Add java21-features module: runnable demos and captured output for the ankurm.com java21-features article

2026-10-20 17:13:59 +00:00
parent 5a076c826f
commit c3cc57f482
33 changed files with 354 additions and 0 deletions
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+/** JEP 440 (final): deconstruct records in instanceof and switch, nested. */
+public class RecordPatternsDemo {
+    record Point(int x, int y) {}
+    record Line(Point from, Point to) {}
+    record Box<T>(T content) {}
+
+    static String describe(Object o) {
+        if (o instanceof Line(Point(var x1, var y1), Point(var x2, var y2)))
+            return "line from (" + x1 + "," + y1 + ") to (" + x2 + "," + y2 + ") length^2=" + ((x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1));
+        if (o instanceof Box<?>(String s)) return "box of String " + s;
+        if (o instanceof Box<?>(Integer i)) return "box of Integer " + i;
+        return "no match";
+    }
+    public static void main(String[] args) {
+        System.out.println(describe(new Line(new Point(0, 0), new Point(3, 4))));
+        System.out.println(describe(new Box<>("hi")));
+        System.out.println(describe(new Box<>(7)));
+        System.out.println(describe(new Box<>(2.5)));
+    }
+}