Add the first few Java 19 tests

For now, only the "pattern matching for switch" tests from previews 1
and 2 were adjusted to work in preview 3, because guarded patterns were
replaced by 'when' clauses in 'switch' blocks. Therefore, existing test
classes did not compile anymore and had to be replaced by syntactically
upgraded versions with content merged from preview 1 and 2 classes.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>

1 files changed, 172 insertions, 0 deletions

diff --git a/tests/features1919/java19/SwitchPatternPreview3OK.java b/tests/features1919/java19/SwitchPatternPreview3OK.java
new file mode 100644
index 000000000..7060ec0c2
--- /dev/null
+++ b/tests/features1919/java19/SwitchPatternPreview3OK.java
@@ -0,0 +1,172 @@
+import java.util.List;
+import java.util.Locale;
+
+/**
+ * Inspired by examples in https://openjdk.org/jeps/427
+ */
+public class SwitchPatternPreview3OK {
+  public static void main(String[] args) {
+
+    System.out.println(formatterPatternSwitch(null));
+    System.out.println(formatterPatternSwitch(123));
+    System.out.println(formatterPatternSwitch(999L));
+    System.out.println(formatterPatternSwitch(12.34));
+    System.out.println(formatterPatternSwitch("foo"));
+    System.out.println(formatterPatternSwitch(List.of(123, "foo", 999L, 12.34)));
+
+    System.out.println(testCircle(new Rectangle()));
+    System.out.println(testCircle(new Circle(5)));
+    System.out.println(testCircle(new Circle(6)));
+
+    System.out.println(testSealedCoverage(new A()));
+    System.out.println(testSealedCoverage(new B()));
+    System.out.println(testSealedCoverage(new C(5)));
+
+//    constantLabelMustAppearBeforePattern(-1);
+//    constantLabelMustAppearBeforePattern(0);
+//    constantLabelMustAppearBeforePattern(42);
+//    constantLabelMustAppearBeforePattern(-99);
+//    constantLabelMustAppearBeforePattern(Integer.valueOf(123));
+//    constantLabelMustAppearBeforePattern(null);
+
+    constantLabelMustAppearBeforePatternInteger(-1);
+    constantLabelMustAppearBeforePatternInteger(0);
+    constantLabelMustAppearBeforePatternInteger(42);
+    constantLabelMustAppearBeforePatternInteger(-99);
+    constantLabelMustAppearBeforePatternInteger(Integer.valueOf(123));
+    constantLabelMustAppearBeforePatternInteger(null);
+
+//    System.out.println(testGenericSealedExhaustive(new B<Integer>()));
+  }
+
+  static String formatterPatternSwitch(Object o) {
+    return switch (o) {
+      case null      -> "null";
+      case Integer i -> String.format("int %d", i);
+      case Long l    -> String.format("long %d", l);
+      case Double d  -> String.format(Locale.ENGLISH, "double %f", d);
+      case String s  -> String.format("String %s", s);
+      default        -> o.toString();
+    };
+  }
+
+  static class Shape {}
+  static class Rectangle extends Shape {}
+  static class Circle extends Shape {
+    private final double radius;
+    public Circle(double radius) { this.radius = radius; }
+    double calculateArea() { return Math.PI * radius * radius; }
+  }
+
+  static String testCircle(Shape s) {
+    return switch (s) {
+      case Circle c when (c.calculateArea() > 100) -> "Large circle";
+      case Circle c -> "Small circle";
+      default -> "Non-circle";
+    };
+  }
+
+  sealed interface S permits A, B, C {}
+  final static class A implements S {}
+  final static class B implements S {}
+  static record C(int i) implements S {}  // Implicitly final
+
+  static String testSealedCoverage(S s) {
+    return switch (s) {
+      case A a -> "Sealed sub-class A";
+      case B b -> "Sealed sub-class B";
+      case C c -> "Sealed sub-record C";
+    };
+  }
+
+  /**
+   * According to an example from JEP 420, this should work, but it does not, neither with Javac nor ECJ.
+   *
+   * See:
+   *   https://openjdk.java.net/jeps/420#1b--Dominance-of-pattern-labels
+   *   https://bugs.openjdk.java.net/browse/JDK-8273326
+   *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=579355
+   *
+   * TODO: reactivate when implemented or move to preview 3 with Java 19, Eclipse 4.24.
+   */
+  /*
+  static String constantLabelMustAppearBeforePattern(Object o) {
+    switch (o) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("special case:" + o);
+      case Integer i && i > 0 -> System.out.println("positive integer: " + o);
+      case Integer i -> System.out.println("other integer: " + o);
+      default -> System.out.println("non-integer: " + o);
+    }
+    return i == null ? "null" : i.toString();
+  }
+  */
+
+  static String constantLabelMustAppearBeforePatternInteger(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+      default -> System.out.println("other integer: " + i);
+    }
+    return i == null ? "null" : i.toString();
+  }
+
+  static void nullCanAppearAfterConstantLabel(Integer i) {
+    switch (i) {
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case null -> System.out.println("value unavailable: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+      default -> System.out.println("other integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforePattern(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      default -> System.out.println("other integer: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforeNull(Integer i) {
+    switch (i) {
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      default -> System.out.println("other integer: " + i);
+      case null -> System.out.println("value unavailable: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  static void defaultCanAppearBeforeConstantLabel(Integer i) {
+    switch (i) {
+      case null -> System.out.println("value unavailable: " + i);
+      default -> System.out.println("other integer: " + i);
+      case -1, 1 -> System.out.println("absolute value 1: " + i);
+      case Integer value when value > 0 -> System.out.println("positive integer: " + i);
+    }
+  }
+
+  /**
+   * According to an example from JEP 420, this should work, and it does with Javac, but not with ECJ.
+   *
+   * See:
+   *   https://openjdk.java.net/jeps/420#2--Exhaustiveness-of-switch-expressions-and-statements
+   *   https://bugs.eclipse.org/bugs/show_bug.cgi?id=579360
+   *
+   * TODO: reactivate when implemented or move to preview 3 with Java 19, Eclipse 4.24.
+   */
+  /*
+  sealed interface I<T> permits A, B {}
+  final static class A<X> implements I<String> {}
+  final static class B<Y> implements I<Y> {}
+
+  static int testGenericSealedExhaustive(I<Integer> i) {
+    return switch (i) {
+      // Exhaustive as no A case possible!
+      case B<Integer> bi -> 42;
+    };
+  }
+  */
+}