[java] Support Records with Java 15 Preview

pmd-java/etc/grammar/Java.jjt

@@ -2,6 +2,7 @@
  * Remove support for Java 13 preview language features.
  * Promote text blocks as a permanent language features with Java 15.
  * Support Pattern Matching for instanceof with Java 15 Preview.
+ * Support Records with Java 15 Preview.
  * Andreas Dangel 08/2020
  *====================================================================
  * Add support for record types introduced as a preview language
@@ -419,7 +420,7 @@ public class JavaParser {
       throwParseException("With JDK 10, 'var' is a restricted local variable type and cannot be used for type declarations!");
     }
     if (jdkVersion >= 14 && preview && "record".equals(image)) {
-      throwParseException("With JDK 14 Preview, 'record' is a restricted identifier and cannot be used for type declarations!");
+      throwParseException("With JDK 14 Preview and JDK 15 Preview, 'record' is a restricted identifier and cannot be used for type declarations!");
     }
   }
   private void checkForMultipleCaseLabels() {
@@ -467,8 +468,8 @@ public class JavaParser {
   }
 
   private void checkForRecordType() {
-    if (jdkVersion != 14 || !preview) {
+    if (jdkVersion != 14 && jdkVersion != 15 || !preview) {
-      throwParseException("Records are only supported with Java 14 Preview");
+      throwParseException("Records are only supported with Java 14 Preview and Java 15 Preview");
     }
   }
 

pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/ASTRecordDeclaration.java

@@ -57,6 +57,12 @@ public final class ASTRecordDeclaration extends AbstractAnyTypeDeclaration {
         return isNested();
     }
 
+    @Override
+    public boolean isFinal() {
+        // A record is implicitly final
+        return true;
+    }
+
     /**
      * @deprecated Renamed to {@link #getRecordComponents()}
      */

pmd-java/src/test/java/net/sourceforge/pmd/lang/java/ast/Java15PreviewTest.java

@@ -7,10 +7,12 @@ package net.sourceforge.pmd.lang.java.ast;
 import java.util.List;
 
 import org.junit.Assert;
+import org.junit.Ignore;
 import org.junit.Test;
 
 import net.sourceforge.pmd.lang.ast.ParseException;
 import net.sourceforge.pmd.lang.java.JavaParsingHelper;
+import net.sourceforge.pmd.lang.java.ast.ASTAnyTypeBodyDeclaration.DeclarationKind;
 
 public class Java15PreviewTest {
     private final JavaParsingHelper java15p =
@@ -42,4 +44,113 @@ public class Java15PreviewTest {
         java15.parseResource("PatternMatchingInstanceof.java");
     }
 
