juneau-doc/docs/Topics/11.juneau-microservice-core/03.Args.html

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Args

<p>
	Command-line arguments can be associated with a microservice using the {@link oaj.microservice.MicroserviceBuilder#args(String...)} method.
</p>
<h5 class='figure'>Example:</h5>
<p class='bpcode w800'>
	<jk>public static void</jk> main(String[] args) {
		Microservice
			.<jsm>create</jsm>()          <jc>// Create builder.</jc>
			.args(args)        <jc>// Pass in args.</jc>
			.build()           <jc>// Create microservice.</jc>
			.start()           <jc>// Start microservice.</jc>
			.join()            <jc>// Join thread.</jc>
		;
	}
</p>
<p>
	When specified, the arguments can be retrieved using the {@link oaj.microservice.Microservice#getArgs()} method which provides
	an API for easily accessing command-line arguments using common notation:
</p>
<p class='bpcode w800'>
	Args a = Microservice.<jsm>getInstance</jsm>().getArgs();
	
	<jc>// One main argument</jc>
	<jc>// a1</jc>
	String a1 = a.getArg(0); <jc>// "a1"</jc>
	String a2 = a.getArg(1); <jc>// null</jc>

	<jc>// Two main arguments</jc>
	<jc>// a1 a2</jc>
	String a1 = a.getArg(0); <jc>// "a1"</jc>
	String a2 = a.getArg(1); <jc>// "a2"</jc>

	<jc>// One main argument and one optional argument with no value</jc>
	<jc>// a1 -a2</jc>
	String a1 = a.getArg(0);
	<jk>boolean</jk> hasA2 = a.hasArg(<js>"a2"</js>); <jc>// true</jc>
	<jk>boolean</jk> hasA3 = a.hasArg(<js>"a3"</js>); <jc>// false</jc>

	<jc>// One main argument and one optional argument with one value</jc>
	<jc>// a1 -a2 v2</jc>
	String a1 = a.getArg(0);
	String a2 = a.getArg(<js>"a2"</js>); <jc>// "v2"</jc>
	String a3 = a.getArg(<js>"a3"</js>); <jc>// null</jc>

	<jc>// One main argument and one optional argument with two values</jc>
	<jc>// a1 -a2 v2a v2b</jc>
	String a1 = a.getArg(0);
	List&lt;String&gt; a2 = a.getArgs(<js>"a2"</js>); <jc>// Contains ["v2a","v2b"]</jc>
	List&lt;String&gt; a3 = a.getArgs(<js>"a3"</js>); <jc>// Empty list</jc>

	<jc>// Same as previous, except specify optional argument name multiple times</jc>
	<jc>// a1 -a2 v2a -a2 v2b</jc>
	String a1 = a.getArg(0);
	List&lt;String&gt; a2 = a.getArgs(<js>"a2"</js>); <jc>// Contains ["v2a","v2b"]</jc>
</p>
<p>
	Specifying the command-line arguments also makes them available through {@link oaj.svl.vars.ArgsVar $A} SVL variables.
	These can be used in the configuration file and throughout various Juneau annotations.
</p>
<h5 class='figure'>Example:</h5>
<p class='bpcode w800'>
	<jc>// $A used in variable resolver.</jc>
	VarResolver vr = Microservice.<jsm>getInstance</jsm>().getVarResolver();
 	System.<jsf>out</jsf>.println(vr.resolve(<js>"Arg #1 is set to $A{1}"</js>));
</p>
<p class='bpcode w800'>
	<jc>// $A used in annotation.</jc>
	<ja>@Rest</ja>(
		title=<js>"$A{title}"</js>,
		...
	)
</p>