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</div><div id='content' class='page-1'><div class='row'><div class='row-fluid'><div class='col-lg-3'><ul class='nav-sidebar'><li><a href='./'>Blog index</a></li><li class='active'><a href='#doc'>Apache Groovy 2.5 CliBuilder Renewal</a></li><li><a href='#_the_code_groovy_util_clibuilder_code_class_is_deprecated' class='anchor-link'>The <code>groovy.util.CliBuilder</code> Class is Deprecated</a></li><li><a href='#_typed_options' class='anchor-link'>Typed Options</a></li><li><a href='#_annotations' class='anchor-link'>Annotations</a></li><li><a href='#_typed_positional_parameters' class='anchor-link'>Typed Positional Parameters</a></li><li><a href='#_apache_commons_cli_features' class='anchor-link'>Apache Commons CLI Features</a></li><li><a href='#_picocli_clibuilder_features' class='anchor-link'>Picocli CliBuilder Features</a></li><li><a href='#_gotchas_incompatibilities' class='anchor-link'>Gotchas/Incompatibilities</a></li><li><a href='#_conclusion' class='anchor-link'>Conclusion</a></li></ul><br/><ul class='nav-sidebar'><li style='padding: 0.35em 0.625em; background-color: #eee'><span>Related posts</span></li><li><a href='./groovy-2-5-7-released'>Groovy 2.5.7 Released</a></li><li><a href='./groovy-2-5-5-windows'>Groovy 2.5.5 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-2-5-4-released'>Groovy 2.5.4 Released</a></li><li><a href='./groovy-2-5-0-released'>Groovy 2.5.0 released</a></li><li><a href='./groovy-2-5-5-released'>Groovy 2.5.5 released</a></li><li><a href='./groovy-2-5-6-released'>Groovy 2.5.6 Released</a></li><li><a href='./groovy-2-5-3-windows'>Groovy 2.5.3 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-2-5-3-released'>Groovy 2.5.3 Released</a></li><li><a href='./groovy-2-5-1-released'>Groovy 2.5.1 released</a></li><li><a href='./groovy-2-5-2-windows'>Groovy 2.5.2 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-2-5-2-released'>Groovy 2.5.2 released</a></li><li><a href='./groovy-2-5-7-and'>Groovy 2.5.7 and 3.0.0-beta-1 Windows Installers Released (Community Artifacts)</a></li><li><a href='./groovy-2-5-4-windows'>Groovy 2.5.4 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-2-4-16-released'>Groovy 2.4.16 Released</a></li><li><a href='./groovy-2-4-16-windows'>Groovy 2.4.16 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-3-0-0-beta'>Groovy 3.0.0-beta-1 Released</a></li><li><a href='./groovy-3-0-0-alpha'>Groovy 3.0.0-alpha-4 Released</a></li><li><a href='./groovy-release-train-4-0'>Groovy release train: 4.0.4, 3.0.12, 2.5.18</a></li><li><a href='./groovy-3-0-0-beta2'>Groovy 3.0.0-beta-2 Windows Installer Released (Community Release)</a></li><li><a href='./groovy-3-0-0-alpha1'>Groovy 3.0.0-alpha-4 Windows Installer Released (Community Artifact)</a></li><li><a href='./groovy-2-4-17-released'>Groovy 2.4.17 Released</a></li><li><a href='./gmavenplus-1-6-2-released'>GMavenPlus 1.6.2 Released (Community Artifact)</a></li><li><a href='./groovy-3-0-0-beta1'>Groovy 3.0.0-beta-2 Released</a></li><li><a href='./groovy-4-0-3-released'>Groovy 4.0.3 Released</a></li></ul></div><div class='col-lg-8 col-lg-pull-0'><a name='doc'></a><h1>Apache Groovy 2.5 CliBuilder Renewal</h1><p><span>Author: <i>Remko Popma</i></span><br/><span>Published: 2018-05-30 11:28AM</span></p><hr/><div id="preamble">
<div class="sectionbody">
<div class="paragraph">
<p>The <code>CliBuilder</code> class for quickly and concisely building
command-line applications has been renewed in Apache Groovy 2.5.
