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 in) is passed to the
VariableInterpolator 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").
author: Jonathan Locke |