <code>HelpFormatter.Builder.setShowDeprecated(false)</code> will disable the "[Deprecated]" tag.</li>
<li>Calling <code>HelpFormatter.Builder.setShowDeprecated</code> with a <code>Function&lt;Option, String&gt;</code>
will use the output of the function as the description for the option.</li>
</ul>
<p>
As an example of the second case above, changing the implementation of <code>doSomething</code> to
</p>
<pre><code>
void doSomething(Options options) {
Function&lt;Option, String&gt; disp = option -&gt; String.format("%s. %s", HelpFormatter.getDescription(option),
option.getDeprecated().toString());
HelpFormatter formatter = HelpFormatter.builder().setShowDeprecated(disp).get();
formatter.printHelp("Command line syntax:", options);
} </code></pre>
<p>
changes the output to
</p>
<pre><code>
usage: Command line syntax:
-count &lt;arg&gt; the number of things
-n &lt;arg&gt; the number of things. Deprecated for removal since now:
Use '-count' instead</code></pre>
</section>
</section>
<section id="Properties">
<h1><img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">7. Defining Option Properties</h1>
<p>
The following are the properties that each
<a href="javadocs/api-release/org/apache/commons/cli/Option.html">Option</a> has. All of these
can be set using the accessors or using the methods
defined in the
<a href="javadocs/api-release/org/apache/commons/cli/Option.Builder.html">Option.Builder</a>.
</p>
<table>
<caption>Option Properties</caption>
<tr>
<th>Name</th>
<th>Type</th>
<th>Description</th>
</tr>
<tr>
<td>arg</td>
<td>boolean</td>
<td>A flag to say whether the option takes an argument.</td>
</tr>
<tr>
<td>args</td>
<td>boolean</td>
<td>A flag to say whether the option takes more than one argument.</td>
</tr>
<tr>
<td>argName</td>
<td>java.lang.String</td>
<td>The name of the argument value for the usage statement.</td>
</tr>
<tr>
<td>converter</td>
<td>org.apache.commons.cli.Converter&lt;T, E extends Throwable&gt;</td>
<td>A FunctionalInterface that converts a String to type T and may throw an exception E. When
CommandLine.getParsedValue() is called this FunctionalInterface will perform the conversion from the
command line argument to the parsed type. This is used when a desired type is not registered, or to
provide a custom type implementation. The 'type' property is not required to use the 'converter' property.</td>
</tr>
<tr>
<td>deprecated</td>
<td>org.apache.commons.cli.DeprecatedAttributes</td>
<td>Marks the option as deprecated and has the deprecation properties.</td>
</tr>
<tr>
<td>description</td>
<td>java.lang.String</td>
<td>A description of the function of the option.</td>
</tr>
<tr>
<td>longOpt</td>
<td>java.lang.String</td>
<td>An alias and more descriptive identification string. May be null or not specified if 'opt' is provided.</td>
</tr>
<tr>
<td>opt</td>
<td>java.lang.String</td>
<td>The identification string of the Option. May be null or not specified if 'longOpt' is provided.</td>
</tr>
<tr>
<td>optionalArg</td>
<td>boolean</td>
<td>A flag to say whether the option's argument is optional.</td>
</tr>
<tr>
<td>required</td>
<td>boolean</td>
<td>A flag to say whether the option <b>must</b> appear on the command line.</td>
</tr>
<tr>
<td>type</td>
<td>java.lang.Class&lt;?&gt;</td>
<td>The class of the object returned from getParsedValue(). The class must be registered in TypeHandler instance.
See also 'converter' property.</td>
</tr>
<tr>
<td>value</td>
<td>java.lang.String</td>
<td>The value of the option.</td>
</tr>
<tr>
<td>values</td>
<td>java.lang.String[]</td>
<td>The values of the option.</td>
</tr>
<tr>
<td>valueSeparator</td>
<td>char</td>
<td>The character value used to split the argument string, that is used in conjunction with multipleArgs e.g.
if the separator is ',' and the argument string is 'a,b,c' then there are three argument values, 'a', 'b'
and 'c'.</td>
</tr>
</table>
</section>
<h1>
<img src="org/apache/commons/cli/doc-files/leaf.svg" style="height: 1em; padding-right: 0.25em" alt="leaf">8. Requirements
</h1>
<ul>
<li>Java 8 or above.</li>
<li>If using OSGi, R7 or above.</li>
</ul>
</body>