All Known Implementing Classes:

AbsFunction, BodyStartFunction, FromNearestSpecifiedValueFunction, FromParentFunction, FromTableColumnFunction, FunctionBase, InheritedPropFunction, LabelEndFunction, MaxFunction, MinFunction, OCAColorFunction, ProportionalColumnWidthFunction
```
public interface Function
```
Interface for managing XSL-FO Functions

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`Property`	`eval(Property[] args, PropertyInfo pi)`	Evaluate the function
`Property`	`getOptionalArgDefault(int index, PropertyInfo pi)`
`int`	`getOptionalArgsCount()`
`PercentBase`	`getPercentBase()`
`int`	`getRequiredArgsCount()`
`boolean`	`hasVariableArgs()`	Determine if function allows variable arguments.

- Method Detail
  - getRequiredArgsCount
```
int getRequiredArgsCount()
```
    Returns:
    
    the number of required (non-optional) arguments that must be specified in the argument list
  - getOptionalArgsCount
```
int getOptionalArgsCount()
```
    Returns:
    
    the number of non-required (optional) arguments that may be specified in the argument list, which, if specified, must follow the required arguments
  - getOptionalArgDefault
```
Property getOptionalArgDefault(int index,
                               PropertyInfo pi)
                        throws PropertyException
```
    Parameters:
    
    index - of optional argument
    
    pi - property information instance that applies to property being evaluated
    
    Returns:
    
    the default property value for the optional argument at INDEX, where INDEX is with respect to optional arguments; i.e., the first optional argument position is index 0; if no default for a given index, then null is returned
    
    Throws:
    
    PropertyException - if index is greater than or equal to optional args count
  - hasVariableArgs
```
boolean hasVariableArgs()
```
    Determine if function allows variable arguments. If it does, then they must appear after required and optional arguments, and all optional arguments must be specified.
    
    Returns:
    
    true if function permits additional variable number of arguments after required and (completely specified) optional arguments
  - getPercentBase
```
PercentBase getPercentBase()
```
    Returns:
    
    the basis for percentage calculations
  - eval
```
Property eval(Property[] args,
              PropertyInfo pi)
       throws PropertyException
```
    Evaluate the function
    
    Parameters:
    
    args - an array of Properties that should be evaluated
    
    pi - property information instance that applies to property being evaluated
    
    Returns:
    
    the Property satisfying the function
    
    Throws:
    
    PropertyException - for problems when evaluating the function

Interface Function

Method Summary

Method Detail

getRequiredArgsCount

getOptionalArgsCount

getOptionalArgDefault

hasVariableArgs

getPercentBase

eval