DataProvider::AbstractDataProviderRecordIterator Class Reference

Defines the abstract class for data provider iterators; the destructor releases the iterator. More...

#include <AbstractDataProviderRecordIterator.qc.dox.h>

Inheritance diagram for DataProvider::AbstractDataProviderRecordIterator:

Public Member Methods
	constructor (*bool requires_result, *int max_records)
	Creates the object and optionally sets the bulk iteration block size.
*AbstractDataProviderBulkRecordInterface	getBulkApi (int block_size=DefaultBlockSize)
	Returns the bulk data interface if supported.
*int	getMaxRecords ()
	Returns the 'max_records' value.
int	getRecordCount ()
	Returns the number of records returned so far.
*hash< string, AbstractDataField >	getRecordType ()
	Returns the record description, if available.
abstract hash< auto >	getValue ()
	returns a single record if the iterator is valid
bool	next ()
	Positions the iterator on the next record if possible, returns True if successful.
bool	requiresResult ()
	Returns the 'requires_result' flag.
bool	supportsBulkApi ()
	Returns True if the iterator supports bulk operation.

Public Attributes
const	DefaultBlockSize = 1000
	Default block size.

Private Member Methods
auto	doMemberGate (string key)
	Returns the value of the given field in the current record, if the iterator is valid.
abstract bool	nextImpl ()
	Positions the iterator on the next record if possible, returns True if successful.

Static Private Member Methods
static bool	evalOperator (string field, hash< auto > cmd, hash< auto > op, hash< auto > record)
	Evaluates a generic search operator on the field value and record and returns the result.
static bool	matchGeneric (hash< auto > record, *hash< auto > where_cond)
	Checks if the current record matches the search criteria.
static bool	matchGeneric (hash< auto > record, hash< DataProviderExpression > where_cond)
	Checks if the current record matches the search criteria.
static bool	matchGenericValue (auto expects, auto val)
	Match a single value.

Private Attributes
*int	max_records
	Max records.
int	record_count = 0
	Number of records returned.
bool	requires_result
	Requires result.

Detailed Description

Defines the abstract class for data provider iterators; the destructor releases the iterator.

this class also implements generic search APIs that can be used to filter record sets for data providers that do not support native search / filtering APIs

Member Function Documentation

doMemberGate()

auto DataProvider::AbstractDataProviderRecordIterator::doMemberGate ( string  key )

private

Returns the value of the given field in the current record, if the iterator is valid.

Parameters

key	the name of the field

Returns

the value of the given field in the current record, if the iterator is valid

Exceptions

FIELD-ERROR

invalid or unknown field name

getBulkApi()

*AbstractDataProviderBulkRecordInterface DataProvider::AbstractDataProviderRecordIterator::getBulkApi

(

int

block_size = DefaultBlockSize

)

Returns the bulk data interface if supported.

Returns

the bulk data interface if supported

Note

This base class method returns DefaultBulkRecordIterface by default

getRecordType()

*hash< string, AbstractDataField > DataProvider::AbstractDataProviderRecordIterator::getRecordType

(

)

Returns the record description, if available.

This base class method returns NOTHING; reimplement in subclasses to provide a record type

getValue()

abstract hash< auto > DataProvider::AbstractDataProviderRecordIterator::getValue

(

)

returns a single record if the iterator is valid

Exceptions

INVALID-ITERATOR

the iterator is not pointing at a valid element

matchGeneric() [1/2]

static bool DataProvider::AbstractDataProviderRecordIterator::matchGeneric ( hash< auto >  record, *hash< auto >  where_cond  )

staticprivate

Checks if the current record matches the search criteria.

in case of a hash value, if the hash was created by a search operator function, then that search operation is applied to the input, otherwise a recursive partial match with only the keys given in the value to be checked is performed

matchGeneric() [2/2]

static bool DataProvider::AbstractDataProviderRecordIterator::matchGeneric ( hash< auto >  record, hash< DataProviderExpression >  where_cond  )

staticprivate

Checks if the current record matches the search criteria.

in case of a hash value, if the hash was created by a search operator function, then that search operation is applied to the input, otherwise a recursive partial match with only the keys given in the value to be checked is performed

matchGenericValue()

static bool DataProvider::AbstractDataProviderRecordIterator::matchGenericValue ( auto  expects, auto  val  )

staticprivate

Match a single value.

in case of a hash value, a recursive partial match with only the keys given in the value to be checked is performed

next()

bool DataProvider::AbstractDataProviderRecordIterator::next

(

)

Positions the iterator on the next record if possible, returns True if successful.

Returns

True if the iterator was advanced to the next record, False if no more records are available

Note

Calling getValue() after this method returns False results in an exception

Exceptions

NO-DATA	no data available to return and requires_result is set
MAX-RECORDS-EXCEEDED	the maximum number of records has been exceeded as set by max_records

nextImpl()

abstract bool DataProvider::AbstractDataProviderRecordIterator::nextImpl ( )

private

Positions the iterator on the next record if possible, returns True if successful.

Returns

True if the iterator was advanced to the next record, False if no more records are available

supportsBulkApi()

bool DataProvider::AbstractDataProviderRecordIterator::supportsBulkApi

(

)

Returns True if the iterator supports bulk operation.

Returns

True if the iterator supports bulk operation

Note

This base class method returns True by default and simulates a bulk iterator