org.axiondb.functions
Class SubstringFunction
java.lang.Object
org.axiondb.BaseSelectable
org.axiondb.functions.BaseFunction
org.axiondb.functions.SubstringFunction
- All Implemented Interfaces:
- ConcreteFunction, Function, FunctionFactory, ScalarFunction, Selectable, Serializable
- public class SubstringFunction
- extends BaseFunction
- implements ScalarFunction, FunctionFactory
Syntax: SUBSTRING(str, m [,n]) -- m is one(1) based index.)
- Version:
- $Revision: 1.4 $ $Date: 2004/09/09 23:47:44 $
- See Also:
- Serialized Form
Methods inherited from class org.axiondb.functions.BaseFunction |
addArgument, getAlias, getArgument, getArgumentCount, getLabel, getName, setAlias, setArgument, setName, setVariableContext, toString |
SubstringFunction
public SubstringFunction()
- Creates a new instance of Class
makeNewInstance
public ConcreteFunction makeNewInstance()
- Specified by:
makeNewInstance
in interface FunctionFactory
getDataType
public DataType getDataType()
StringType
- Specified by:
getDataType
in interface Selectable
- Specified by:
getDataType
in class BaseFunction
evaluate
public Object evaluate(RowDecorator row)
throws AxionException
- Returns substring of str, beginning at character m, n characters long. If
m is 0, it is treated as 1. If m is positive, it counts from the beginning of str
to find the first character. If m is negative, it counts backwards from the end of
str. If n is omitted, it returns all characters to the end of str. If n is less
than 1, a null is returned. Floating-point numbers passed as arguments to substr
are automatically converted to integers. If m greater than length of str, return
null. If m+n is bigger than length of str, ignore n. if str is null, return null.
- Specified by:
evaluate
in interface ScalarFunction
- Throws:
AxionException
isValid
public boolean isValid()
- Specified by:
isValid
in interface ConcreteFunction
- Specified by:
isValid
in class BaseFunction