This article highlights what is new.</p>
</div>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/CliBuilder2.5-cygwin.png" alt="CliBuilder2.5 cygwin">
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_the_code_groovy_util_clibuilder_code_class_is_deprecated">The <code>groovy.util.CliBuilder</code> Class is Deprecated</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Previous versions of CliBuilder used Apache <a href="https://commons.apache.org/proper/commons-cli/index.html">Commons CLI</a> as the underlying parser library.
From Groovy 2.5, there is an alternative version of CliBuilder based on the <a href="https://github.com/remkop/picocli">picocli</a> parser.</p>
</div>
<div class="paragraph">
<p>It is recommended that applications explicitly import either <code>groovy.cli.picocli.CliBuilder</code> or <code>groovy.cli.commons.CliBuilder</code>. The <code>groovy.util.CliBuilder</code> class is deprecated and delegates to the Commons CLI version for backwards compatibility.</p>
</div>
<div class="paragraph">
<p>New features will likely only be added to the picocli version, and <code>groovy.util.CliBuilder</code> may be removed in a future version of Groovy.
The Commons CLI version is intended for applications that rely on the internals of the Commons CLI implementation of CliBuilder and cannot easily migrate to the picocli version.</p>
</div>
<div class="paragraph">
<p>Next, let&#8217;s look at some new features in Groovy 2.5 CliBuilder.</p>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_typed_options">Typed Options</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/Type.jpg" alt="Type">
</div>
</div>
<div class="paragraph">
<p>Options can be boolean flags or they can take one or more option parameters.
In previous versions of CliBuilder, you would have to specify <code>args: 1</code> for options that need a parameter, or
<code>args: &#39;+&#39;</code> for options that accept multiple parameters.</p>
</div>
<div class="paragraph">
<p>This version of CliBuilder adds support for typed options. This is convenient when processing parse results,
but additionally, the number of arguments is inferred from the type,
so if the <code>type</code> is specified, <code>args</code> can be omitted.</p>
</div>
<div class="paragraph">
<p>For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">def cli = new CliBuilder()
cli.a(type: String, &#39;a-arg&#39;)
cli.b(type: boolean, &#39;b-arg&#39;)
cli.c(type: Boolean, &#39;c-arg&#39;)
cli.d(type: int, &#39;d-arg&#39;)
cli.e(type: Long, &#39;e-arg&#39;)
cli.f(type: Float, &#39;f-arg&#39;)
cli.g(type: BigDecimal, &#39;g-arg&#39;)
cli.h(type: File, &#39;h-arg&#39;)
cli.i(type: RoundingMode, &#39;i-arg&#39;)
def argz = &#39;&#39;&#39;-a John -b -d 21 -e 1980 -f 3.5 -g 3.14159
-h cv.txt -i DOWN and some more&#39;&#39;&#39;.split()
def options = cli.parse(argz)
assert options.a == &#39;John&#39;
assert options.b
assert !options.c
assert options.d == 21
assert options.e == 1980L
assert options.f == 3.5f
assert options.g == 3.14159
assert options.h == new File(&#39;cv.txt&#39;)
assert options.i == RoundingMode.DOWN
assert options.arguments() == [&#39;and&#39;, &#39;some&#39;, &#39;more&#39;]
</code></pre>
</div>
</div>
<div class="sect2">
<h3 id="_supported_types">Supported Types</h3>
<div class="paragraph">
<p>The Commons CLI-based CliBuilder supports primitives, numeric types, files, enums and arrays thereof
(using <a href="http://docs.groovy-lang.org/2.5.0-SNAPSHOT/html/gapi/index.html?org/codehaus/groovy/runtime/StringGroovyMethods.html#asType">StringGroovyMethods#asType(String, Class)</a>).
