Terminal operation
A terminal operation ends a stream or sequence pipeline, triggers evaluation of preceding transformations, and produces a final result or side effect.
100 Java Mistakes and How to Avoid Them
A terminal operation is a stream operation that triggers evaluation of a Java stream pipeline and produces a final result or side effect.
- How it is used
- Triggers Stream pipeline evaluation to obtain a result rather than leave filtering or sorting unevaluated.
- How deep it goes
- Defines pipeline execution and examines laziness, side-effect risks, and single-consumption failures without Stream implementation internals.
- Examples
- Uses filtering empty strings, partitioning strings by a substring, counting before anyMatch(), and reusing a stream in a loop.
- What you can do after
- Diagnose/debug with it by recognizing unevaluated pipelines and streams consumed before a later operation.
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Kotlin in Action, 2E
A terminal operation is a sequence operation that produces a final result and triggers evaluation of the preceding transformations.
- How it is used
- Triggers lazy sequence pipelines and cold flow pipelines when a result, collection, subscription, or side effect is required.
- How deep it goes
- Explains deferred evaluation, element-by-element processing, early stopping, suspension, cancellation, and sequence performance trade-offs.
- Examples
- Uses squared numbers with `toList` and `find`, natural-number `sum`, hidden-directory `any`, and temperature-flow `collect` or `first`.
- What you can do after
- Apply it via Kotlin sequence and Flow operators to materialize results, aggregate values, collect emissions, or stop after a needed value.
The Art of Code
A terminal operation ends a pipeline, triggers its deferred processing, and produces or materializes a final result.
- How it is used
- Ends functional pipelines by triggering deferred transformations and producing a materialized result.
- How deep it goes
- Explains laziness, execution, materialization, single-use consumption, and common operations, without detailing their internal implementations.
- Examples
- Uses Java stream pipelines that filter recent books, map authors, and terminate with toList(), alongside analogous sequence and collection examples.
- What you can do after
- Apply it via Java Stream API to execute transformations and obtain a final collection or aggregate.
Related concepts
- collectincludes · collect is an operation that consumes produced values and gathers them into a collection or other result.
- flowuses · A Flow is an asynchronous stream abstraction whose values are collected over time and whose producer may be cold, executing anew for each collection.
- first elementincludes · A first operation retrieves the initial element of a sequence or collection, optionally subject to a predicate, and indicates when no matching element exists.
- printincludes · Print is a programming operation that writes a value or its textual representation to an output destination, often standard output.
- suspending functionkind of · A suspending function can pause and later resume execution without blocking the underlying thread.
- streamingpart of · Streaming is the incremental handling of a sequence of data items, including their processing, transfer, or consumption as they become available.
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