Explicitly sorted streams should be collected to a LinkedHashSet to preserve order

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

@@ -0,0 +1,70 @@
+/*
+ * Copyright 2023 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.staticanalysis;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.JavaTemplate;
+import org.openrewrite.java.MethodMatcher;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.J;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class SortedSetStreamToLinkedHashSet extends Recipe {
+
+    @Override
+    public String getDisplayName() {
+        return "Sorted set stream should be collected to LinkedHashSet";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Correct 'set.stream().sorted().collect(Collectors.toSet())' to 'set.stream().sorted().collect(LinkedHashSet::new)'.";
+    }
+
+    private static final MethodMatcher STREAM_COLLECT_METHOD_MATCHER = new MethodMatcher("java.util.stream.Stream collect(java.util.stream.Collector)");
+    private static final MethodMatcher STREAM_SORTED_METHOD_MATCHER = new MethodMatcher("java.util.stream.Stream sorted()");
+    private static final MethodMatcher COLLECTORS_TO_SET_METHOD_MATCHER = new MethodMatcher("java.util.stream.Collectors toSet()");
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(new UsesMethod<>(COLLECTORS_TO_SET_METHOD_MATCHER), new JavaIsoVisitor<ExecutionContext>() {
+            private JavaTemplate template = JavaTemplate.builder("Collectors.toCollection(LinkedHashSet::new)")
+                    .imports("java.util.stream.Collectors", "java.util.LinkedHashSet")
+                    .build();
+
+            @Override
+            public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, ExecutionContext executionContext) {
+                J.MethodInvocation mi = super.visitMethodInvocation(method, executionContext);
+                if (STREAM_COLLECT_METHOD_MATCHER.matches(mi)
+                    && STREAM_SORTED_METHOD_MATCHER.matches(mi.getSelect())
+                    && COLLECTORS_TO_SET_METHOD_MATCHER.matches(mi.getArguments().get(0))) {
+                    maybeRemoveImport("java.util.stream.Collectors.toSet");
+                    maybeAddImport("java.util.LinkedHashSet");
+                    maybeAddImport("java.util.stream.Collectors");
+                    return template.apply(updateCursor(mi), mi.getCoordinates().replaceArguments());
+                }
+                return mi;
+            }
+        });
+    }
+}

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

@@ -0,0 +1,116 @@
+/*
+ * Copyright 2023 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.staticanalysis;
+
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+
+class SortedSetStreamToLinkedHashSetTest implements RewriteTest {
+
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new SortedSetStreamToLinkedHashSet());
+    }
+
+    @Test
+    void changeSortedSetStreamToLinkedHashSet() {
+        rewriteRun(
+          //language=java
+          java("""
+            import java.util.Set;
+            import java.util.stream.Collectors;
+
+            class A {
+              void method(Set<Integer> set) {
+                  Set<Integer> sorted = set.stream().sorted().collect(Collectors.toSet());
+              }
+            }
+            """, """
+            import java.util.LinkedHashSet;
+            import java.util.Set;
+            import java.util.stream.Collectors;
+
+            class A {
+              void method(Set<Integer> set) {
+                  Set<Integer> sorted = set.stream().sorted().collect(Collectors.toCollection(LinkedHashSet::new));
+              }
+            }
+            """));
+    }
+
+    @Test
+    void changeSortedSetStreamToLinkedHashSetStaticImport() {
+        rewriteRun(
+          //language=java
+          java("""
+            import java.util.Set;
+            import static java.util.stream.Collectors.toSet;
+
+            class A {
+              void method(Set<Integer> set) {
+                  Set<Integer> sorted = set.stream().sorted().collect(toSet());
+              }
+            }
+            """, """
+            import java.util.LinkedHashSet;
+            import java.util.Set;
+            import java.util.stream.Collectors;
+
+            class A {
+              void method(Set<Integer> set) {
+                  Set<Integer> sorted = set.stream().sorted().collect(Collectors.toCollection(LinkedHashSet::new));
+              }
+            }
+            """));
+    }
+
+    @Test
+    void ignoreCollectToLinkedHashSet() {
+        rewriteRun(
+          //language=java
+          java("""
+            import java.util.Set;
+            import java.util.LinkedHashSet;
+            import java.util.stream.Collectors;
+
+            class A {
+              void method(Set<Integer> set) {
+                  Set<Integer> sorted = set.stream().sorted().collect(Collectors.toCollection(LinkedHashSet::new));
+              }
+            }
+            """));
+    }
+
+    @Test
+    void ignoreCollectToList() {
+        rewriteRun(
+          //language=java
+          java("""
+            import java.util.List;
+            import java.util.stream.Collectors;
+
+            class A {
+              void method(Set<Integer> set) {
+                  List<Integer> sorted = set.stream().sorted().collect(Collectors.toList());
+              }
+            }
+            """));
+    }
+}