org.apache.juneau.svl.vars.IfVar Maven / Gradle / Ivy
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package org.apache.juneau.svl.vars;
import static org.apache.juneau.internal.ThrowableUtils.*;
import org.apache.juneau.svl.*;
/**
* A basic if-else logic variable resolver.
*
*
* The format for this var is one of the following:
*
* "$IF{booleanArg,thenValue}"
* "$IF{booleanArg,thenValue,elseValue}"
*
*
*
* The boolean argument is any string.
*
The following values are interpreted as true : "true" ,"TRUE" ,"t" ,
* "T" ,"1" .
*
All else are interpreted as false
*
*
Example:
*
* // Create a variable resolver that resolves system properties and $IF vars.
* VarResolver r = VarResolver.create ().vars(IfVar.class , SystemPropertiesVar.class ).build();
*
* // Use it!
* System.out .println(r.resolve("Property $IF{$S{someBooleanFlag},IS,IS NOT} set!" ));
*
*
*
* Since this is a {@link MultipartVar}, any variables contained in the result will be recursively resolved.
*
Likewise, if the arguments contain any variables, those will be resolved before they are passed to this var.
*
*
See Also:
*
* - {@doc juneau-svl.SvlVariables}
*
*/
public class IfVar extends MultipartVar {
/** The name of this variable. */
public static final String NAME = "IF";
/**
* Constructor.
*/
public IfVar() {
super(NAME);
}
@Override /* MultipartVar */
public String resolve(VarResolverSession session, String[] args) {
if (args.length < 2 || args.length > 3)
illegalArg("Invalid number of arguments passed to $IF var. Must be either $IF{booleanArg,thenValue} or $IF{booleanArg,thenValue,elseValue}");
String b = args[0].toLowerCase();
if ("1".equals(b) || "t".equals(b) || "true".equals(b))
return args[1];
return args.length == 2 ? "" : args[2];
}
}