[COLLECTIONS-795] provide a PairIterator to zip two iterators of different types. - ASF JIRA

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Details

Type: New Feature
Status: Open
Priority: Minor
Resolution: Unresolved
Affects Version/s: None
Fix Version/s: None
Component/s: Iterator
Labels:
None

External issue URL:
https://github.com/apache/commons-collections/pull/238

Description

ZippingIterator provides a way to simulatenously iterate over multiple iterators of the same-type.

The proposed pair iterator allows simultaneously iterating over two iterators of different type, like the example below:

Iterator<L> leftIterator =  ...;
Iterator<R> rightIterator = ...;

PairIterator<L,R> pairIterator = PairIterator.of(leftIterator, rightIterator);

while (pairIterator.hasNext()) {
   ImmutablePair<L,R> item = pairIterator.next();
   ...
}

Another convenience could be to use an Iterable for easy for-each constructs.

List<Integer> studentIds = ...
List<String> studentNames = ...

for (PairedItem<Integer, String> items : IterableUtils.pairedIterable(studentIds, studentNames) {
  Integer studentId = item.getLeft();
  String studentName = item.getRight();
  ...
}