Class StreamEnhancementExamples

java.lang.Object

net.jrodolfo.java_evolution.java09.StreamEnhancementExamples

public class StreamEnhancementExamples
extends Object

Demonstrates Stream API enhancements introduced in Java 9.

Java 8 streams made pipeline-style data processing practical, but some common stream shapes still required custom logic: process ordered values until a boundary, skip ordered values until a boundary, safely stream a possibly null value, or generate values with a built-in stopping condition.

Java 9 added ordered stream slicing with takeWhile and dropWhile, nullable stream creation with Stream.ofNullable, and a bounded form of Stream.iterate.

Constructor Summary

Constructors

Constructor	Description
StreamEnhancementExamples()

Method Summary

Modifier and Type	Method	Description
List<String>	listFromNullableValue(String value)	Uses Stream.ofNullable(Object) to create either a one-element stream or an empty stream.
List<Integer>	numbersBeforeTen(List<Integer> numbers)	Uses Stream.takeWhile(java.util.function.Predicate) to keep values only until the first value that does not match.
List<Integer>	numbersFromTenOnward(List<Integer> numbers)	Uses Stream.dropWhile(java.util.function.Predicate) to skip values until the first value that does not match.
List<Integer>	powersOfTwoBelowOneHundred()	Uses the Java 9 bounded form of Stream.iterate(Object, java.util.function.Predicate, java.util.function.UnaryOperator).

Methods inherited from class Object

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

Constructor Details

StreamEnhancementExamples

public StreamEnhancementExamples()

Method Details

numbersBeforeTen

public List<Integer> numbersBeforeTen(List<Integer> numbers)

Uses Stream.takeWhile(java.util.function.Predicate) to keep values only until the first value that does not match.

Parameters:

numbers - ordered numbers to inspect

Returns:

the numbers before the first value greater than or equal to 10

numbersFromTenOnward

public List<Integer> numbersFromTenOnward(List<Integer> numbers)

Uses Stream.dropWhile(java.util.function.Predicate) to skip values until the first value that does not match.

Parameters:

numbers - ordered numbers to inspect

Returns:

the numbers starting at the first value greater than or equal to 10

listFromNullableValue

public List<String> listFromNullableValue(String value)

Uses Stream.ofNullable(Object) to create either a one-element stream or an empty stream.

Parameters:

value - the possibly null value

Returns:

a list containing the value when non-null, otherwise an empty list

powersOfTwoBelowOneHundred

public List<Integer> powersOfTwoBelowOneHundred()

Uses the Java 9 bounded form of Stream.iterate(Object, java.util.function.Predicate, java.util.function.UnaryOperator).

Returns:

powers of two that are smaller than 100