New recipe to adopt Lombok setter method names

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

@@ -0,0 +1,144 @@
+/*
+ * 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.lombok;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.ScanningRecipe;
+import org.openrewrite.Tree;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.ChangeMethodName;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.JavaType;
+import org.openrewrite.java.tree.TypeUtils;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class AdoptLombokSetterMethodNames extends ScanningRecipe<List<AdoptLombokSetterMethodNames.RenameRecord>> {
+
+    private final static String DO_NOT_RENAME = "DO_NOT_RENAME";
+
+    @Override
+    public String getDisplayName() {
+        return "Rename setter methods to fit Lombok";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Rename methods that are effectively setter to the name Lombok would give them.\n" +
+                "Limitations:\n" +
+                " - If two methods in a class are effectively the same setter then one's name will be corrected and the others name will be left as it is.\n" +
+                " - If the correct name for a method is already taken by another method then the name will not be corrected.\n" +
+                " - Method name swaps or circular renaming within a class cannot be performed because the names block each other.\n " +
+                "E.g. `int getFoo() { return ba; } int getBa() { return foo; }` stays as it is.";
+    }
+
+    @Value
+    public static class RenameRecord {
+        String methodPattern;
+        String newMethodName;
+    }
+
+    @Override
+    public List<RenameRecord> getInitialValue(ExecutionContext ctx) {
+        return new ArrayList<>();
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getScanner(List<RenameRecord> renameRecords) {
+        return new JavaIsoVisitor<ExecutionContext>() {
+            @Override
+            public J.CompilationUnit visitCompilationUnit(J.CompilationUnit cu, ExecutionContext ctx) {
+                // Cheaply collect all declared methods; this also means we do not support clashing nested class methods
+                Set<JavaType.Method> declaredMethods = cu.getTypesInUse().getDeclaredMethods();
+                List<String> existingMethodNames = new ArrayList<>();
+                for (JavaType.Method method : declaredMethods) {
+                    existingMethodNames.add(method.getName());
+                }
+                getCursor().putMessage(DO_NOT_RENAME, existingMethodNames);
+                return super.visitCompilationUnit(cu, ctx);
+            }
+
+            @Override
+            public J.MethodDeclaration visitMethodDeclaration(J.MethodDeclaration method, ExecutionContext ctx) {
+                if (method.getMethodType() == null || method.getBody() == null ||
+                        !LombokUtils.isEffectivelySetter(method) ||
+                        TypeUtils.isOverride(method.getMethodType())) {
+                    return method;
+                }
+
+                JavaType.Variable fieldType = extractVariable(method);
+
+                String expectedMethodName = LombokUtils.deriveSetterMethodName(fieldType);
+                // If method already has the name it should have, then nothing to be done
+                if (expectedMethodName.equals(method.getSimpleName())) {
+                    return method;
+                }
+
+                // If the desired method name is already taken by an existing method, the current method cannot be renamed
+                List<String> doNotRename = getCursor().getNearestMessage(DO_NOT_RENAME);
+                assert doNotRename != null;
+                if (doNotRename.contains(expectedMethodName)) {
+                    return method;
+                }
+
+                renameRecords.add(new RenameRecord(MethodMatcher.methodPattern(method), expectedMethodName));
+                doNotRename.remove(method.getSimpleName()); //actual method name becomes available again
+                doNotRename.add(expectedMethodName); //expected method name now blocked
+                return method;
+            }
+
+            private JavaType.@Nullable Variable extractVariable(J.MethodDeclaration method) {
+                J.Assignment assignment_ = (J.Assignment) method.getBody().getStatements().get(0);
+
+                JavaType.Variable fieldType;
+                if (assignment_.getVariable() instanceof J.FieldAccess) {
+                    J.FieldAccess fieldAccess = (J.FieldAccess) assignment_.getVariable();
+                    fieldType = fieldAccess.getName().getFieldType();
+                } else if (assignment_.getVariable() instanceof J.Identifier) {
+                    J.Identifier fieldAccess = (J.Identifier) assignment_.getVariable();
+                    fieldType = fieldAccess.getFieldType();
+                } else {
+                    //only those types above are possible, see LombokUtils::isEffectivelySetter
+                    throw new IllegalStateException("Unexpected type for returned variable");
+                }
+                return fieldType;
+            }
+        };
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor(List<RenameRecord> renameRecords) {
+        return new TreeVisitor<Tree, ExecutionContext>() {
+            @Override
+            public @Nullable Tree visit(@Nullable Tree tree, ExecutionContext ctx) {
+                for (RenameRecord rr : renameRecords) {
+                    tree = new ChangeMethodName(rr.methodPattern, rr.newMethodName, true, null)
+                            .getVisitor().visit(tree, ctx);
+                }
+                return tree;
+            }
+        };
+    }
+}

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

@@ -24,8 +24,10 @@
 import org.openrewrite.java.tree.Expression;
 import org.openrewrite.java.tree.J;
 import org.openrewrite.java.tree.JavaType;
+import org.openrewrite.java.tree.Statement;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 import static lombok.AccessLevel.*;
 import static org.openrewrite.java.tree.J.Modifier.Type.*;
@@ -173,6 +175,41 @@ private static boolean hasMatchingSetterMethodName(J.MethodDeclaration method, S
         return method.getSimpleName().equals("set" + StringUtils.capitalize(simpleName));
     }
 
+    public static boolean isEffectivelySetter(J.MethodDeclaration method) {
+        boolean isVoid = "void".equals(method.getType().toString());
+        List<Statement> actualParameters = method.getParameters().stream()
+                .filter(s -> !(s instanceof J.Empty))
+                .collect(Collectors.toList());
+        boolean oneParam = actualParameters.size() == 1;
+        if (!isVoid || !oneParam)
+            return false;
+
+        J.VariableDeclarations variableDeclarations = (J.VariableDeclarations) actualParameters.get(0);
+        J.VariableDeclarations.NamedVariable param = variableDeclarations.getVariables().get(0);
+        String paramName = param.getName().toString();
+
+        if (method.getBody() == null ||
+                method.getBody().getStatements().size() != 1 ||
+                !(method.getBody().getStatements().get(0) instanceof J.Assignment)) {
+            return false;
+        }
+        J.Assignment assignment = (J.Assignment) method.getBody().getStatements().get(0);
+
+        if (!(assignment.getVariable() instanceof J.FieldAccess) && !(assignment.getVariable() instanceof J.Identifier)) {
+            return false;
+        }
+
+        JavaType fieldType = assignment.getVariable().getType();
+        // assigned value is exactly the parameter
+        return assignment.getAssignment().toString().equals(paramName) &&
+                        param.getType() != null &&
+                        param.getType().equals(fieldType);  // type of parameter and field have to match
+    }
+
+    public static String deriveSetterMethodName(JavaType.Variable fieldType) {
+        return "set" + StringUtils.capitalize(fieldType.getName());
+    }
+
     static AccessLevel getAccessLevel(J.MethodDeclaration methodDeclaration) {
         if (methodDeclaration.hasModifier(Public)) {
             return PUBLIC;