implements ExpressionManager, Component, Configurable, ThreadSafe {
private DefaultFunctionFactory factory;
public void configure(Configuration config) throws ConfigurationException {
factory = new DefaultFunctionFactory();
Configuration[] functions = config.getChildren("function");
for (int i = 0; i < functions.length; i++) {
String name = functions[i].getAttribute("name");
String clazz = functions[i].getAttribute("class");