Java 17 instanceof pattern matching (fixes #2158)

Author: jkschneider

rewrite-java-11/src/main/java/org/openrewrite/java/isolated/ReloadableJava11ParserVisitor.java

@@ -712,6 +712,7 @@ public J visitInstanceOf(InstanceOfTree node, Space fmt) {
         return new J.InstanceOf(randomId(), fmt, Markers.EMPTY,
                 convert(node.getExpression(), t -> sourceBefore("instanceof")),
                 convert(node.getType()),
+                null,
                 typeMapping.type(node));
     }
 

rewrite-java-17/src/main/java/org/openrewrite/java/isolated/ReloadableJava17ParserVisitor.java

@@ -708,10 +708,14 @@ public J visitImport(ImportTree node, Space fmt) {
 
     @Override
     public J visitInstanceOf(InstanceOfTree node, Space fmt) {
+        JavaType type = typeMapping.type(node);
         return new J.InstanceOf(randomId(), fmt, Markers.EMPTY,
                 convert(node.getExpression(), t -> sourceBefore("instanceof")),
                 convert(node.getType()),
-                typeMapping.type(node));
+                node.getPattern() instanceof JCBindingPattern b ?
+                        new J.Identifier(randomId(), sourceBefore(b.getVariable().getName().toString()), Markers.EMPTY, b.getVariable().getName().toString(),
+                                type, null) : null,
+                type);
     }
 
     @Override

rewrite-java-17/src/test/java/org/openrewrite/java/cleanup/UseDiamondOperatorWithVarTest.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2022 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.openrewrite.java.cleanup;
 
 import org.junit.jupiter.api.Test;

rewrite-java-17/src/test/java/org/openrewrite/java/tree/InstanceOfTest.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright 2022 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.java.tree;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.java.JavaVisitor;
+import org.openrewrite.test.RewriteTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.openrewrite.java.Assertions.java;
+
+public class InstanceOfTest implements RewriteTest {
+
+    @Test
+    void patternMatch() {
+        rewriteRun(
+          java(
+            """
+                  import java.util.*;
+                  class Test {
+                    public void match(Collection<?> c) {
+                          if (c instanceof List l) {
+                              System.out.println("List");
+                          } else if (c instanceof Set s) {
+                              System.out.println("Set");
+                          }
+                      }
+                  }
+              """,
+            spec -> spec.afterRecipe(cu -> new JavaVisitor<Integer>() {
+                @Override
+                public J visitInstanceOf(J.InstanceOf instanceOf, Integer integer) {
+                    assertThat(instanceOf.getPattern()).isNotNull();
+                    return instanceOf;
+                }
+            }.visit(cu, 0))
+          )
+        );
+    }
+}

rewrite-java-8/src/main/java/org/openrewrite/java/ReloadableJava8ParserVisitor.java

@@ -710,6 +710,7 @@ public J visitInstanceOf(InstanceOfTree node, Space fmt) {
         return new J.InstanceOf(randomId(), fmt, Markers.EMPTY,
                 convert(node.getExpression(), t -> sourceBefore("instanceof")),
                 convert(node.getType()),
+                null,
                 typeMapping.type(node));
     }
 

rewrite-java/src/main/java/org/openrewrite/java/JavaPrinter.java

@@ -604,6 +604,7 @@ public J visitInstanceOf(InstanceOf instanceOf, PrintOutputCapture<P> p) {
         visitMarkers(instanceOf.getMarkers(), p);
         visitRightPadded(instanceOf.getPadding().getExpr(), JRightPadded.Location.INSTANCEOF, "instanceof", p);
         visit(instanceOf.getClazz(), p);
+        visit(instanceOf.getPattern(), p);
         return instanceOf;
     }
 

rewrite-java/src/main/java/org/openrewrite/java/JavaVisitor.java

@@ -682,6 +682,7 @@ public J visitInstanceOf(J.InstanceOf instanceOf, P p) {
         }
         i = i.getPadding().withExpr(visitRightPadded(i.getPadding().getExpr(), JRightPadded.Location.INSTANCEOF, p));
         i = i.withClazz(visitAndCast(i.getClazz(), p));
+        i = i.withPattern(visitAndCast(i.getPattern(), p));
         i = i.withType(visitType(i.getType(), p));
         return i;
     }

rewrite-java/src/main/java/org/openrewrite/java/tree/J.java

@@ -2527,6 +2527,11 @@ public InstanceOf withExpression(Expression expression) {
         @Getter
         J clazz;
 
+        @Nullable
+        @With
+        @Getter
+        J pattern;
+
         @With
         @Nullable
         @Getter
@@ -2571,7 +2576,7 @@ public JRightPadded<Expression> getExpr() {
             }
 
             public InstanceOf withExpr(JRightPadded<Expression> expression) {
-                return t.expression == expression ? t : new InstanceOf(t.id, t.prefix, t.markers, expression, t.clazz, t.type);
+                return t.expression == expression ? t : new InstanceOf(t.id, t.prefix, t.markers, expression, t.clazz, t.pattern, t.type);
             }
         }