libdap  Updated for version 3.17.0
libdap::ConstraintEvaluator Class Reference

Evaluate a constraint expression. More...

#include <ConstraintEvaluator.h>

List of all members.

Public Types

typedef std::vector< Clause * >
::const_iterator 
Clause_citer
typedef std::vector< Clause * >
::iterator 
Clause_iter
typedef std::vector< BaseType * >
::const_iterator 
Constants_citer
typedef std::vector< BaseType * >
::iterator 
Constants_iter

Public Member Functions

void append_clause (int op, rvalue *arg1, rvalue_list *arg2)
 Add a clause to a constraint expression.
void append_clause (bool_func func, rvalue_list *args)
 Add a clause to a constraint expression.
void append_clause (btp_func func, rvalue_list *args)
 Add a clause to a constraint expression.
void append_constant (BaseType *btp)
bool boolean_expression ()
 Does the current constraint expression return a boolean value?
Clause_iter clause_begin ()
Clause_iter clause_end ()
bool clause_value (Clause_iter &i, DDS &dds)
BaseTypeeval_function (DDS &dds, const std::string &dataset)
 Evaluate a function-valued constraint expression.
DDSeval_function_clauses (DDS &dds)
 Evaluate a function-valued constraint expression that contains several function calls.
DataDDSeval_function_clauses (DataDDS &dds)
 Evaluate a function-valued constraint expression that contains several function calls. Takes and returns a DataDDS.
bool eval_selection (DDS &dds, const std::string &dataset)
 Evaluate a boolean-valued constraint expression. This is main method for the evaluator ans is called by the BaseType::serialize() methods.
bool find_function (const std::string &name, bool_func *f) const
 Find a Boolean function with a given name in the function list.
bool find_function (const std::string &name, btp_func *f) const
 Find a BaseType function with a given name in the function list.
bool find_function (const std::string &name, proj_func *f) const
 Find a projection function with a given name in the function list.
bool function_clauses ()
 Does the current constraint expression contain function clauses.
bool functional_expression ()
 Does the current constraint expression return a BaseType pointer? This method does not evaluate the clause, it provides information to the evaluator regarding _how_ to evaluate the clause.
void parse_constraint (const std::string &constraint, DDS &dds)
 Parse the constraint expression given the current DDS.

Friends

class func_name_is

Detailed Description

Evaluate a constraint expression.

Definition at line 42 of file ConstraintEvaluator.h.


Member Function Documentation

void libdap::ConstraintEvaluator::append_clause ( int  op,
rvalue arg1,
rvalue_list *  arg2 
)

Add a clause to a constraint expression.

This function adds an operator clause to the constraint expression.

Parameters:
opAn integer indicating the operator in use. These values are generated by bison.
arg1A pointer to the argument on the left side of the operator.
arg2A pointer to a list of the arguments on the right side of the operator.

Definition at line 115 of file ConstraintEvaluator.cc.

void libdap::ConstraintEvaluator::append_clause ( bool_func  func,
rvalue_list *  args 
)

Add a clause to a constraint expression.

This function adds a boolean function clause to the constraint expression.

Parameters:
funcA pointer to a boolean function from the list of supported functions.
argsA list of arguments to that function.

Definition at line 131 of file ConstraintEvaluator.cc.

void libdap::ConstraintEvaluator::append_clause ( btp_func  func,
rvalue_list *  args 
)

Add a clause to a constraint expression.

This function adds a real-valued (BaseType) function clause to the constraint expression.

Parameters:
funcA pointer to a BaseType function from the list of supported functions.
argsA list of arguments to that function.

Definition at line 147 of file ConstraintEvaluator.cc.

The Constraint Evaluator maintains a list of BaseType pointers for all the constants that the constraint expression parser generates. These objects are deleted by the Constraint Evaluator destructor. Note that there are no list accessors; these constants are never accessed from the list. The list is simply a convenient way to make sure the constants are disposed of properly.

Definition at line 161 of file ConstraintEvaluator.cc.

Does the current constraint expression return a boolean value?