The picocli-based CliBuilder supports those <a href="http://picocli.info/#_built_in_types">and more</a>.</p>
</div>
</div>
<div class="sect2">
<h3 id="_adding_more_types">Adding More Types</h3>
<div class="paragraph">
<p>If the built-in types don&#8217;t meet your needs, it is easy to register a custom converter. Specify a <code>convert</code> Closure to convert the String argument to any other type. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import java.nio.file.Paths
import java.time.LocalTime
def cli = new CliBuilder()
cli.a(convert: { it.toUpperCase() }, &#39;a-arg&#39;) // (1)
cli.p(convert: { Paths.get(it) }, &#39;p-arg&#39;) // (2)
cli.t(convert: { LocalTime.parse(it) }, &#39;t-arg&#39;) // (3)
def options = cli.parse(&#39;-a abc -p /usr/home -t 15:31:59&#39;.split())
assert options.a == &#39;ABC&#39;
assert options.p.absolute && options.p.parent == Paths.get(&#39;/usr&#39;)
assert options.t.hour == 15 && options.t.minute == 31
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Convert one String to another</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>Option value is converted to a <code>java.nio.file.Path</code></td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>Option value is converted to a <code>java.time.LocalTime</code></td>
</tr>
</table>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_annotations">Annotations</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/a-annotations.png" alt="Annotations">
</div>
</div>
<div class="paragraph">
<p>From this release, Groovy offers an annotation API for processing command line arguments.</p>
</div>
<div class="paragraph">
<p>Applications can annotate fields or methods with <code>@groovy.cli.Option</code> for named options
or <code>@groovy.cli.Unparsed</code> for positional parameters.
When the parser matches a command line argument with an option name or positional parameter, the value is converted
to the correct type and injected into the field or method.</p>
</div>
<div class="sect2">
<h3 id="_annotating_methods_of_an_interface">Annotating Methods of an Interface</h3>
<div class="paragraph">
<p>One way to use the annotations is on &quot;getter-like&quot; methods (methods that return a value) of an interface. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.*
interface IHello {
@Option(shortName=&#39;h&#39;, description=&#39;display usage&#39;) Boolean help() // (1)
@Option(shortName=&#39;u&#39;, description=&#39;user name&#39;) String user() // (2)
@Unparsed(description = &#39;positional parameters&#39;) List remaining() // (3)
}
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Method returns <code>true</code> if <code>-h</code> or <code>--help</code> was specified on the command line.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>Method returns the parameter value that was specified for the <code>-u</code> or <code>--user</code> option.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>Any remaining parameters will be returned as a list from this method.</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>How to use this interface (using the picocli version to demonstrate its usage help):</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.picocli.CliBuilder
def cli = new CliBuilder(name: &#39;groovy Greeter&#39;)
def argz = &#39;--user abc&#39;.split()
IHello hello = cli.parseFromSpec(IHello, argz)
assert hello.user() == &#39;abc&#39;
hello = cli.parseFromSpec(GreeterI, [&#39;--help&#39;, &#39;Some&#39;, &#39;Other&#39;, &#39;Args&#39;] as String[])
assert hello.help()
cli.usage()
assert hello.remaining() == [&#39;Some&#39;, &#39;Other&#39;, &#39;Args&#39;]
</code></pre>
</div>
</div>
<div class="paragraph">
<p>This prints the following usage help message:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code>Usage: groovy Greeter [-h] [-u=&lt;user&gt;] [&lt;remaining&gt;...]
[&lt;remaining&gt;...] positional parameters
-u, --user=&lt;user&gt; user name
-h, --help display usage</code></pre>
</div>
</div>
<div class="paragraph">
<p>When <code>parseFromSpec</code> is called, <code>CliBuilder</code> reads the annotations, parses the command line arguments
and returns an instance of the interface.
