Transformation Guide

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invokeJExpression

Invokes an expression and returns the value for the expression.

Use the following syntax:

(datatype)invokeJExpression(
                      String expression, 
                      Object[] paramMetadataArray);

Input parameters for the invokeJExpression method are a string value that represents the expression and an array of objects that contain the expression input parameters.

The following table describes the parameters:

Parameter	Parameter Type	Datatype	Description
expression	Input	String	String that represents the expression.
paramMetadataArray	Input	Object[]	Array of objects that contain the input parameters for the expression.

You can add the invokeJExpression method to the Java code on any code entry tab except the

Imports

and

Functions

Import Packages

and

Java Expressions

tabs.

Use the following rules and guidelines when you use the invokeJExpression method:

Return datatype. The return datatype of the invokeJExpression method is an object. You must cast the return value of the function with the appropriate datatype.

You can return values with Integer, Double, String, and byte[] datatypes.

Row type. The row type for return values from the invokeJExpression method is INSERT.

To use a different row type for the return value, use the advanced interface.

Null values. If you pass a null value as a parameter or the return value for the invokeJExpression method is NULL, the value is treated as a null indicator.

For example, if the return value of an expression is NULL and the return datatype is String, a string is returned with a value of null.

Date datatype. You must convert input parameters with a Date datatype to the String datatype.

To use the string in an expression as a Date datatype, use the to_date() function to convert the string to a Date datatype.

Also, you must cast the return type of any expression that returns a Date datatype as a String datatype.

The following example concatenates the strings “John” and “Smith” and returns the string, “John Smith”:

(String)invokeJExpression("concat(x1,x2)", new Object [] { "John ", "Smith" });

You must number the parameters that you pass to the expression consecutively, and start the parameter with the letter x. For example, to pass three parameters to an expression, name the parameters x1, x2, and x3.

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Transformation Guide

Transformation Guide

invokeJExpression

invokeJExpression