ReplaceCollectToListWithToList

src/main/java/org/openrewrite/staticanalysis/ReplaceCollectToListWithToList.java

@@ -0,0 +1,92 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (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://docs.moderne.io/licensing/moderne-source-available-license
+ * <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.staticanalysis;
+
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.JavaVisitor;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.J;
+
+import java.time.Duration;
+
+/**
+ * Replaces Stream.collect(Collectors.toList()) with Stream.toList()
+ * <p>
+ * <a href="https://github.com/apache/maven/pull/2322">[POC] rewrite-maven-plugin: Introduce OpenRewrite by Moderne</a>
+ * <a href="https://github.com/apache/maven/pull/2277">Modernize codebase with Java improvements</a>
+ * <a href="https://github.com/apache/maven/pull/2277#pullrequestreview-2814419390">suppression request</a>
+ *
+ */
+public class ReplaceCollectToListWithToList extends Recipe {
+
+    private static final MethodMatcher COLLECT_TO_LIST = new MethodMatcher("java.util.stream.Stream collect(java.util.stream.Collector)");
+
+    @Override
+    public String getDisplayName() {
+        return "Replace `Stream.collect(collectors.toList())` with `Stream.toList()`";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Replace Java 11 `Stream.collect(Collectors.toList())` with Java 16+ `Stream.toList()` for more concise syntax and an unmodifiable return value.";
+    }
+
+    @Override
+    public Duration getEstimatedEffortPerOccurrence() {
+        return Duration.ofMinutes(1);
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(Preconditions.and(
+                        new UsesJavaVersion<>(16),
+                        new UsesMethod<>(COLLECT_TO_LIST)),
+                new JavaVisitor<ExecutionContext>() {
+
+                    private final JavaTemplate template = JavaTemplate
+                            .builder("#{any(java.util.stream.Stream)}.toList()")
+                            .build();
+
+                    @Override
+                    public J visitMethodInvocation(J.MethodInvocation method, ExecutionContext ctx) {
+                        J.MethodInvocation m = (J.MethodInvocation) super.visitMethodInvocation(method, ctx);
+
+                        if (COLLECT_TO_LIST.matches(m) && isCollectorsToList(m)) {
+                            maybeRemoveImport("java.util.stream.Collectors");
+                            return template.apply(
+                                    updateCursor(m),
+                                    m.getCoordinates().replace(),
+                                    m.getSelect()
+                            );
+                        }
+                        return m;
+                    }
+
+                    private boolean isCollectorsToList(J.MethodInvocation method) {
+                        return method.getArguments().get(0) instanceof J.MethodInvocation &&
+                                ((J.MethodInvocation) method.getArguments().get(0)).getSimpleName().equals("toList") &&
+                                ((J.MethodInvocation) method.getArguments().get(0)).getSelect() != null &&
+                                ((J.MethodInvocation) method.getArguments().get(0)).getSelect().toString().equals("Collectors");
+                    }
+                });
+    }
+}

src/test/java/org/openrewrite/staticanalysis/ReplaceCollectToListWithToListTest.java

@@ -0,0 +1,105 @@
+/*
+ * Copyright 2025 the original author or authors.
+ * <p>
+ * Licensed under the Moderne Source Available License (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://docs.moderne.io/licensing/moderne-source-available-license
+ * <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.staticanalysis;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+import static org.openrewrite.java.Assertions.version;
+
+class InvertReplaceCollectToListWithToListTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new ReplaceCollectToListWithToList());
+    }
+
+    @DocumentExample
+    @Test
+    void replacesCollectToList() {
+        rewriteRun(
+          version(
+            //language=java
+            java(
+              """
+                package com.example;
+
+                import java.util.stream.Collectors;
+                import java.util.stream.Stream;
+
+                class Example {
+                    public void test() {
+                        Stream.of().collect(Collectors.toList());
+                    }
+                }
+                """,
+              """
+                package com.example;
+
+                import java.util.stream.Stream;
+
+                class Example {
+                    public void test() {
+                        Stream.of().toList();
+                    }
+                }
+                """),
+            17));
+    }
+
+    @Test
+    void replacesCollectToListKeepImport() {
+        rewriteRun(
+          version(
+            //language=java
+            java(
+              """
+                package com.example;
+
+                import java.util.List;
+                import java.util.stream.Collector;
+                import java.util.stream.Collectors;
+                import java.util.stream.Stream;
+
+                class Example {
+                    public void test() {
+                        Collector<Object,?,List<Object>> list = Collectors.toList();
+                        Stream.of().collect(list);
+                        Stream.of().collect(Collectors.toList());
+                    }
+                }
+                """,
+              """
+                package com.example;
+
+                import java.util.List;
+                import java.util.stream.Collector;
+                import java.util.stream.Collectors;
+                import java.util.stream.Stream;
+
+                class Example {
+                    public void test() {
+                        Collector<Object,?,List<Object>> list = Collectors.toList();
+                        Stream.of().collect(list);
+                        Stream.of().toList();
+                    }
+                }
+                """),
+            17));
+    }
+}