SVL Variables

Variables are defined through the Var API. The API comes with several predefined variables and is easily extensible.

The following is an example of a variable that performs URL-Encoding on strings.

// First create our var.
public class UrlEncodeVar extends SimpleVar {

    // Must have a no-arg constructor!
    public UrlEncodeVar() {
        super("UE");
    }

    // The method we must implement
    @Override
    public String resolve(VarResolverSession session, String key) {
        return URLEncoder.encode(key, "UTF-8");
    }
}

// Next create a var resolver that extends the existing DEFAULT resolver
// that supports resolving system properties.
VarResolver varResolver = VarResolver.DEFAULT
    .copy()
    .vars(UrlEncodeVar.class)
    .build();

// Retrieve a system property and URL-encode it if necessary.
String myProperty = varResolver.resolve("$UE{$S{my.property}}");

The following shows the class hierarchy of the Var class:

Var - Superclass of all vars.SimpleVar - Superclass of all vars that return strings.DefaultingVar - Variables that define a default value if the resolve method returns null.MapVar - Variables that pull values from maps.MultipartVar - Variables that consist of 2 or more comma-delimited arguments.StreamedVar - Superclass of all vars that stream their value to writers.

The following is the list of default variables defined in all modules:

Module	Class	Pattern
juneau-svl	EnvVariablesVar	$E{key[,default]}
	SystemPropertiesVar	$S{key[,default]}
	ArgsVar	$A{key[,default]}
	ManifestFileVar	$MF{key[,default]}
	IfVar	$IF{arg,then[,else]}
	SwitchVar	$SW{arg,pattern1:then1[,pattern2:then2...]}
	CoalesceVar	$CO{arg1[,arg2...]}
	PatternMatchVar	$PM{arg,pattern}
	PatternReplaceVar	$PR{arg,pattern,replace}
	PatternExtractVar	$PE{arg,pattern,groupdIndex}
	NotEmptyVar	$NE{arg}
	UpperCaseVar	$UC{arg}
	LowerCaseVar	$LC{arg}
	LenVar	$LN{arg[,delimiter]}
	SubstringVar	$ST{arg,start[,end]}
	HtmlWidgetVar	$W{name}
juneau-config	ConfigVar	$C{key[,default]}
juneau-rest-server	FileVar	$F{path[,default]}
	ServletInitParamVar	$I{name[,default]}
	LocalizationVar	$L{key[,args...]}
	RequestAttributeVar	$RA{key1[,key2...]}
	RequestFormDataVar	$RF{key1[,key2...]}
	RequestHeaderVar	$RH{key1[,key2...]}
	RequestPathVar	$RP{key1[,key2...]}
	RequestQueryVar	$RQ{key1[,key2...]}
	RequestSwaggerVar	$RS{key}
	RequestVar	$R{key1[,key2...]}
	SerializedRequestAttrVar	$SA{contentType,key[,default]}
	SwaggerVar	$SS{key1[,key2...]}
	UrlVar	$U{uri}
	UrlEncodeVar	$UE{uriPart}