The interface methods return the option values matched on the command line.</p>
</div>
</div>
<div class="sect2">
<h3 id="_annotating_properties_or_setter_methods_of_a_class">Annotating Properties or Setter Methods of a Class</h3>
<div class="paragraph">
<p>Another way to use the annotations is on the properties or &quot;setter-like&quot; methods (<code>void</code> methods with a single parameter) of a class. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">class Hello {
@Option(shortName=&#39;h&#39;, description=&#39;display usage&#39;) // (1)
Boolean help
private String user
@Option(shortName=&#39;u&#39;, description=&#39;user name&#39;) // (2)
void setUser(String user) {
this.user = user
}
String getUser() { user }
@Unparsed(description = &#39;positional parameters&#39;) // (3)
List remaining
}
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>The <code>help</code> Boolean property is set to <code>true</code> if <code>-h</code> or <code>--help</code> was specified on the command line.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>The <code>setUser</code> property setter method is invoked with the <code>-u</code> or <code>--user</code> option parameter value.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>The <code>remaining</code> property is set to a new <code>List</code> containing the remaining args, if any.</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>The annotated class can be used as follows:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">String[] argz = [&#39;--user&#39;, &#39;abc&#39;, &#39;foo&#39;]
def cli = new CliBuilder(usage: &#39;groovy Greeter [option]&#39;) // (1)
Hello greeter = cli.parseFromInstance(new Hello(), argz) // (2)
assert greeter.user == &#39;abc&#39; // (3)
assert greeter.remaining == [&#39;foo&#39;] // (4)
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Create a <code>CliBuilder</code> instance.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>Extract options from the annotated instance, parse arguments, and populate and return the supplied instance.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>Verify that the String option value has been assigned to the property.</td>
</tr>
<tr>
<td><i class="conum" value="4"></i><b>4</b></td>
<td>Verify the remaining arguments property.</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>When <code>parseFromInstance</code> is called, <code>CliBuilder</code> again reads the annotations, parses the command line
arguments and finally returns the instance. The annotated fields and setter methods are initialized with the values
matched for the associated option.</p>
</div>
</div>
<div class="sect2">
<h3 id="_script_annotations">Script Annotations</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/GroovyScriptAnnotations.png" alt="Script">
</div>
</div>
<div class="paragraph">
<p>Groovy 2.5 also offers new annotations for Groovy scripts.</p>
</div>
<div class="paragraph">
<p><code>@OptionField</code> is equivalent to combining <code>@groovy.transform.Field</code> and <code>@Option</code>, whereas <code>@UnparsedField</code> is equivalent to combining <code>@Field</code> and <code>@Unparsed</code>.</p>
</div>
<div class="paragraph">
<p>Use these annotations to turn script variables into fields so that the variables can be populated by CliBuilder. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.OptionField
import groovy.cli.UnparsedField
@OptionField String user
@OptionField Boolean help
@UnparsedField List remaining
String[] argz = [&#39;--user&#39;, &#39;abc&#39;, &#39;foo&#39;]
new CliBuilder().parseFromInstance(this, argz)
assert user == &#39;abc&#39;
assert remaining == [&#39;foo&#39;]
</code></pre>
</div>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_typed_positional_parameters">Typed Positional Parameters</h2>
<div class="sectionbody">
<div class="paragraph">
<p>This version of CliBuilder offers some limited support for strongly typed positional parameters.</p>
</div>
<div class="paragraph">
<p>If all positional parameters have the same type, the <code>@Unparsed</code> annotation can be used with an array type other than <code>String[]</code>.
Again, the type conversion is done using <a href="http://docs.groovy-lang.org/2.5.0-SNAPSHOT/html/gapi/index.html?org/codehaus/groovy/runtime/StringGroovyMethods.html#asType">StringGroovyMethods#asType(String, Class)</a>
in the Commons CLI version, while the picocli version of CliBuilder supports a <a href="http://picocli.info/#_built_in_types">superset</a> of those types.</p>
</div>
<div class="paragraph">
<p>This functionality is only available for the annotations API, not for the dynamic API.
Here is an example of an interface that can capture strongly typed positional parameters:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">interface TypedPositionals {
@Unparsed Integer[] nums()
}
</code></pre>
</div>
</div>
<div class="paragraph">
<p>The code below demonstrates the type conversion:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">def argz = &#39;12 34 56&#39;.split()
def cli = new CliBuilder()
def options = cli.parseFromSpec(TypedPositionals, argz)
assert options.nums() == [12, 34, 56]
</code></pre>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_apache_commons_cli_features">Apache Commons CLI Features</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/FeatureIconAdvancedOptions.png" alt="FeatureIconAdvancedOptions">
</div>
</div>
<div class="paragraph">
<p>Sometimes you may want to use advanced features of the underlying parsing library.
For example, you may have a command line application with mutually exclusive options.
