Class UnnamedVariablesPatternsExamples

java.lang.Object

net.jrodolfo.java_evolution.java22.UnnamedVariablesPatternsExamples

public class UnnamedVariablesPatternsExamples
extends Object

Demonstrates unnamed variables and patterns, finalized in Java 22.

Before Java 22, Java often required names for values that were intentionally unused. Those names could make code look as if the value mattered. The underscore marks the value as deliberately ignored in loops, lambdas, catch clauses, and patterns.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	UnnamedVariablesPatternsExamples.IntPairOperation	Small functional interface used to demonstrate an ignored lambda parameter.

Constructor Summary

Constructors

Constructor	Description
UnnamedVariablesPatternsExamples()

Method Summary

Modifier and Type	Method	Description
String	broadType(Object value)	Uses an unnamed pattern variable in a switch pattern.
int	countValues(Iterable<String> values)	Uses unnamed variables in a loop when only iteration count matters.
int	useOnlyFirstValue(int left, int right)	Uses an unnamed lambda parameter to show that one argument is intentionally ignored.

Methods inherited from class Object

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

Constructor Details

UnnamedVariablesPatternsExamples

public UnnamedVariablesPatternsExamples()

Method Details

useOnlyFirstValue

public int useOnlyFirstValue(int left,
 int right)

Uses an unnamed lambda parameter to show that one argument is intentionally ignored.

Parameters:

left - the useful value

right - ignored value

Returns:

a computed value based only on the first argument

countValues

public int countValues(Iterable<String> values)

Uses unnamed variables in a loop when only iteration count matters.

Parameters:

values - values to iterate over

Returns:

count of values

broadType

public String broadType(Object value)

Uses an unnamed pattern variable in a switch pattern.

Parameters:

value - the value to classify

Returns:

a broad type label