Base class for variable interpolators. An interpolator substitutes values into a
String
. So, a variable interpolator substitutes the values of one or more variables into a
String
.
The String
to interpolate (substitute into) is passed to the VariableInterpolator
's constructor. Variables are denoted in this string by the syntax ${variableName}
. A subclass provides an implementation for the abstract method getValue(String variableName)
. The toString()
method then performs an interpolation by replacing each variable of the form ${variableName}
with the value returned by getValue("variableName")
.
"$" is the escape char. Thus "$${text}" can be used to escape it (ignore interpretation). If '$3.24' is needed then '$$${amount}' should be used. The first $ sign escapes the second, and the third is used to interpolate the variable.
@author Jonathan Locke
@since 1.2.6