feat: convert any equals and hashcode to the lombok annotation, ignore implementation

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

@@ -0,0 +1,100 @@
+/*
+ * 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.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.JavaParser;
+import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.tree.J;
+
+import static java.util.Comparator.comparing;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class NegligentlyConvertEquals extends Recipe {
+
+    @Override
+    public String getDisplayName() {
+        //language=markdown
+        return "Replace any custom `equals` or `hashCode` methods with the `EqualsAndHashCode` annotation";
+    }
+
+    @Override
+    public String getDescription() {
+        //language=markdown
+        return "This recipe substitutes a class level `@EqualsAndHashCode` annotation for a custom `equals` or `hashCode` methods. " +
+                "If both are defined, then both will be replaced. If only one is defined then it will be replaced. " +
+                "This recipe does not check if the custom `equals` or `hashCode` methods behave like ones generated by the lombok annotation. " +
+                "Doing so is considered infeasible at this time. " +
+                "As a compromise this recipe finds and replaces the custom methods and relies on the user to review the changes closely. " +
+                "As a consequence this recipe is VERY DANGEROUS to include into a composite recipe! " +
+                "Users are advised to run it only in isolation.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return new Converter();
+    }
+
+    @Value
+    @EqualsAndHashCode(callSuper = false)
+    private static class Converter extends JavaIsoVisitor<ExecutionContext> {
+
+        MethodMatcher equalsMatcher = new MethodMatcher("* equals(Object)");
+        MethodMatcher hashCodeMatcher = new MethodMatcher("* hashCode()");
+
+        @Override
+        public J.ClassDeclaration visitClassDeclaration(J.ClassDeclaration classDecl, ExecutionContext ctx) {
+
+            J.ClassDeclaration classDeclAfterVisit = super.visitClassDeclaration(classDecl, ctx);
+
+            //only thing that can have changed is removal of either equals or hash code
+            //and something needs to have changed before we add an annotation at class level
+            if (classDeclAfterVisit != classDecl) {
+                maybeAddImport("lombok.EqualsAndHashCode");
+
+                //Add annotation
+                JavaTemplate template = JavaTemplate.builder("@EqualsAndHashCode\n")
+                        .imports("lombok.EqualsAndHashCode")
+                        .javaParser(JavaParser.fromJavaVersion().classpath("lombok"))
+                        .build();
+
+                return template.apply(
+                        updateCursor(classDeclAfterVisit),
+                        classDeclAfterVisit.getCoordinates().addAnnotation(comparing(J.Annotation::getSimpleName)));
+            }
+            return classDecl;
+        }
+
+        @Override
+        public J.@Nullable MethodDeclaration visitMethodDeclaration(J.MethodDeclaration method, ExecutionContext ctx) {
+            J.ClassDeclaration classDecl = getCursor().firstEnclosingOrThrow(J.ClassDeclaration.class);
+
+            // The enclosing class of a J.MethodDeclaration must be known for a MethodMatcher to match it
+            if (equalsMatcher.matches(method, classDecl) || hashCodeMatcher.matches(method, classDecl)) {
+                return null;
+            }
+            return method;
+        }
+    }
+}

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

@@ -0,0 +1,181 @@
+/*
+ * 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 org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+import org.openrewrite.java.JavaParser;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+
+class NegligentlyConvertEqualsTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new NegligentlyConvertEquals())
+          .parser(JavaParser.fromJavaVersion().logCompilationWarningsAndErrors(true).classpath("lombok"));
+    }
+
+    @DocumentExample
+    @Test
+    void replaceEquals() {
+        rewriteRun(// language=java
+          java(
+            """
+              class A {
+
+                  int foo;
+
+                  @Override
+                  public boolean equals(Object o) {
+                      return false;
+                  }
+              }
+              """,
+            """
+              import lombok.EqualsAndHashCode;
+
+              @EqualsAndHashCode
+              class A {
+
+                  int foo;
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void noCostomMethodsNoAnnotation() {
+        rewriteRun(// language=java
+          java(
+            """
+              class A {
+
+                  int foo;
+
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceEqualsInPackage() {
+        rewriteRun(// language=java
+          java(
+            """
+              package com.example;
+
+              class A {
+
+                  int foo;
+
+                  @Override
+                  public boolean equals(Object o) {
+                      return false;
+                  }
+              }
+              """,
+            """
+              package com.example;
+
+              import lombok.EqualsAndHashCode;
+
+              @EqualsAndHashCode
+              class A {
+
+                  int foo;
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceHashCode() {
+        rewriteRun(// language=java
+          java(
+            """
+              package com.example;
+
+              class A {
+
+                  int foo;
+
+                  @Override
+                  public int hashCode() {
+                      return 6;
+                  }
+              }
+              """,
+            """
+              package com.example;
+
+              import lombok.EqualsAndHashCode;
+
+              @EqualsAndHashCode
+              class A {
+
+                  int foo;
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void replaceEqualsAndHashCode() {
+        rewriteRun(// language=java
+          java(
+            """
+              package com.example;
+
+              class A {
+
+                  int foo;
+
+                  @Override
+                  public boolean equals(Object o) {
+                      return false;
+                  }
+
+                  @Override
+                  public int hashCode() {
+                      return 6;
+                  }
+
+              }
+              """,
+            """
+              package com.example;
+
+              import lombok.EqualsAndHashCode;
+
+              @EqualsAndHashCode
+              class A {
+
+                  int foo;
+
+              }
+              """
+          )
+        );
+    }
+
+}