Definition at line 311 of file ConstraintEvaluator.cc.

ConstraintEvaluator::Clause_iter libdap::ConstraintEvaluator::clause_begin ( )

Returns the first clause in a parsed constraint expression.

Definition at line 81 of file ConstraintEvaluator.cc.

ConstraintEvaluator::Clause_iter libdap::ConstraintEvaluator::clause_end ( )

Returns a reference to the end of the list of clauses in a parsed constraint expression. It does not reference the last clause

Definition at line 88 of file ConstraintEvaluator.cc.

bool libdap::ConstraintEvaluator::clause_value ( Clause_iter &  iter,
DDS dds 
)

Returns the value of the indicated clause of a constraint expression.

Definition at line 95 of file ConstraintEvaluator.cc.

BaseType * libdap::ConstraintEvaluator::eval_function ( DDS dds,
const std::string &  dataset 
)

Evaluate a function-valued constraint expression.

Deprecated:

Definition at line 206 of file ConstraintEvaluator.cc.

Evaluate a function-valued constraint expression that contains several function calls.

This method can be called for any function-valued constraint expression. Unlike eval_function(), it will package the return value in a new DDS object. The server should free this object once it has been serialized and sent.

Note:
While there is another type of function that can appear in a CE (a 'projection function') those are evaluated by the ce parser - they are used to insert new variables into the DDS as a side effect of CE evaluation. That kind of function can never appear here; these are all functions that return BaseType pointers.
Added for libdap 3.11

Definition at line 258 of file ConstraintEvaluator.cc.

Evaluate a function-valued constraint expression that contains several function calls. Takes and returns a DataDDS.

See also:
ConstraintEvaluator::eval_function_clauses(DataDDS &dds)
Note:
Added for libdap 3.11

Definition at line 287 of file ConstraintEvaluator.cc.

bool libdap::ConstraintEvaluator::eval_selection ( DDS dds,
const std::string &  dataset 
)

Evaluate a boolean-valued constraint expression. This is main method for the evaluator ans is called by the BaseType::serialize() methods.

Parameters:
ddsUse these variables when evaluating the expressions.
datasetThis string is passed to the read() methods.
Returns:
True if the expression is true, false otherwise.

Definition at line 331 of file ConstraintEvaluator.cc.

bool libdap::ConstraintEvaluator::find_function ( const std::string &  name,
bool_func *  f 
) const

Find a Boolean function with a given name in the function list.

Definition at line 167 of file ConstraintEvaluator.cc.

bool libdap::ConstraintEvaluator::find_function ( const std::string &  name,
btp_func *  f 
) const

Find a BaseType function with a given name in the function list.

Definition at line 173 of file ConstraintEvaluator.cc.

bool libdap::ConstraintEvaluator::find_function ( const std::string &  name,
proj_func *  f 
) const

Find a projection function with a given name in the function list.

Definition at line 179 of file ConstraintEvaluator.cc.

Does the current constraint expression contain function clauses.

This method does not evaluate the clauses, it provides information to the evaluator regarding _how_ to evaluate the clause.

Note:
Added for libdap 3.11
Returns:
True if the current constraint contains function clauses, otherwise returns False

Definition at line 228 of file ConstraintEvaluator.cc.

Does the current constraint expression return a BaseType pointer? This method does not evaluate the clause, it provides information to the evaluator regarding _how_ to evaluate the clause.

Returns:
True if the clause is a function that returns a BaseType* and false otherwise
Deprecated:

Definition at line 193 of file ConstraintEvaluator.cc.

void libdap::ConstraintEvaluator::parse_constraint ( const std::string &  constraint,
DDS dds 
)

Parse the constraint expression given the current DDS.

Evaluate the constraint expression; return the value of the expression. As a side effect, mark the DDS so that BaseType's mfuncs can be used to correctly read the variable's value and send it to the client.

Parameters:
constraintA string containing the constraint expression.
ddsThe DDS that provides the environment within which the constraint is evaluated.
Exceptions:
ThrowsError if the constraint does not parse.

Definition at line 365 of file ConstraintEvaluator.cc.


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