The below code shows how to achieve this using the Apache Commons CLI <code>OptionGroup</code> API:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.commons.CliBuilder
import org.apache.commons.cli.*
def cli = new CliBuilder()
def optionGroup = new OptionGroup()
optionGroup.with {
addOption cli.option(&#39;s&#39;, [longOpt: &#39;silent&#39;], &#39;s option&#39;)
addOption cli.option(&#39;v&#39;, [longOpt: &#39;verbose&#39;], &#39;v option&#39;)
}
cli.options.addOptionGroup optionGroup
assert !cli.parse(&#39;--silent --verbose&#39;.split()) (1)
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Parsing this input will fail because two mutually exclusive options were specified.</td>
</tr>
</table>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_picocli_clibuilder_features">Picocli CliBuilder Features</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/FeatureIconAdvancedOptions.png" alt="FeatureIconAdvancedOptions">
</div>
</div>
<div class="sect2">
<h3 id="_strongly_typed_lists">Strongly Typed Lists</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/list.png" alt="list">
</div>
</div>
<div class="paragraph">
<p>Options with multiple values often use an array or a List to capture the values.
Arrays can be strongly typed, that is, contain elements other than String.
The picocli version of CliBuilder lets you do the same with Lists.
The <code>auxiliaryType</code> specifies the type that the elements should be converted to.
For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.picocli.CliBuilder
def cli = new CliBuilder()
cli.T(type: List, auxiliaryTypes: Long, &#39;typed list&#39;) // (1)
def options = cli.parse(&#39;-T 1 -T 2 -T 3&#39;.split()) // (2)
assert options.Ts == [ 1L, 2L, 3L ] // (3)
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Define an option that can have multiple integer values.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>An example command line.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>The option values as a <code>List&lt;Integer&gt;</code>.</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="_strongly_typed_maps">Strongly Typed Maps</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/map.png" alt="map">
</div>
</div>
<div class="paragraph">
<p>The picocli version of CliBuilder offers native support for Map options.
This is as simple as specifying Map as the option type.
By default, both keys and values are stored as Strings in the Map,
but it’s possible to use <code>auxiliaryType</code> to specify the types that the keys and values should be converted to.</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.picocli.CliBuilder
def cli = new CliBuilder()
cli.D(args: 2, valueSeparator: &#39;=&#39;, &#39;Commons CLI style map&#39;) // (1)
cli.X(type: Map, &#39;picocli style map support&#39;) // (2)
cli.Z(type: Map, auxiliaryTypes: [TimeUnit, Integer].toArray(), &#39;typed map&#39;) // (3)
def options = cli.parse(&#39;-Da=b -Dc=d -Xx=y -Xi=j -ZDAYS=2 -ZHOURS=23&#39;.split()) // (4)
assert options.Ds == [&#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;] // (5)
assert options.Xs == [ &#39;x&#39;:&#39;y&#39;, &#39;i&#39;:&#39;j&#39; ] // (6)
assert options.Zs == [ (DAYS as TimeUnit):2, (HOURS as TimeUnit):23 ] // (7)
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Commons CLI has map-like options by specifying that each option must have two parameters, with some separator.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>The picocli version of CliBuilder has native support for Map options.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>The key type and value type can be specified for strongly-typed maps.</td>
</tr>
<tr>
<td><i class="conum" value="4"></i><b>4</b></td>
<td>An example command line.</td>
</tr>
<tr>
<td><i class="conum" value="5"></i><b>5</b></td>
<td>The Commons CLI style option gives a list of [key, value, key, value, &#8230;&#8203;] objects.</td>
</tr>
<tr>
<td><i class="conum" value="6"></i><b>6</b></td>
<td>The picocli style option gives the result as a <code>Map&lt;String, String&gt;</code>.</td>
</tr>
<tr>
<td><i class="conum" value="7"></i><b>7</b></td>
<td>When <code>auxiliaryTypes</code> are specified, the keys and values of the map are converted to the specified types, giving you a <code>Map&lt;TimeUnit, Integer&gt;</code>.</td>
</tr>
</table>
</div>
</div>
<div class="sect2">
<h3 id="_usage_help_with_detailed_synopsis">Usage Help with Detailed Synopsis</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/iceberg.png" alt="iceberg">
</div>
</div>
<div class="paragraph">
<p>CliBuilder has always supported a <code>usage</code> property to display the usage help synopsis of a command:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">// the old way
new CliBuilder(usage: &#39;myapp [options]&#39;).usage()
</code></pre>
</div>
</div>
<div class="paragraph">
<p>The above program prints:</p>
</div>
<div class="listingblock">
<div class="content">
<pre>Usage: myapp [options]</pre>
</div>
</div>
<div class="paragraph">
<p>This still works, but the picocli version has a better alternative with the <code>name</code> property.
