Add a ScopedVariable trait

src/main/java/org/openrewrite/java/migrate/trait/ScopedVariable.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2024 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.migrate.trait;
+
+import lombok.RequiredArgsConstructor;
+import lombok.Value;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.Cursor;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.trait.SimpleTraitMatcher;
+import org.openrewrite.trait.Trait;
+
+@Value
+public class ScopedVariable implements Trait<J.VariableDeclarations.NamedVariable> {
+    Cursor cursor;
+    Cursor scope;
+    J.Identifier identifier;
+
+    @RequiredArgsConstructor
+    public static class Matcher extends SimpleTraitMatcher<ScopedVariable> {
+
+        @Override
+        protected @Nullable ScopedVariable test(Cursor cursor) {
+            if (cursor.getValue() instanceof J.VariableDeclarations.NamedVariable) {
+                J.VariableDeclarations.NamedVariable variable = cursor.getValue();
+                return new ScopedVariable(cursor, variable.getDeclaringScope(cursor), variable.getName());
+            }
+            return null;
+        }
+    }
+}

src/main/java/org/openrewrite/java/migrate/trait/package-info.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2024 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.
+ */
+@NullMarked
+@NonNullFields
+package org.openrewrite.java.migrate.trait;
+
+import org.jspecify.annotations.NullMarked;
+import org.openrewrite.internal.lang.NonNullFields;

src/test/java/org/openrewrite/java/migrate/trait/ScopedVariableTest.java

@@ -0,0 +1,96 @@
+/*
+ * Copyright 2024 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.migrate.trait;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.InMemoryExecutionContext;
+import org.openrewrite.Recipe;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.marker.SearchResult;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.openrewrite.java.Assertions.java;
+
+class ScopedVariableTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(RewriteTest.toRecipe(() ->
+          new ScopedVariable.Matcher().asVisitor(a -> SearchResult.found(a.getTree(),
+              String.format("Identified variable %s within scope %s", a.getIdentifier(), a.getScope().getValue().getClass().getSimpleName())
+            )
+          )
+        ));
+    }
+
+    @Test
+    @DocumentExample
+    void markAllFieldsInClass() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              class Test {
+                  private String field;
+
+                  void doSome() {
+                      String anotherField;
+                  }
+              }
+              """,
+            """
+              class Test {
+                  private String /*~~(Identified variable field within scope Block)~~>*/field;
+
+                  void doSome() {
+                      String /*~~(Identified variable anotherField within scope Block)~~>*/anotherField;
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void markAllFieldsInMethod() {
+        rewriteRun(
+          spec -> spec.recipe(Recipe.noop()),
+          //language=java
+          java(
+            """
+              class Test {
+                  private String field;
+
+                  void doSome() {
+                      String anotherField;
+                  }
+              }
+              """,
+            spec -> spec.beforeRecipe((source) -> {
+                J.MethodDeclaration md = (J.MethodDeclaration) source.getClasses().get(0).getBody().getStatements().get(1);
+                new ScopedVariable.Matcher().asVisitor(var -> {
+                    assertThat(((J.Block) var.getScope().getValue())).isEqualTo(md.getBody());
+                    return var.getTree();
+                }).visit(md, new InMemoryExecutionContext());
+            })
+          )
+        );
+    }
+
+}