TAO_CosTrader  2.0.8
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TAO_Constraint_Evaluator Class Reference

TAO_Constraint_Evaluator traverse a constraint expression tree, and determines whether an offer fits the constraints represented by the tree. More...

#include <Constraint_Visitors.h>

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List of all members.

Classes

class  Operand_Queue

Public Member Functions

 TAO_Constraint_Evaluator (void)
 Constructor.
CORBA::Boolean evaluate_constraint (TAO_Constraint *root)
int evaluate_preference (TAO_Constraint *root, TAO_Literal_Constraint &result)
virtual int visit_constraint (TAO_Unary_Constraint *constraint)
virtual int visit_with (TAO_Unary_Constraint *unary_with)
virtual int visit_min (TAO_Unary_Constraint *unary_min)
virtual int visit_max (TAO_Unary_Constraint *unary_max)
virtual int visit_first (TAO_Noop_Constraint *noop_first)
virtual int visit_random (TAO_Noop_Constraint *noop_random)
virtual int visit_and (TAO_Binary_Constraint *boolean_and)
virtual int visit_or (TAO_Binary_Constraint *boolean_or)
virtual int visit_not (TAO_Unary_Constraint *unary_not)
 Logically negates the value of the operand.
virtual int visit_exist (TAO_Unary_Constraint *unary_exist)
virtual int visit_unary_minus (TAO_Unary_Constraint *unary_minus)
 Mathematically negates the return value the operand.
virtual int visit_add (TAO_Binary_Constraint *boolean_add)
 Add the results of evaluating the left and right operands.
virtual int visit_sub (TAO_Binary_Constraint *boolean_sub)
 Subtract the results of evaluating the left and right operands.
virtual int visit_mult (TAO_Binary_Constraint *boolean_mult)
 Multiply the results of evaluating the left and right operands.
virtual int visit_div (TAO_Binary_Constraint *boolean_div)
 Divide the results of evaluating the left and right operands.
virtual int visit_twiddle (TAO_Binary_Constraint *binary_twiddle)
 Determines if the right operand is a substring of the left.
virtual int visit_in (TAO_Binary_Constraint *binary_in)
virtual int visit_less_than (TAO_Binary_Constraint *boolean_lt)
virtual int visit_less_than_equal (TAO_Binary_Constraint *boolean_lte)
virtual int visit_greater_than (TAO_Binary_Constraint *boolean_gt)
virtual int visit_greater_than_equal (TAO_Binary_Constraint *boolean_gte)
virtual int visit_equal (TAO_Binary_Constraint *boolean_eq)
virtual int visit_not_equal (TAO_Binary_Constraint *boolean_neq)
virtual int visit_literal (TAO_Literal_Constraint *literal)
 Copy the value of the literal into the result container.
virtual int visit_property (TAO_Property_Constraint *literal)
 Copy the value of the property into the result container.

Protected Attributes

TAO_Lookup_Table props_
 The map of property names to their values for a property.
Operand_Queue queue_
 The result of a non_boolean operation.

Private Member Functions

void do_the_op (int operation)
 Method for performing a arithmetic or comparison operation.
int visit_bin_op (TAO_Binary_Constraint *op, int operation)
 Method for evaluating a binary operation.
CORBA::Boolean sequence_does_contain (CORBA::Any *sequence, TAO_Literal_Constraint &element)
 TAO_Constraint_Evaluator (const TAO_Constraint_Evaluator &)
 Disallow copying.
TAO_Constraint_Evaluatoroperator= (const TAO_Constraint_Evaluator &)

Detailed Description

TAO_Constraint_Evaluator traverse a constraint expression tree, and determines whether an offer fits the constraints represented by the tree.

Using the Visitor pattern, the TAO_Constraint_Evaluator has each node of the expression tree call back to it with the method designated for its type. In that method, the visitor will evaluate its operands and perform the operation designated by that node's type, and return the result. Note: the TAO_Constraint_Evaluator assumes the tree is semantically correct, that is, the validate method on TAO_Constraint_Validator return true. The only possible evaluation time errors are a divide by a property whose value is zero and undefined properties.


Constructor & Destructor Documentation

TAO_Constraint_Evaluator::TAO_Constraint_Evaluator ( void  )

Constructor.

TAO_Constraint_Evaluator::TAO_Constraint_Evaluator ( const TAO_Constraint_Evaluator ) [private]

Disallow copying.


Member Function Documentation

void TAO_Constraint_Evaluator::do_the_op ( int  operation) [private]

Method for performing a arithmetic or comparison operation.