+    @Test
+    public void recordPoint() {
+        ASTCompilationUnit compilationUnit = java15p.parseResource("Point.java");
+        ASTRecordDeclaration recordDecl = compilationUnit.getFirstDescendantOfType(ASTRecordDeclaration.class);
+        Assert.assertEquals("Point", recordDecl.getImage());
+        Assert.assertFalse(recordDecl.isNested());
+        Assert.assertTrue("Records are implicitly always final", recordDecl.isFinal());
+        List<ASTRecordComponent> components = recordDecl.getFirstChildOfType(ASTRecordComponentList.class)
+                                                        .findChildrenOfType(ASTRecordComponent.class);
+        Assert.assertEquals(2, components.size());
+        Assert.assertEquals("x", components.get(0).getVarId().getImage());
+        Assert.assertEquals("y", components.get(1).getVarId().getImage());
+        Assert.assertNull(components.get(0).getVarId().getNameDeclaration().getAccessNodeParent());
+        Assert.assertEquals(Integer.TYPE, components.get(0).getVarId().getNameDeclaration().getType());
+        Assert.assertEquals("int", components.get(0).getVarId().getNameDeclaration().getTypeImage());
+    }
+
+    @Test(expected = ParseException.class)
+    public void recordPointBeforeJava15PreviewShouldFail() {
+        java15.parseResource("Point.java");
+    }
+
+    @Test(expected = ParseException.class)
+    public void recordCtorWithThrowsShouldFail() {
+        java15p.parse("  record R {"
+                          + "   R throws IOException {}"
+                          + "  }");
+    }
+
+    @Test(expected = ParseException.class)
+    public void recordMustNotExtend() {
+        java15p.parse("record RecordEx(int x) extends Number { }");
+    }
+
+    @Test(expected = ParseException.class)
+    @Ignore("Should we check this?")
+    public void recordCannotBeAbstract() {
+        java15p.parse("abstract record RecordEx(int x) { }");
+    }
+
+    @Test(expected = ParseException.class)
+    @Ignore("Should we check this?")
+    public void recordCannotHaveInstanceFields() {
+        java15p.parse("record RecordFields(int x) { private int y = 1; }");
+    }
+
+    @Test
+    public void innerRecords() {
+        ASTCompilationUnit compilationUnit = java15p.parseResource("Records.java");
+        List<ASTRecordDeclaration> recordDecls = compilationUnit.findDescendantsOfType(ASTRecordDeclaration.class, true);
+        Assert.assertEquals(7, recordDecls.size());
+
+        ASTRecordDeclaration complex = recordDecls.get(0);
+        Assert.assertEquals("MyComplex", complex.getSimpleName());
+        Assert.assertTrue(complex.isNested());
+        Assert.assertEquals(0, getComponent(complex, 0).findChildrenOfType(ASTAnnotation.class).size());
+        Assert.assertEquals(1, getComponent(complex, 1).findChildrenOfType(ASTAnnotation.class).size());
+        Assert.assertEquals(2, complex.getDeclarations().size());
+        Assert.assertTrue(complex.getDeclarations().get(0).getChild(1) instanceof ASTConstructorDeclaration);
+        Assert.assertTrue(complex.getDeclarations().get(1).getChild(0) instanceof ASTRecordDeclaration);
+        Assert.assertTrue(complex.getParent() instanceof ASTClassOrInterfaceBodyDeclaration);
+        ASTClassOrInterfaceBodyDeclaration complexParent = complex.getFirstParentOfType(ASTClassOrInterfaceBodyDeclaration.class);
+        Assert.assertEquals(DeclarationKind.RECORD, complexParent.getKind());
+        Assert.assertSame(complex, complexParent.getDeclarationNode());
+
+        ASTRecordDeclaration nested = recordDecls.get(1);
+        Assert.assertEquals("Nested", nested.getSimpleName());
+        Assert.assertTrue(nested.isNested());
+
+        ASTRecordDeclaration range = recordDecls.get(2);
+        Assert.assertEquals("Range", range.getSimpleName());
+        Assert.assertEquals(2, range.getComponentList().size());
+        List<ASTRecordConstructorDeclaration> rangeConstructors = range.findDescendantsOfType(ASTRecordConstructorDeclaration.class);
+        Assert.assertEquals(1, rangeConstructors.size());
+        Assert.assertEquals("Range", rangeConstructors.get(0).getImage());
+        Assert.assertTrue(rangeConstructors.get(0).getChild(0) instanceof ASTAnnotation);
+        Assert.assertEquals(2, range.getDeclarations().size());
+
+        ASTRecordDeclaration varRec = recordDecls.get(3);
+        Assert.assertEquals("VarRec", varRec.getSimpleName());
+        Assert.assertEquals("x", getComponent(varRec, 0).getVarId().getImage());
+        Assert.assertTrue(getComponent(varRec, 0).isVarargs());
+        Assert.assertEquals(2, getComponent(varRec, 0).findChildrenOfType(ASTAnnotation.class).size());
+        Assert.assertEquals(1, getComponent(varRec, 0).getTypeNode().findDescendantsOfType(ASTAnnotation.class).size());
+
+        ASTRecordDeclaration arrayRec = recordDecls.get(4);
+        Assert.assertEquals("ArrayRec", arrayRec.getSimpleName());
+        Assert.assertEquals("x", getComponent(arrayRec, 0).getVarId().getImage());
+        Assert.assertTrue(getComponent(arrayRec, 0).getVarId().hasArrayType());
+
+        ASTRecordDeclaration emptyRec = recordDecls.get(5);
+        Assert.assertEquals("EmptyRec", emptyRec.getSimpleName());
+        Assert.assertEquals(0, emptyRec.getComponentList().size());
+
+        ASTRecordDeclaration personRec = recordDecls.get(6);
+        Assert.assertEquals("PersonRecord", personRec.getSimpleName());
+        ASTImplementsList impl = personRec.getFirstChildOfType(ASTImplementsList.class);
+        Assert.assertEquals(2, impl.findChildrenOfType(ASTClassOrInterfaceType.class).size());
+    }
+
+    private ASTRecordComponent getComponent(ASTRecordDeclaration arrayRec, int index) {
+        return (ASTRecordComponent) arrayRec.getComponentList().getChild(index);
+    }
+
+
+    @Test(expected = ParseException.class)
+    public void recordIsARestrictedIdentifier() {
+        java15p.parse("public class record {}");
+    }
 }

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/ast/jdkversiontests/java15p/Point.java

@@ -0,0 +1,10 @@
+/**
+ * @see <a href="https://openjdk.java.net/jeps/384">JEP 384: Records (Second Preview)</a>
+ */
+public record Point(int x, int y) {
+
+    public static void main(String[] args) {
+        Point p = new Point(1, 2);
+        System.out.println("p = " + p);
+    }
+}

pmd-java/src/test/resources/net/sourceforge/pmd/lang/java/ast/jdkversiontests/java15p/Records.java

@@ -0,0 +1,61 @@
+import java.io.IOException;
+import java.lang.annotation.Target;
+import java.lang.annotation.ElementType;
+
+/**
+ * @see <a href="https://openjdk.java.net/jeps/384">JEP 384: Records (Second Preview)</a>
+ */
+public class Records {
+
+    @Target(ElementType.TYPE_USE)
+    @interface Nullable { }
+
+    @Target({ElementType.CONSTRUCTOR, ElementType.PARAMETER})
+    @interface MyAnnotation { }
+
+    public record MyComplex(int real, @Deprecated int imaginary) {
+        // explicit declaration of a canonical constructor
+        @MyAnnotation
+        public MyComplex(@MyAnnotation int real, int imaginary) {
+            if (real > 100) throw new IllegalArgumentException("too big");
+            this.real = real;
+            this.imaginary = imaginary;
+        }
+        public record Nested(int a) {}
+    }
+
+
+    public record Range(int lo, int hi) {
+        // compact record constructor
+        @MyAnnotation
+        public Range {
+          if (lo > hi)  /* referring here to the implicit constructor parameters */
+            throw new IllegalArgumentException(String.format("(%d,%d)", lo, hi));
+        }
+
+        public void foo() { }
+    }
+
+    public record VarRec(@Nullable @Deprecated String @Nullable ... x) {}
+
+    public record ArrayRec(int x[]) {}
+
+    public record EmptyRec<Type>() {
+        public void foo() { }
+        public Type bar() { return null; }
+        public static void baz() {
+            EmptyRec<String> r = new EmptyRec<>();
+            System.out.println(r);
+        }
+    }
+
+    // see https://www.javaspecialists.eu/archive/Issue276.html
+    public interface Person {
+        String firstName();
+        String lastName();
+    }
+    public record PersonRecord(String firstName, String lastName)
+        implements Person, java.io.Serializable {
+
+    }
+}