FixedLengthUtil::FixedLengthDataIterator Class Reference

Structured line iterator for fixed-length line strings allowing efficient "pipelined" processing. More...

#include <FixedLengthDataIterator.qc.dox.h>

Inheritance diagram for FixedLengthUtil::FixedLengthDataIterator:

Public Member Methods
	constructor (string data, hash< auto > spec, *hash< auto > opts)
	Instantiates the FixedLengthDataIterator object. More...
Public Member Methods inherited from FixedLengthUtil::FixedLengthAbstractIterator
bool	checkTransition (*string from, *string to)
	A verification function to be called for each line. This method can be overridden to achieve a begin-to-end validation of the whole input file. More...
	constructor (AbstractLineIterator li, hash< auto > spec, *hash< auto > opts)
	Instantiates the FixedLengthAbstractIterator object. More...
*hash< auto >	getValue ()
	Returns the current record as a hash. More...
bool	identifyRecord (list< auto > rec_rule, string input_line)
	Attempts to identify a single record.
string	identifyType (string input_line)
	Identify a fixed-length line type using identifyTypeImpl(), that may be overridden if necessary. More...
*string	identifyTypeImpl (string input_line)
	Identify a fixed-length line type, given the raw line string. This method performs a lookup to a precalculated table based on line lengths (see constructor()). In case different criteria are needed, eg. when two line types in a spec have the same length and no unique resolving rule are specified, this method needs to be overridden, and will throw an exception, because the precalculated mapping will be empty. More...
bool	next ()
	Moves the current line / record position to the next line / record; returns False if there are no more lines to iterate. More...
auto	transform (auto value, hash< auto > type)
	parses the input value based on global configuration and the current field definition
Public Member Methods inherited from FixedLengthUtil::FixedLengthBase
	constructor (hash< auto > m_specs, *hash< auto > m_opts)
	Creates the object from the record specifications.
*hash< string, AbstractDataField >	getRecordType ()
	Returns the description of the record type, if any.

Additional Inherited Members
Static Private Member Methods inherited from FixedLengthUtil::FixedLengthAbstractIterator
static *hash< auto >	checkOptions (*hash< auto > opts)
	Validate and prepare global fixed-length options. More...
Private Attributes inherited from FixedLengthUtil::FixedLengthAbstractIterator
hash	m_resolve_by_length
	hash of type without rule, i.e.potentially conflicting records; key = record length, value = list of no-rule type names
Private Attributes inherited from FixedLengthUtil::FixedLengthBase
const	GlobalOptionMap
	Translates from global options to data provider options.
*hash< auto >	m_opts
	Global input or output options.
hash< auto >	m_specs
	The record specifications.

Detailed Description

Structured line iterator for fixed-length line strings allowing efficient "pipelined" processing.

Example:

string data = "00001AV\n00002BN\00003CZ\n";
 
hash<auto> specs = {
    "type1": {
        "col1": {"length": 5, "type": "int"},
        "col2": {"length": 2, "type": "string"},
    },
    "type2": {
        "col3": {"length": 1, "type": "string"},
        "col4": {"length": 3, "type": "string"},
        "col5": {"length": 8, "type": "date", "format": "DDMMYYYY", "timezone": "Europe/Prague"},
    },
};
 
hash<auto> global_options = {
    "encoding"    : "UTF-8",
    "eol"         : "\n",
    "ignore_empty": True,
    "timezone"    : "Europe/Prague", # used if not overridden in a date field specification
};
 
FixedLengthDataIterator i(data, specs, global_options);
while (i.next()) {
    operation_with_hash(i.getValue())
}

See also

• FixedLengthIterator for a stream-based class providing the same functionality as this class in a more generic way

Member Function Documentation

constructor()

FixedLengthUtil::FixedLengthDataIterator::constructor	(	string	data,
		hash< auto >	spec,
		*hash< auto >	opts
	)

Instantiates the FixedLengthDataIterator object.

Example:

hash<auto> specs = {
    "type1": {
        "col1": {"length": 5, "type": "int"},
        "col2": {"length": 2, "type": "string"},
    },
    "type2": {
        "col3": {"length": 1, "type": "string"},
        "col4": {"length": 3, "type": "string"},
        "col5": {"length": 8, "type": "date", "format": "DDMMYYYY", "timezone": "Europe/Prague"},
    },
};
 
hash<auto> global_options = {
    "encoding"    : "UTF-8",
    "eol"         : "\n",
    "ignore_empty": True,
    "timezone"    : "Europe/Prague", # used if not overridden in a date field specification
};
 
FixedLengthDataIterator i(string, specs, global_options);
while (i.next()) {
    operation_with_hash(i.getValue())
}

Parameters

data	The input string to process
spec	Fixed-length line specification; see Specification Hash for more information
opts	Global options; see Global Options for valid values