org.mmbase.util.functions
Class FunctionProvider

java.lang.Object
  org.mmbase.util.functions.FunctionProvider

Direct Known Subclasses:

BeanFunctionProvider, ClassFunctionProvider, DescribedFunctionProvider, FunctionSet, PatternNodeFunctionProvider

public abstract class FunctionProvider
extends Object

A function provider maintains a set of Function objects.

Since:

MMBase-1.8

Version:

$Id: FunctionProvider.java 45226 2011-02-16 11:00:25Z michiel $

Author:

Pierre van Rooden

Field Summary

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

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

Method Summary

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?, Calling an overridable method ({@link #newFunctionInstance(java.lang.String, org.mmbase.util.functions.Parameter[], org.mmbase.util.functions.ReturnType) ). This is generally ill adviced.

Method Detail

newFunctionInstance

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

addFunction

public final 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.