public package Foswiki::Iterator

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Perl Module:

Child packagesChild packages

• Foswiki::Iterator::AggregateEventIterator
• Foswiki::Iterator::DBIterator
• Foswiki::Iterator::EventIterator
• Foswiki::Iterator::FilterIterator
• Foswiki::Iterator::MergeEventIterator
• Foswiki::Iterator::NumberRangeIterator - Iterator over a range of integer values, with programmable increment.
• Foswiki::Iterator::PagerIterator
• Foswiki::Iterator::ProcessIterator

public package Foswiki::Iterator

This class cannot be instantiated on its own - it is an interface specification for iterators. See http://en.wikipedia.org/wiki/Iterator_Pattern for more information on the iterator pattern.

The interface only supports forward iteration. Subclasses should use this as their base class (so that $it→isa("Foswiki::Iterator") returns true), and must implement hasNext and next per the specification below.

See Foswiki::ListIterator for an example implementation.

hasNext() → $boolean

Returns true if the iterator has more items, or false when the iterator is exhausted.

next() → $data

Return the next data in the iteration.

The data may be any type.

The iterator object can be customised to pre- and post-process entries from the list before returning them. This is done by setting two fields in the iterator object:

• {filter} can be defined to be a sub that filters each entry. The entry will be ignored (next() will not return it) if the filter returns false.
• {process} can be defined to be a sub to process each entry before it is returned by next. The value returned from next is the value returned by the process function.

reset() → $boolean

resets the iterator to the begining - returns false if it can't

ObjectMethod all() → @list

Exhaust the iterator. Return all remaining elements in the iteration as a list. The returned list should be considered to be immutable.

The default implementation simply runs the iterator to its end.