code: public String getExpressionString() {
          StringBuffer b = new StringBuffer();
          b.append(functionName);
          b.append("(");
          Iterator i = argumentList.iterator();
          while (i.hasNext()) {
              b.append(((Expression) i.next()).getExpressionString());
              if (i.hasNext()) {
                  b.append(", ");
              }
          }
          b.append(")");
          return b.toString();
      }
docs: Returns the expression in the expression language syntax