Qore::AbstractLineIterator Class Reference

This class defines an abstract interface for line iterators. More...

Inheritance diagram for Qore::AbstractLineIterator:

Public Member Methods
abstract string	getLine ()
	Returns the current line in the data or throws an INVALID-ITERATOR exception if the iterator is invalid. More...
list< string >	getSplitLine (string sep, string quote, string eol="\n", bool trim_unquoted=False)
	Returns the current line and splits the string into a list of components based on a separator string and a quote character. More...
abstract string	getValue ()
	Returns the current line in the data or throws an INVALID-ITERATOR exception if the iterator is invalid. More...
abstract int	index ()
	Returns the current iterator line number (the first line is line 1) or 0 if not pointing at a valid element. More...
abstract bool	next ()
	Moves the current position to the next line; returns False if there are no more lines to read. More...
abstract bool	valid ()
	Returns True if the iterator is currently pointing at a valid element, False if not. More...

Detailed Description

This class defines an abstract interface for line iterators.

Classes inheriting this class can be used to iterate lines from various sources.

Since

Qore 0.8.13

Member Function Documentation

getLine()

abstract string Qore::AbstractLineIterator::getLine ( )

pure virtual

Returns the current line in the data or throws an INVALID-ITERATOR exception if the iterator is invalid.

Returns

the current line in the data

Example:

while (i.next()) {
    printf("+ %y\n", i.getLine());
}

Exceptions

INVALID-ITERATOR

the iterator is not pointing at a valid element

Implemented in Qore::InputStreamLineIterator, Qore::FileLineIterator, and Qore::DataLineIterator.

getSplitLine()

list<string> Qore::AbstractLineIterator::getSplitLine	(	string	sep,
		string	quote,
		string	eol = "\n",
		bool	trim_unquoted = False
	)

Returns the current line and splits the string into a list of components based on a separator string and a quote character.

Retrieves additional lines if the last is quoted and is not terimated; this way fields can contain multiple lines

The quote character can appear as the first part of a field, in which case it is assumed to designate the entire field. If instances of the quote character are found in the field preceded by a backquote character ("\"), then these quote characters are included as part of the field's text and not treated as quote characters.
Also the separator character can appear as a part of a field with this variant.
This variant is useful for parsing CSV files, for example.

Code Flags:

RET_VALUE_ONLY

Parameters

sep	the separator string; if the separator string is not found in the string to split, then a list with only one element containing the entire string argument is returned'; if this string has a different character encoding than str, then it will be converted to str's character encoding
quote	the quote character
eol	the end of line string to be readded in case of a field split between lines
trim_unquoted	remove leading and trailing whitespace from unquoted fields

Returns

a list of each component of a string separated by a separator string, with the separator and any enclosing quote characters removed

Example:

list<string> list = "some,'text with spaces, and commas, here is another one! ,',here".split(",", "'");
# returns ("some", ", and commas, here is another one! ,", "here")

Exceptions

ENCODING-CONVERSION-ERROR	this exception could be thrown if the string arguments have different character encodings and an error occurs during encoding conversion
SPLIT-ERROR	field missing closing quote character; extra text following quoted field

Since

• Qore 0.9.8 added this method

getValue()

abstract string Qore::AbstractLineIterator::getValue ( )

pure virtual

Returns the current line in the data or throws an INVALID-ITERATOR exception if the iterator is invalid.

This method calls AbstractLineIterator::getLine() internally.

Returns

the current line in the data

Example:

while (i.next()) {
    printf("+ %y\n", i.getValue());
}

Exceptions

INVALID-ITERATOR

the iterator is not pointing at a valid element

See also

AbstractLineIterator::getLine()

Implements Qore::AbstractIterator.

Implemented in Qore::InputStreamLineIterator, Qore::FileLineIterator, and Qore::DataLineIterator.

index()

abstract int Qore::AbstractLineIterator::index ( )

pure virtual

Returns the current iterator line number (the first line is line 1) or 0 if not pointing at a valid element.

Returns

the current iterator line number (the first line is line 1) or 0 if not pointing at a valid element

Example:

while (i.next()) {
    printf("+ %d: %y\n", i.index(), i.getLine());
}

Implemented in Qore::InputStreamLineIterator, Qore::FileLineIterator, and Qore::DataLineIterator.

next()

abstract bool Qore::AbstractLineIterator::next ( )

pure virtual

Moves the current position to the next line; returns False if there are no more lines to read.

This method will return True again after it returns False once if data is not empty, otherwise it will always return False. The iterator object should not be used after this method returns False.

Returns

False if there are no more lines in the source (in which case the iterator object is invalid and should not be used); True if successful (meaning that the iterator object is valid)

Example:

while (i.next()) {
    printf("line: %y\n", i.getLine());
}

Implements Qore::AbstractIterator.

Implemented in Qore::InputStreamLineIterator, Qore::FileLineIterator, and Qore::DataLineIterator.

valid()

abstract bool Qore::AbstractLineIterator::valid ( )

pure virtual

Returns True if the iterator is currently pointing at a valid element, False if not.

Returns

True if the iterator is currently pointing at a valid element, False if not

Example:

if (i.valid())
    printf("current value: %y\n", i.getValue());

Implements Qore::AbstractIterator.

Implemented in Qore::InputStreamLineIterator, Qore::FileLineIterator, and Qore::DataLineIterator.