Package org.ow2.authzforce.core.pdp.api.func

Class BaseFirstOrderFunctionCall<RETURN extends Value>

java.lang.Object

org.ow2.authzforce.core.pdp.api.func.BaseFirstOrderFunctionCall<RETURN>

Type Parameters:

RETURN - function return type

All Implemented Interfaces:

FirstOrderFunctionCall<RETURN>, FunctionCall<RETURN>

Direct Known Subclasses:

BaseFirstOrderFunctionCall.EagerEval

public abstract class BaseFirstOrderFunctionCall<RETURN extends Value>
extends Object
implements FirstOrderFunctionCall<RETURN>

This class provides a skeletal implementation of the FirstOrderFunctionCall interface, to minimize the effort required to implement this interface. It requires a function definition and given arguments to be passed to the function, and based on this information, enforces type checking. It is the recommended way of calling any FirstOrderFunction instance.

Some of the arguments (expressions) may not be known in advance, but only at evaluation time (when calling evaluate(EvaluationContext, boolean, AttributeValue...)). For example, when using a FirstOrderFunction as a sub-function of the Higher-Order function 'any-of', the last arguments of the sub-function are determined during evaluation, after evaluating the expression of the last input in the context, and getting the various values in the result bag.

In the case of such evaluation-time args, you must pass their types (the datatype of the last input bag in the previous example) as the remainingArgTypes parameters to the BaseFirstOrderFunctionCall subclass (e.g. BaseFirstOrderFunctionCall.EagerEval implementation) constructor, and correspond to the types of the remainingArgs passed later as parameters to evaluate(EvaluationContext, boolean, AttributeValue...).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	BaseFirstOrderFunctionCall.EagerBagEval<RETURN_T extends Value,PARAM_BAG_ELEMENT_T extends AttributeValue>	Function call, for functions requiring eager (a.k.a.
static class	BaseFirstOrderFunctionCall.EagerEval<RETURN_T extends Value>	Function call, for FirstOrderFunctions requiring eager (aka greedy) evaluation of ALL their arguments' expressions to actual values, before the function can be evaluated.
static class	BaseFirstOrderFunctionCall.EagerMultiPrimitiveTypeEval<RETURN_T extends Value>	Function call, for functions requiring eager (a.k.a.
static class	BaseFirstOrderFunctionCall.EagerPartlyBagEval<RETURN_T extends Value,PRIMITIVE_PARAM_T extends AttributeValue>	Function call, for functions requiring eager (a.k.a.
static class	BaseFirstOrderFunctionCall.EagerSinglePrimitiveTypeEval<RETURN_T extends Value,PARAM_T extends AttributeValue>	Function call, for functions requiring eager (a.k.a.

Constructor Summary

Constructors

Constructor	Description
BaseFirstOrderFunctionCall(FirstOrderFunctionSignature<RETURN> functionSig, List<Expression<?>> argExpressions, Datatype<?>... remainingArgTypes)	Instantiates a function call, including the validation of arguments (inputExpressions ) according to the function definition.

Method Summary

Modifier and Type	Method	Description
RETURN	evaluate(EvaluationContext context)	Make the call in a given evaluation context
RETURN	evaluate(EvaluationContext context, boolean checkRemainingArgTypes, AttributeValue... remainingArgs)	Make the call in a given evaluation context.
Datatype<RETURN>	getReturnType()	Get the actual return type of this call (same as the internal function's return type), used as return type for XACML Apply in PDP.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.ow2.authzforce.core.pdp.api.func.FirstOrderFunctionCall

evaluate

Constructor Detail

BaseFirstOrderFunctionCall

public BaseFirstOrderFunctionCall(FirstOrderFunctionSignature<RETURN> functionSig,
                                  List<Expression<?>> argExpressions,
                                  Datatype<?>... remainingArgTypes)
                           throws IllegalArgumentException

Instantiates a function call, including the validation of arguments (inputExpressions ) according to the function definition.

Parameters:

functionSig - signature of function to which this call applies

argExpressions - function arguments (expressions)

remainingArgTypes - types of arguments of which the actual Expressions are unknown at this point, but will be known and passed at evaluation time as remainingArgs parameter to evaluate(EvaluationContext, boolean, AttributeValue...), then FirstOrderFunctionCall.evaluate(EvaluationContext, AttributeValue...). Only non-bag/primitive values are valid remainingArgs to prevent varargs warning in FirstOrderFunctionCall.evaluate(EvaluationContext, AttributeValue...) (potential heap pollution via varargs parameter) that would be caused by using a parameterized type such as Value/Collection to represent both bags and primitives.

Throws:

IllegalArgumentException - if inputs are invalid for this function or one of remainingArgTypes is a bag type.

Method Detail

evaluate

public final RETURN evaluate(EvaluationContext context)
                      throws IndeterminateEvaluationException

Description copied from interface: FunctionCall

Make the call in a given evaluation context

Specified by:

evaluate in interface FunctionCall<RETURN extends Value>

Parameters:

context - evaluation context

Returns:

result of the call

Throws:

IndeterminateEvaluationException - if any evaluation error

evaluate

public final RETURN evaluate(EvaluationContext context,
                             boolean checkRemainingArgTypes,
                             AttributeValue... remainingArgs)
                      throws IndeterminateEvaluationException

Description copied from interface: FirstOrderFunctionCall

Make the call in a given evaluation context. This method calls the function after checking remainingArgTypes if checkremainingArgTypes = true

Specified by:

evaluate in interface FirstOrderFunctionCall<RETURN extends Value>

Parameters:

context - evaluation context

checkRemainingArgTypes - whether to check types of remainingArgs. It is strongly recommended to set this to true always, unless you have already checked the types are OK before calling this method and want to skip re-checking for efficiency.

remainingArgs - remaining args.

Returns:

result of the call

Throws:

IndeterminateEvaluationException - if checkremainingArgTypes = true and remainingArgs do not check OK, or if they do but there was an error evaluating the function with such arguments

getReturnType

public final Datatype<RETURN> getReturnType()

Description copied from interface: FunctionCall

Get the actual return type of this call (same as the internal function's return type), used as return type for XACML Apply in PDP.

Specified by:

getReturnType in interface FunctionCall<RETURN extends Value>

Returns:

return type