juneau-doc/docs/Topics/11.juneau-microservice-core/07.VarResolver.html

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{8.0.0-new, 8.1.2-deprecated} 
VarResolver

<p>
	The Microservice API incorporates the {@doc juneau-marshall.SimpleVariableLanguage Simple Variable Language} API.
</p>
<p>
	The variable resolver can be augmented through the following methods:
</p>
<ul class='javatree'>
	<li class='jc'>{@link oaj.microservice.MicroserviceBuilder}
	<ul>
		<li class='jm'>{@link oaj.microservice.MicroserviceBuilder#vars(Class...) vars(Class...)} 
		<li class='jm'>{@link oaj.microservice.MicroserviceBuilder#varContext(String, Object) varContext(String,Object)} 
	</ul>
</ul>
<p>
	A typical usage pattern is shown below:
</p>
<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>"Main class is set to $MF{Main-Class, unknown}"</js>));
</p>
<p>
	The variable resolver becomes much more powerful when used in REST resource annotations which will be
	described latter in {@doc juneau-microservice-jetty}
</p>
<p>
	By default, support for the following variables are provided:
</p>
<ul>
	<li><c>$S{key[,default]}</c> - {@link oaj.svl.vars.SystemPropertiesVar}
	<li><c>$E{key[,default]}</c> - {@link oaj.svl.vars.EnvVariablesVar}
	<li><c>$A{key[,default]}</c> - {@link oaj.svl.vars.ArgsVar}
	<li><c>$C{key[,default]}</c> - {@link oaj.config.vars.ConfigVar}
	<li><c>$MF{key[,default]}</c> - {@link oaj.svl.vars.ManifestFileVar}
	<li><c>$IF{arg,then[,else]}</c> - {@link oaj.svl.vars.IfVar}
	<li><c>$SW{arg,pattern1:then1[,pattern2:then2...]}</c> - {@link oaj.svl.vars.SwitchVar}
	<li><c>$CO{arg[,arg2...]}</c> - {@link oaj.svl.vars.CoalesceVar}
	<li><c>$PM{arg,pattern}</c> - {@link oaj.svl.vars.PatternMatchVar}
	<li><c>$UC{arg}</c> - {@link oaj.svl.vars.UpperCaseVar}
	<li><c>$LC{arg}</c> - {@link oaj.svl.vars.LowerCaseVar}
	<li><c>$NE{arg}</c> - {@link oaj.svl.vars.NotEmptyVar}
</ul>