Parameter style JAVA Java functions and methods

The signature of PARAMETER STYLE JAVA functions and methods follows this format:

public static return-type method-name ( SQL-arguments ) throws SQLException

return-type

The data type of the value to be returned by the scalar routine. Inside the routine, the return value is passed back to the invoker through a return statement.

method-name

Name of the method. During routine registration, this value is specified with the class name in the EXTERNAL NAME clause of the routine's CREATE statement.

SQL-arguments

Corresponds to the list of input parameters in the routine's CREATE statement.

The following is an example of a Java function that returns the product of its two input arguments:

public static double product( double in1, double in2 ) throws SQLException
{
  return in1 * in2;
}

The corresponding CREATE FUNCTION statement for this scalar function is as follows:

CREATE FUNCTION product( in1 DOUBLE, in2 DOUBLE )
  RETURNS DOUBLE
  LANGUAGE java
  PARAMETER STYLE java
  NO SQL 
  FENCED THREADSAFE
  DETERMINISTIC 
  RETURNS NULL ON NULL INPUT
  NO EXTERNAL ACTION
  EXTERNAL NAME 'myjar:udfclass.product'

The preceding statement assumes that the method is in a class called udfclass that is located in a JAR file that has been installed to the database server with the Jar ID myjar. JAR files can be installed to a database server using the INSTALL_JAR built-in procedure.