org.mmbase.util.functions

Class FunctionProvider

java.lang.Object

org.mmbase.util.functions.FunctionProvider

Direct Known Subclasses:

BeanFunctionProvider, ClassFunctionProvider, DescribedFunctionProvider, FunctionSet, IndexFunction, MMTable, PatternNodeFunctionProvider

public abstract class FunctionProvider
extends Object

A function provider maintains a set of Function objects.

Since:

MMBase-1.8

Version:

$Id$

Author:

Pierre van Rooden

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<String,Function<?>>	functions
protected Function<Collection<Function<?>>>	getFunctions Every Function Provider provides least the 'getFunctions' function, which returns a Set of all functions which it provides.

Constructor Summary

Constructors

Constructor and Description
FunctionProvider() The constructor of an FunctionProvider guesses the functions using reflection.

Method Summary

Modifier and Type	Method and Description
Function<?>	addFunction(Function<?> function) Adds a function to the FunctionProvider.
Parameters	createParameters(String functionName) Creates a new empty Parameters object for given function.
Function<?>	getFunction(String functionName) Returns the Function object with given name.
Collection<Function<?>>	getFunctions() Returns a Collection of all functions currently provided by the FunctionProvider.
Object	getFunctionValue(String functionName, List<?> parameters) Executes a function, and returns the function value.
protected Function<?>	newFunctionInstance(String name, Parameter<?>[] parameters, ReturnType returnType)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

functions

protected Map<String,Function<?>> functions

getFunctions

protected Function<Collection<Function<?>>> getFunctions

Every Function Provider provides least the 'getFunctions' function, which returns a Set of all functions which it provides.

Constructor Detail

FunctionProvider

public FunctionProvider()

The constructor of an FunctionProvider guesses the functions using reflection.

To Do:

Should this last thing not only be done on MMObjectBuilders?

Method Detail

newFunctionInstance

protected Function<?> newFunctionInstance(String name,
                                          Parameter<?>[] parameters,
                                          ReturnType returnType)

addFunction

public Function<?> addFunction(Function<?> function)

Adds a function to the FunctionProvider. So, you can implement any function and add it to the provider, to make it provide this function too.

Returns:

The function previously assigned with this name or null if no such function.

createParameters

public Parameters createParameters(String functionName)

Creates a new empty Parameters object for given function.

Returns:

A new empty Parameters object, or null if no such function.

getFunctionValue

public Object getFunctionValue(String functionName,
                               List<?> parameters)

Executes a function, and returns the function value.

Returns:

The function value or null if no such function.

getFunction

public Function<?> getFunction(String functionName)

Returns the Function object with given name.

Returns:

Function object or null if no such function is provided.

getFunctions

public Collection<Function<?>> getFunctions()

Returns a Collection of all functions currently provided by the FunctionProvider.