org.apache.commons.digester.substitution

The class org.apache.commons.digester.Substitutor defines an abstract interface for mechanisms which manipulate xml attributes and body text. The Digester method setSubstitutor can be used to define a concrete substitutor that will be applied to the data before it is passed to the matching rules.

This package provides some useful concrete implementations of the abstract Substitutor class. In particular, it provides an implementation that allows the application to define "variables" which the input data can reference using a syntax such as "${user.name}".

Here's an example of setting up the VariableSubstitutor:

  // set up the variables the input xml can reference
  Map vars = new HashMap();
  vars.put("user.name", "me");
  vars.put("os", "Linux");
  
  // map ${varname} to the entries in the var map
  MultiVariableExpander expander = new MultiVariableExpander();
  expander.addSource("$", vars);

  // allow expansion in both xml attributes and element text
  Substitutor substitutor = new VariableSubstitutor(expander);

  Digester digester = new Digester();
  digester.setSubstitutor(substitutor);

Wrapper for an org.xml.sax.Attributes object which expands any "variables" referenced in the attribute value via ${foo} or similar.

An Interface describing a class capable of expanding strings which may contain variable references.

Test Case for the variable expansion facility in Digester.