If you specify <code>name</code> instead of <code>usage</code>, picocli will show all options in a succinct synopsis with square brackets <code>[</code> and <code>]</code> for optional elements and ellipsis <code>&#8230;&#8203;</code> for elements that can be repeated one or more times. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">// the new way
def cli = new CliBuilder(name: &#39;myapp&#39;) // detailed synopsis
cli.a(&#39;option a description&#39;)
cli.b(&#39;option b description&#39;)
cli.c(type: List, &#39;option c description&#39;)
cli.usage()
</code></pre>
</div>
</div>
<div class="paragraph">
<p>The above program prints:</p>
</div>
<div class="listingblock">
<div class="content">
<pre>Usage: myapp [-ab] [-c=PARAM]...
-a option a description
-b option b description
-c= PARAM option c description</pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_use_any_option_names">Use Any Option Names</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/freedom-c-PsychoShadow-www.bigstockphoto.com.jpg" alt="freedom c PsychoShadow www.bigstockphoto.com">
</div>
</div>
<div class="paragraph">
<p><em>Image credit: (c) PsychoShadow - www.bigstockphoto.com</em></p>
</div>
<div class="paragraph">
<p>Before, if an option had multiple names with a single hyphen, you had no choice but to declare the option multiple times:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">// before: split -cp, -classpath into two options
def cli = new CliBuilder(usage: &#39;groovyConsole [options] [filename]&#39;)
cli.classpath(&#39;Where to find the class files&#39;)
cli.cp(longOpt: &#39;classpath&#39;, &#39;Aliases for &#39;-classpath&#39;)
</code></pre>
</div>
</div>
<div class="paragraph">
<p>The picocli version of CliBuilder supports a <code>names</code> property that can have any number of option names that can take any prefix. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">// after: an option can have many names with any prefix
def cli = new CliBuilder(usage: &#39;groovyConsole [options] [filename]&#39;)
cli._(names: [&#39;-cp&#39;, &#39;-classpath&#39;, &#39;--classpath&#39;], &#39;Where to find the class files&#39;)
</code></pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_fine_grained_usage_help_message">Fine-grained Usage Help Message</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/sift.png" alt="sift">
</div>
</div>
<div class="paragraph">
<p>Picocli offers fine-grained control over the usage help message format and this functionality is exposed via the <code>usageMessage</code> CliBuilder property.</p>
</div>
<div class="paragraph">
<p>The usage message has a number of sections: header, synopsis, description, parameters, options and finally the footer. Each section has a heading, that precedes the first line of its section. For example:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">import groovy.cli.picocli.CliBuilder
def cli = new CliBuilder()
cli.name = &quot;groovy clidemo&quot;
cli.usageMessage.with { // (1)
headerHeading(&quot;Header heading:%n&quot;) // (2)
header(&quot;header 1&quot;, &quot;header 2&quot;) // (3)
synopsisHeading(&quot;%nUSAGE: &quot;)
descriptionHeading(&quot;%nDescription heading:%n&quot;)
description(&quot;description 1&quot;, &quot;description 2&quot;)
optionListHeading(&quot;%nOPTIONS:%n&quot;)
footerHeading(&quot;%nFooter heading:%n&quot;)
footer(&quot;footer 1&quot;, &quot;footer 2&quot;)
}
cli.a(longOpt: &#39;aaa&#39;, &#39;a-arg&#39;) // (4)
cli.b(longOpt: &#39;bbb&#39;, &#39;b-arg&#39;)
cli.usage()
</code></pre>
</div>
</div>
<div class="colist arabic">
<table>
<tr>
<td><i class="conum" value="1"></i><b>1</b></td>
<td>Use the <code>usageMessage</code> CliBuilder property to customize the usage help message.</td>
</tr>
<tr>
<td><i class="conum" value="2"></i><b>2</b></td>
<td>Headings can contain string format specifiers like the <code>%n</code> newline.</td>
</tr>
<tr>
<td><i class="conum" value="3"></i><b>3</b></td>
<td>Sections are multi-line: each string will be rendered on a separate line.</td>
</tr>
<tr>
<td><i class="conum" value="4"></i><b>4</b></td>
<td>Define some options.</td>
</tr>
</table>
</div>
<div class="paragraph">
<p>This prints the following output:</p>
</div>
<div class="listingblock">
<div class="content">
<pre>Header heading:
header 1
header 2
USAGE: groovy clidemo [-ab]
Description heading:
description 1
description 2
OPTIONS:
-a, --aaa a-arg
-b, --bbb b-arg
Footer heading:
footer 1
footer 2</pre>
</div>
</div>
</div>
<div class="sect2">
<h3 id="_usage_help_with_ansi_colors">Usage Help with ANSI Colors</h3>
<div class="paragraph">
<p>Out of the box, the command name, option names and parameter labels in the usage help message are rendered with <a href="http://picocli.info/#_ansi_colors_and_styles">ANSI styles and colors</a>.
