net.sf.basedb.util.jep
Interface JepExpressionFunction

All Superinterfaces:

JepFunction, org.nfunk.jep.function.PostfixMathCommandI

All Known Implementing Classes:

ChannelFunction, ExtraValueFunction, Log2Function, MeanFunction, PositionFunction, RawChannelFunction, RawFunction, ReporterFunction, ScoreFunction

public interface JepExpressionFunction
extends JepFunction

This interface should be implemented by JEP functions that can also be converted into an Expression that can be used in queries.

Version:

2.0

Author:

Nicklas

See Also:

Jep.formulaToExpression(String, JepFunction[])

Last modified

$Date: 2009-04-06 14:52:39 +0200 (Mon, 06 Apr 2009) $

Method Summary

Expression

toExpression(Node node) Convert this function to an Expression that can be used in a query.

Methods inherited from interface net.sf.basedb.util.jep.JepFunction

getFunctionName

Methods inherited from interface org.nfunk.jep.function.PostfixMathCommandI

checkNumberOfParameters, getNumberOfParameters, run, setCurNumberOfParameters

Method Detail

toExpression

Expression toExpression(Node node)

Convert this function to an Expression that can be used in a query. The implementation must check that the node contains the correct number of children (ie. arguments to the function) and convert the arguments to whatever is suitable for the expression. Example from the Log2Function

int numChildren = node.jjtGetNumChildren();
if (numChildren != 1)
{
   throw new BaseException("Invalid number of arguments for 'log2' function: " + numChildren);
}
return Expressions.log2(Jep.nodeToExpression(node.jjtGetChild(0)));

Parameters:

node - The node representing this function

Returns:

An Expression object