Add java22 samples from PMD

.github/workflows/build.yml

@@ -8,7 +8,7 @@ jobs:
  - uses: actions/setup-java@v3
  with:
  distribution: 'temurin'
- java-version: '21'
+ java-version: '22-ea'
  cache: 'maven'
  - name: Build with Maven
  run: ./mvnw --show-version --no-transfer-progress --errors --batch-mode package

pom.xml

@@ -7,11 +7,11 @@
  <packaging>jar</packaging>
 
  <properties>
- <maven.compiler.release>21</maven.compiler.release>
+ <maven.compiler.release>22</maven.compiler.release>
  <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  <!-- fixing the build timestamp of the jar so that the jar file only changes, if content changes.
  the actual timestamp is irrelevant. -->
- <project.build.outputTimestamp>2022-09-26T17:00:00Z</project.build.outputTimestamp>
+ <project.build.outputTimestamp>1980-01-01T12:00:00Z</project.build.outputTimestamp>
  </properties>
 
  <build>

src/main/java/net/sourceforge/pmd/java/regression/tests/java22/Jep456_UnamedPatternsAndVariables.java

@@ -0,0 +1,122 @@
+// SPDX-License-Identifier: BSD-3-Clause
+package net.sourceforge.pmd.java.regression.tests.java22;
+
+import java.util.ArrayDeque;
+import java.util.List;
+import java.util.Queue;
+import java.util.stream.Collectors;
+
+/**
+ * @see <a href="https://openjdk.org/jeps/443">JEP 443: Unnamed Patterns and Variables (Preview)</a> (Java 21)
+ * @see <a href="https://openjdk.org/jeps/456">JEP 456: Unnamed Variables & Patterns</a> (Java 22)
+ */
+class Jep456_UnamedPatternsAndVariables {
+ record Point(int x, int y) { }
+ enum Color { RED, GREEN, BLUE }
+ record ColoredPoint(Point p, Color c) { }
+
+ void unnamedPatterns1() {
+ ColoredPoint r = new ColoredPoint(new Point(3,4), Color.GREEN);
+
+ if (r instanceof ColoredPoint(Point p, Color _)) {
+ System.out.println(p.x() + " " + p.y());
+ }
+
+ if (r instanceof ColoredPoint(Point(int x, int y), _)) {
+ System.out.println(x + " " + y);
+ }
+ }
+
+ sealed abstract class Ball permits RedBall, BlueBall, GreenBall { }
+ final class RedBall extends Ball { }
+ final class BlueBall extends Ball { }
+ final class GreenBall extends Ball { }
+
+ record Box<T extends Ball>(T content) { }
+
+ void unnamedPatterns2() {
+ Box<? extends Ball> b = new Box<>(new RedBall());
+ switch (b) {
+ case Box(RedBall _) -> processBox(b);
+ case Box(BlueBall _) -> processBox(b);
+ case Box(GreenBall _) -> stopProcessing();
+ }
+
+ switch (b) {
+ case Box(RedBall _), Box(BlueBall _) -> processBox(b);
+ case Box(GreenBall _) -> stopProcessing();
+ case Box(_) -> pickAnotherBox();
+ }
+
+ int x = 42;
+ switch (b) {
+ // multiple patterns guarded by one guard
+ case Box(RedBall _), Box(BlueBall _) when x == 42 -> processBox(b);
+ case Box(_) -> pickAnotherBox();
+ }
+ }
+
+ private void processBox(Box<? extends Ball> b) {}
+ private void stopProcessing() {}
+ private void pickAnotherBox() {}
+
+ class Order {}
+ private static final int LIMIT = 10;
+ private int sideEffect() {
+ return 0;
+ }
+
+ void unnamedVariables(List<Order> orders) {
+ int total = 0;
+ for (Order _ : orders) {
+ if (total < LIMIT) {
+ total++;
+ }
+ }
+ System.out.println("total: " + total);
+
+ for (int i = 0, _ = sideEffect(); i < 10; i++) {
+ System.out.println(i);
+ }
+
+ Queue<Integer> q = new ArrayDeque<>(); // x1, y1, z1, x2, y2, z2 ..
+ while (q.size() >= 3) {
+ int x = q.remove();
+ int y = q.remove();
+ int _ = q.remove(); // z is unused
+ Point p = new Point(x, y);
+ }
+ while (q.size() >= 3) {
+ var x = q.remove();
+ var _ = q.remove();
+ var _ = q.remove();
+ Point p = new Point(x, 0);
+ }
+ }
+
+ static class ScopedContext implements AutoCloseable {
+ @Override
+ public void close() { }
+ public static ScopedContext acquire() {
+ return new ScopedContext();
+ }
+ }
+
+ void unusedVariables2() {
+ try (var _ = ScopedContext.acquire()) {
+ //... acquiredContext not used ...
+ }
+
+ String s = "123";
+ try {
+ int i = Integer.parseInt(s);
+ System.out.println(i);
+ } catch (NumberFormatException _) {
+ System.out.println("Bad number: " + s);
+ } catch (Exception _) {
+ System.out.println("error...");
+ }
+
+ List.of("a", "b").stream().collect(Collectors.toMap(String::toUpperCase, _ -> "NO_DATA"));
+ }
+}