ListWalker

ListWalker is a term used in software development to describe a component or mechanism that traverses the elements of a list or list-like sequence. It is not a fixed standard, but a pattern employed across languages and frameworks to expose controlled iteration over a collection.

Typical responsibilities of a ListWalker include maintaining traversal state, providing access to the current element, and advancing to subsequent elements. Most implementations offer operations such as next, hasNext, reset, and current, and may expose additional capabilities like peeking ahead, jumping to a specific index, or filtering and transforming elements as they are walked.

Use cases for a ListWalker include processing large or streaming lists without loading all elements at once, rendering user interfaces with virtualized lists, or implementing pipelines where each element is processed in sequence. Some variants are read-only, simply iterating over a fixed collection, while others are mutable and allow insertions, removals, or reordering during traversal.

In different ecosystems the concept appears under various names. In Python, similar behavior is provided by iterators and generators; Java offers ListIterator and streams; UI frameworks often implement walkers to map data to visible components. The term “walker” may also appear in documentation for custom traversal policies or in domain-specific languages as a means to define iteration strategies.

See also: iterator, enumerator, generator, cursor, stream, pagination.