Class TeeingCollectorExamples

java.lang.Object

net.jrodolfo.java_evolution.java12.TeeingCollectorExamples

public class TeeingCollectorExamples
extends Object

Demonstrates Collectors.teeing(java.util.stream.Collector, java.util.stream.Collector, java.util.function.BiFunction), introduced in Java 12.

Before Java 12, computing two independent summaries from one stream often required two stream passes or a custom collector. That made simple aggregate combinations more complex than necessary.

teeing solves this by sending the same input into two downstream collectors and combining their results with a final function.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	TeeingCollectorExamples.NumberSummary	Small Java 12-style data class for teeing collector results.

Constructor Summary

Constructors

Constructor	Description
TeeingCollectorExamples()

Method Summary

Modifier and Type	Method	Description
int	range(List<Integer> numbers)	Computes minimum and maximum values in one stream pass.
TeeingCollectorExamples.NumberSummary	summarize(List<Integer> numbers)	Computes a count and average in one stream pass.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TeeingCollectorExamples

public TeeingCollectorExamples()

Method Details

range

public int range(List<Integer> numbers)

Computes minimum and maximum values in one stream pass.

Parameters:

numbers - the numbers to summarize

Returns:

the range between the minimum and maximum values

summarize

public TeeingCollectorExamples.NumberSummary summarize(List<Integer> numbers)

Computes a count and average in one stream pass.

Parameters:

numbers - the numbers to summarize

Returns:

a simple summary object