org.faktorips.runtime

Interface TableFunctionExecution

public interface TableFunctionExecution

This interface is used for code that is generated for table access functions called within the formula language. Since the fl-language is an expression language the java code that is generated is also an expression. A problem arises when a call to a table within the generated java expression returns null instead of a table row. Since this causes a NullPointerException when a getter-method is called upon the row instance special care has to be taken to circumvent this situation. Therefor a table function call within the formula language is generated as java code within the execute method of an anonymous class of this interface. Within the execute method the null situation can be handled within an if block. Example:

public Decimal computePremium(final Integer age) { return ((Decimal)(new TableFunctionExecution() { public Object execute() { TableWithMultipleContentsRow row = TableWithMultipleContents.getInstance(getRepository(), "tables.TableWithMultipleContents1").findRow(age); if (row != null) { return row.getRate(); } return Decimal.NULL; } }).execute()); }

Author:

Peter Erzberger

Method Summary

Methods

Modifier and Type	Method and Description
Object	execute() Executes the java code that is generated for a table function call of the formula language.

Method Detail

execute

Object execute()

Executes the java code that is generated for a table function call of the formula language.

Returns:

the return value of the function or null or a null special case value if if the no row was found in the table for the parameters that have been provided to the table function.