code: public String getExpressionString() {
          StringBuffer buf = new StringBuffer();
          for (int i = 0; i < mElements.length; i++) {
              Object elem = mElements[i];
              if (elem instanceof String) {
                  buf.append((String) elem);
              } else if (elem instanceof Expression) {
                  buf.append("${");
                  buf.append(((Expression) elem).getExpressionString());
                  buf.append("}");
              }
          }
          return buf.toString();
      }
docs: Returns the expression in the expression language syntax