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java.lang.Objectorg.outerj.expression.AbstractExpression
org.outerj.grouping.functions.ColumnFunction
Function for usage in Expression's that returns the value of a certain column on the current row in a Table. This function should only be used inside summary functions, like SSum, otherwise the "current row" will not be defined and may give errors or unexpected results.
Note: the expression library work internally only with BigDecimal's to represent numbers. This function supposes the Table only contains BigDecimal or Long values. Long values will be automatically converted to BigDecimal ones.
Field Summary |
Fields inherited from class org.outerj.expression.AbstractExpression |
arguments, column, line |
Constructor Summary | |
ColumnFunction()
|
Method Summary | |
void |
check()
Check if the expression's structure is OK. |
java.lang.Object |
evaluate(ExpressionContext context)
Evaluates this expression and returns the result of that evaluation. |
java.lang.String |
getDescription()
Returns a description of this expression that will be shown to the user in error messages. |
java.lang.Class |
getResultType()
Returns the class of the the type of object that this expression will return. |
Methods inherited from class org.outerj.expression.AbstractExpression |
addArgument, addArgument, checkArgument, checkArguments, checkArgumentsOfSameType, checkNoArguments, getColumn, getLine, setPosition |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Constructor Detail |
public ColumnFunction()
Method Detail |
public java.lang.Object evaluate(ExpressionContext context) throws ExpressionException
Expression
ExpressionException
public java.lang.Class getResultType()
Expression
null
.
public void check() throws ExpressionException
Expression
check
in interface Expression
check
in class AbstractExpression
ExpressionException
public java.lang.String getDescription()
Expression
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