The color scheme for these elements can be <a href="http://picocli.info/#_configuring_fixed_elements">configured</a> with system properties.</p>
</div>
<div class="paragraph">
<p>Other than that, you can use colors and styles in the descriptions and other sections of the usage help message,
using a <a href="http://picocli.info/#_usage_help_with_styles_and_colors">simple markup notation</a>. The example below demonstrates:</p>
</div>
<div class="listingblock">
<div class="content">
<pre class="CodeRay highlight"><code lang="groovy">def cli = new groovy.cli.picocli.CliBuilder(name: &#39;myapp&#39;)
cli.usageMessage.with {
headerHeading(&quot;@|bold,red,underline Header heading|@:%n&quot;)
header($/@|bold,green \
___ _ _ ___ _ _ _
/ __| (_) _ )_ _(_) |__| |___ _ _
| (__| | | _ \ || | | / _` / -_) &#39;_|
\___|_|_|___/\_,_|_|_\__,_\___|_|
|@/$)
synopsisHeading(&quot;@|bold,underline Usage|@: &quot;)
descriptionHeading(&quot;%n@|bold,underline Description heading|@:%n&quot;)
description(&quot;Description 1&quot;, &quot;Description 2&quot;) // after the synopsis
optionListHeading(&quot;%n@|bold,underline Options heading|@:%n&quot;)
footerHeading(&quot;%n@|bold,underline Footer heading|@:%n&quot;)
footer($/@|bold,blue \
___ ___ ___
/ __|_ _ ___ _____ ___ _ |_ ) | __|
| (_ | &#39;_/ _ \/ _ \ V / || | / / _|__ \
\___|_| \___/\___/\_/ \_, | /___(_)___/
|__/ |@/$)
}
cli.a(&#39;option a description&#39;)
cli.b(&#39;option b description&#39;)
cli.c(type: List, &#39;option c description&#39;)
cli.usage()
</code></pre>
</div>
</div>
<div class="paragraph">
<p>The code above gives the following output:</p>
</div>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/CliBuilder2.5-cygwin.png" alt="CliBuilder2.5 cygwin">
</div>
</div>
<div class="paragraph">
<p>(Credit to <a href="http://patorjk.com/software/taag/">http://patorjk.com/software/taag/</a> for the ASCII art.)</p>
</div>
</div>
<div class="sect2">
<h3 id="_new_code_errorwriter_code_property">New <code>errorWriter</code> Property</h3>
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/error.png" alt="error">
</div>
</div>
<div class="paragraph">
<p>When the user provided invalid input, the picocli version of CliBuilder writes an error message and the usage help message to the new <code>errorWriter</code> property (set to <code>System.err</code> by default).
When the user requests help, and the application calls <code>CliBuilder.usage()</code>, the usage help message is printed to the <code>writer</code> property (<code>System.out</code> by default).</p>
</div>
<div class="paragraph">
<p>Previous versions of CliBuilder used the <code>writer</code> property for both invalid input and user-requested help.</p>
</div>
<div class="paragraph">
<p>Why this change? This helps command line application authors to follow standard practice and separate diagnostic output from the program output: If the output of a Groovy program is piped to another program,
sending error messages to STDERR prevents the downstream program from inadvertently trying to parse error output.
On the other hand, when users request help with <code>--help</code> or <code>--version</code>, the output should be sent to STDOUT,
because the user may want to pipe the output to a utility like <code>less</code> or <code>grep</code>.</p>
</div>
<div class="paragraph">
<p>For backwards compatibility, setting the <code>writer</code> property to another value will also set the <code>errorWriter</code> to the same value.
