Also handle field access

Author: timtebeek

src/main/java/org/openrewrite/java/migrate/lombok/LombokUtils.java

@@ -30,27 +30,33 @@
 
 class LombokUtils {
 
-    public static boolean isEffectivelyGetter(J.MethodDeclaration method) {
-        boolean takesNoParameters = method.getParameters().get(0) instanceof J.Empty;
-        boolean singularReturn = method.getBody() != null //abstract methods can be null
-                && method.getBody().getStatements().size() == 1 &&
-                method.getBody().getStatements().get(0) instanceof J.Return;
-
-        if (takesNoParameters && singularReturn) {
-            Expression returnExpression = ((J.Return) method.getBody().getStatements().get(0)).getExpression();
-            //returns just an identifier
-            if (returnExpression instanceof J.Identifier) {
-                J.Identifier identifier = (J.Identifier) returnExpression;
-                JavaType.Variable fieldType = identifier.getFieldType();
-                return method.getType().equals(fieldType.getType());
-            }
+    static boolean isEffectivelyGetter(J.MethodDeclaration method) {
+        // Check signature: no parameters
+        if (!(method.getParameters().get(0) instanceof J.Empty) || method.getReturnTypeExpression() == null) {
+            return false;
+        }
+        // Check body: just a return statement
+        if (method.getBody() == null ||
+                method.getBody().getStatements().size() != 1 ||
+                !(method.getBody().getStatements().get(0) instanceof J.Return)) {
+            return false;
+        }
+        Expression returnExpression = ((J.Return) method.getBody().getStatements().get(0)).getExpression();
+        //returns just an identifier
+        if (returnExpression instanceof J.Identifier) {
+            J.Identifier identifier = (J.Identifier) returnExpression;
+            JavaType.Variable fieldType = identifier.getFieldType();
+            return method.getType().equals(fieldType.getType());
+        } else if (returnExpression instanceof J.FieldAccess) {
+            J.FieldAccess fieldAccess = (J.FieldAccess) returnExpression;
+            JavaType fieldType = fieldAccess.getType();
+            return method.getType().equals(fieldType);
         }
         return false;
     }
 
-    public static String deriveGetterMethodName(JavaType.Variable fieldType) {
-        String fieldName = fieldType.getName();
-        if (fieldType.getType() == JavaType.Variable.Primitive.Boolean) {
+    static String deriveGetterMethodName(JavaType type, String fieldName) {
+        if (type == JavaType.Primitive.Boolean) {
             boolean alreadyStartsWithIs = fieldName.length() >= 3 &&
                     fieldName.substring(0, 3).matches("is[A-Z]");
             if (alreadyStartsWithIs) {
@@ -62,7 +68,7 @@ public static String deriveGetterMethodName(JavaType.Variable fieldType) {
         return "get" + StringUtils.capitalize(fieldName);
     }
 
-    public static AccessLevel getAccessLevel(Collection<J.Modifier> modifiers) {
+    static AccessLevel getAccessLevel(Collection<J.Modifier> modifiers) {
         Map<J.Modifier.Type, AccessLevel> map = ImmutableMap.<J.Modifier.Type, AccessLevel>builder()
                 .put(Public, PUBLIC)
                 .put(Protected, PROTECTED)

src/main/java/org/openrewrite/java/migrate/lombok/UseLombokGetter.java

@@ -25,6 +25,7 @@
 import org.openrewrite.java.JavaIsoVisitor;
 import org.openrewrite.java.JavaParser;
 import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.tree.Expression;
 import org.openrewrite.java.tree.J;
 
 import java.util.Collections;
@@ -92,12 +93,23 @@ public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, Ex
         public J.@Nullable MethodDeclaration visitMethodDeclaration(J.MethodDeclaration method, ExecutionContext ctx) {
             if (method.getMethodType() != null && LombokUtils.isEffectivelyGetter(method)) {
                 J.Return return_ = (J.Return) method.getBody().getStatements().get(0);
-                Variable fieldType = ((J.Identifier) return_.getExpression()).getFieldType();
-                boolean nameMatch = method.getSimpleName().equals(LombokUtils.deriveGetterMethodName(fieldType));
-                if (nameMatch) {
-                    ((Set<Finding>) getCursor().getNearestMessage(FIELDS_TO_DECORATE_KEY))
-                            .add(new Finding(fieldType.getName(), LombokUtils.getAccessLevel(method.getModifiers())));
-                    return null; //delete
+                Expression returnExpression = return_.getExpression();
+                if (returnExpression instanceof J.Identifier) {
+                    J.Identifier identifier = (J.Identifier) returnExpression;
+                    String deriveGetterMethodName = LombokUtils.deriveGetterMethodName(identifier.getType(), identifier.getSimpleName());
+                    if (method.getSimpleName().equals(deriveGetterMethodName)) {
+                        ((Set<Finding>) getCursor().getNearestMessage(FIELDS_TO_DECORATE_KEY))
+                                .add(new Finding(identifier.getSimpleName(), LombokUtils.getAccessLevel(method.getModifiers())));
+                        return null;
+                    }
+                } else if (returnExpression instanceof J.FieldAccess) {
+                    J.FieldAccess fieldAccess = (J.FieldAccess) returnExpression;
+                    String deriveGetterMethodName = LombokUtils.deriveGetterMethodName(fieldAccess.getType(), fieldAccess.getSimpleName());
+                    if (method.getSimpleName().equals(deriveGetterMethodName)) {
+                        ((Set<Finding>) getCursor().getNearestMessage(FIELDS_TO_DECORATE_KEY))
+                                .add(new Finding(fieldAccess.getSimpleName(), LombokUtils.getAccessLevel(method.getModifiers())));
+                        return null;
+                    }
                 }
             }
             return method;

src/test/java/org/openrewrite/java/migrate/lombok/UseLombokGetterTest.java

@@ -57,6 +57,33 @@ class A {
         );
     }
 
+    @Test
+    void replaceGetterWithFieldAccess() {
+        rewriteRun(// language=java
+          java(
+            """
+              class A {
+
+                  int foo = 9;
+
+                  public int getFoo() {
+                      return this.foo;
+                  }
+              }
+              """,
+            """
+              import lombok.Getter;
+
+              class A {
+
+                  @Getter
+                  int foo = 9;
+              }
+              """
+          )
+        );
+    }
+
     @Test
     void replacePackageGetter() {
         rewriteRun(// language=java