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https://issues.apache.org/jira/browse/EDGENT-91?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Dale LaBossiere resolved EDGENT-91.
-----------------------------------
Resolution: Fixed
Not sure when the work was done, or the PR, but TStream now supports `join()`
and `joinLast()`
> Support joining a stream against another stream/window
> ------------------------------------------------------
>
> Key: EDGENT-91
> URL: https://issues.apache.org/jira/browse/EDGENT-91
> Project: Edgent
> Issue Type: Improvement
> Reporter: Will Marshall
> Assignee: Will Marshall
>
> Quarks should support the ability to join a stream against another stream or
> window. The interface would look something like this:
> {code}
> <J, U, K> TStream<J> join(Function<T, K> keyer, TWindow<U, K> window,
> BiFunction<T, List<U>, J> joiner);
>
> <J, U, K> TStream<J> joinLast(TStream<U> lastStream, BiFunction<T, U, J>
> joiner);
> <J, U, K> TStream<J> joinLast(Function<T, K> keyer, TStream<U>
> lastStream, Function<U, K> lastStreamKeyer, BiFunction<T, U, J> joiner);
> {code}
> Copied from:
> http://ibmstreams.github.io/streamsx.topology/doc/javadoc/index.html
> For *join(Function<T, K> keyer, TWindow<U, K> window, BiFunction<T, List<U>,
> J> joiner)*:
> Join this stream with a partitioned window of type U with key type K. For
> each tuple on this stream, it is joined with the contents of window for the
> key keyer.apply(tuple). Each tuple is passed into joiner and the return value
> is submitted to the returned stream. If call returns null then no tuple is
> submitted.
> For *joinLast(Function<T, K> keyer, TStream<U> lastStream, Function<U, K>
> lastStreamKeyer, BiFunction<T, U, J> joiner)*:
> Join this stream with the last tuple seen on a stream of type U with
> partitioning. For each tuple on this stream, it is joined with the last tuple
> seen on lastStream with a matching key (of type K). Each tuple t on this
> stream will match the last tuple u on lastStream if
> keyer.apply(t).equals(lastStreamKeyer.apply(u)) is true. The assumption is
> made that the key classes correctly implement the contract for equals and
> hashCode(). Each tuple is passed into joiner and the return value is
> submitted to the returned stream. If call returns null then no tuple is
> submitted.
> For *joinLast(TStream<U> lastStream, BiFunction<T, U, J> joiner)*:
> Join this stream with the last tuple seen on a stream of type U. For each
> tuple on this stream, it is joined with the last tuple seen on lastStream.
> Each tuple is passed into joiner and the return value is submitted to the
> returned stream. If call returns null then no tuple is submitted.
> This is a simplified version of join(TWindow, BiFunction) where instead the
> window contents are passed as a single tuple of type U rather than a list
> containing one tuple. If no tuple has been seen on lastStream then null will
> be passed as the second argument to joiner.
> *Issues:*
> - The definition of Oplet<I, O> requires that all input tuples be of the same
> type. If streamA and streamB are of different types, it's not clear how to
> create a "join" oplet where one input port has the tuples of streamA and
> another has the tuples of streamB.
> - The windowing library doesn't currently support accessing the contents of a
> partition from a quarks.window.Window reference.
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