CORBA::Boolean TAO_Constraint_Evaluator::evaluate_constraint ( TAO_Constraint root)

Evaluate returns 1 if the offer satisfies the constraints represented by the the expression tree rooted at <root>, 0 if it doesn't. If an error occurs during process, the constraint automatically fails.

int TAO_Constraint_Evaluator::evaluate_preference ( TAO_Constraint root,
TAO_Literal_Constraint result 
)

The result of the preference evaluation is stored in result. The method returns 0 upon success, -1 upon failure.

TAO_Constraint_Evaluator& TAO_Constraint_Evaluator::operator= ( const TAO_Constraint_Evaluator ) [private]
CORBA::Boolean TAO_Constraint_Evaluator::sequence_does_contain ( CORBA::Any *  sequence,
TAO_Literal_Constraint element 
) [private]

Determine if sequence contains element, a literal of the same simple type as <sequence_type>. Return true in this eventuality.

int TAO_Constraint_Evaluator::visit_add ( TAO_Binary_Constraint boolean_add) [virtual]

Add the results of evaluating the left and right operands.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_and ( TAO_Binary_Constraint boolean_and) [virtual]

Takes the logical and of the results of both operands. Note that in the case where the left operand returns zero, the result is immediately known.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_bin_op ( TAO_Binary_Constraint op,
int  operation 
) [private]

Method for evaluating a binary operation.

int TAO_Constraint_Evaluator::visit_constraint ( TAO_Unary_Constraint constraint) [virtual]
int TAO_Constraint_Evaluator::visit_div ( TAO_Binary_Constraint boolean_div) [virtual]

Divide the results of evaluating the left and right operands.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_equal ( TAO_Binary_Constraint boolean_eq) [virtual]
int TAO_Constraint_Evaluator::visit_exist ( TAO_Unary_Constraint unary_exist) [virtual]

The property exists if its name is bound to a value in the <props_> map.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_first ( TAO_Noop_Constraint noop_first) [virtual]
int TAO_Constraint_Evaluator::visit_greater_than ( TAO_Binary_Constraint boolean_gt) [virtual]
int TAO_Constraint_Evaluator::visit_greater_than_equal ( TAO_Binary_Constraint boolean_gte) [virtual]
int TAO_Constraint_Evaluator::visit_in ( TAO_Binary_Constraint binary_in) [virtual]

Determines if the sequence represented by the right operand contains the left operand.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_less_than ( TAO_Binary_Constraint boolean_lt) [virtual]
int TAO_Constraint_Evaluator::visit_less_than_equal ( TAO_Binary_Constraint boolean_lte) [virtual]
int TAO_Constraint_Evaluator::visit_literal ( TAO_Literal_Constraint literal) [virtual]

Copy the value of the literal into the result container.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_max ( TAO_Unary_Constraint unary_max) [virtual]
int TAO_Constraint_Evaluator::visit_min ( TAO_Unary_Constraint unary_min) [virtual]
int TAO_Constraint_Evaluator::visit_mult ( TAO_Binary_Constraint boolean_mult) [virtual]

Multiply the results of evaluating the left and right operands.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_not ( TAO_Unary_Constraint unary_not) [virtual]

Logically negates the value of the operand.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_not_equal ( TAO_Binary_Constraint boolean_neq) [virtual]
int TAO_Constraint_Evaluator::visit_or ( TAO_Binary_Constraint boolean_or) [virtual]

Takes the logical or of the results of both operands. Note that in the case where the left operand returns one, the result is immediately known.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_property ( TAO_Property_Constraint literal) [virtual]

Copy the value of the property into the result container.

Implements TAO_Constraint_Visitor.

Reimplemented in TAO_Trader_Constraint_Evaluator.

int TAO_Constraint_Evaluator::visit_random ( TAO_Noop_Constraint noop_random) [virtual]
int TAO_Constraint_Evaluator::visit_sub ( TAO_Binary_Constraint boolean_sub) [virtual]

Subtract the results of evaluating the left and right operands.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_twiddle ( TAO_Binary_Constraint binary_twiddle) [virtual]

Determines if the right operand is a substring of the left.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_unary_minus ( TAO_Unary_Constraint unary_minus) [virtual]

Mathematically negates the return value the operand.

Implements TAO_Constraint_Visitor.

int TAO_Constraint_Evaluator::visit_with ( TAO_Unary_Constraint unary_with) [virtual]

Member Data Documentation

The map of property names to their values for a property.

The result of a non_boolean operation.


The documentation for this class was generated from the following files:
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