(You can still set the <code>errorWriter</code> to another value afterwards if desired.)</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_gotchas_incompatibilities">Gotchas/Incompatibilities</h2>
<div class="sectionbody">
<div class="imageblock">
<div class="content">
<img src="http://picocli.info/images/incompatible.jpg" alt="incompatible">
</div>
</div>
<div class="paragraph">
<p>There are a few areas where the new versions of <code>CliBuilder</code> are not compatible with previous versions or with each other.</p>
</div>
<div class="sect2">
<h3 id="_properties_code_options_code_and_code_formatter_code_unavailable_in_picocli_version">Properties <code>options</code> and <code>formatter</code> Unavailable in Picocli Version</h3>
<div class="paragraph">
<p>The Commons CLI version of CliBuilder, and previous versions of CliBuilder, expose an <code>options</code> property of type <code>org.apache.commons.cli.Options</code>, that can be used to configure the underlying Commons CLI parser without going through the CliBuilder API. This property is not available in the picocli version of CliBuilder.
Applications that read or write this property must import <code>groovy.cli.commons.CliBuilder</code>
or modify the application.</p>
</div>
<div class="paragraph">
<p>Additionally, the <code>formatter</code> property of type <code>org.apache.commons.cli.HelpFormatter</code> is not available in the picocli version of CliBuilder. If your application uses this property, consider using the <code>usageMessage</code> property instead, or import <code>groovy.cli.commons.CliBuilder</code>.</p>
</div>
</div>
<div class="sect2">
<h3 id="_property_code_parser_code_differs_in_picocli_and_commons_cli_versions">Property <code>parser</code> Differs in Picocli and Commons CLI Versions</h3>
<div class="paragraph">
<p>The picocli version of CliBuilder has a <code>parser</code> property that exposes a <code>picocli.CommandLine.Model.ParserSpec</code> object
that can be used to configure the parser behavior.</p>
</div>
<div class="paragraph">
<p>The Commons CLI version of CliBuilder, and previous versions of CliBuilder, expose a <code>parser</code> property of type <code>org.apache.commons.cli.CommandLineParser</code>. This functionality is not available in the picocli version of CliBuilder.</p>
</div>
<div class="paragraph">
<p>If your application uses the <code>parser</code> property to set a different Commons CLI parser, consider using the <code>posix</code> property instead, or import <code>groovy.cli.commons.CliBuilder</code>.</p>
</div>
</div>
<div class="sect2">
<h3 id="_different_parser_behavior_for_code_longoption_code">Different Parser Behavior for <code>longOption</code></h3>
<div class="paragraph">
<p>The Commons CLI <code>DefaultParser</code> recognizes <code>longOption</code> option names prefixed with a single hypen (e.g., <code>-option</code>)
as well as options prefixed with a double hyphen (e.g., <code>--option</code>).
This is not always obvious since the usage help message only shows the double hyphen prefix for <code>longOption</code> option names.</p>
</div>
<div class="paragraph">
<p>For backwards compatibility, the picocli version of CliBuilder has an <code>acceptLongOptionsWithSingleHyphen</code> property:
set this property to <code>true</code> if the parser should recognize long option names with both
a single hyphen and a double hyphen prefix. The default is <code>false</code>,
so only long option names with a double hypen prefix (<code>--option</code>) are recognized.</p>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_conclusion">Conclusion</h2>
<div class="sectionbody">
<div class="paragraph">
<p>Groovy 2.5 CliBuilder offers a host of exciting new features.
Try it out and let us know what you think!</p>
</div>
<div class="paragraph">
<p>For reference: Groovy <a href="http://groovy-lang.org/">site</a> and
GitHub <a href="https://github.com/apache/groovy/">mirror</a>,
picocli <a href="http://picocli.info/">site</a> and
<a href="https://github.com/remkop/picocli">picocli GitHub project</a>.
Please star the projects if you like what you see!</p>
</div>
<div class="paragraph">
<p>A copy of this article was previously published on the picocli website.<br>
<a href="http://picocli.info/groovy-2.5-clibuilder-renewal.html">See the original article here.</a></p>
</div>
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