Adopt SequencedCollection First and Last methods (#339)

* Adopt SequencedCollection First and Last methods

* Add license header

* First passing tests when running on Java 21

* Add negative tests and simplify condition

* Add IteratorNext recipe that only transforms sequenced collections

* Limit recipes to running on Java 21

* Do not use `addLast` as the index is off by one

* Use correct method type on getFirst

* Use correct return type and declaring type

* Drop JavaTemplate as template was context sensitive

* Drop afterTypeValidationOptions by adding rewrite-java-21

* More descriptive test names

* Document improbable comment loss

build.gradle.kts

@@ -38,6 +38,7 @@ dependencies {
     runtimeOnly("org.openrewrite:rewrite-java-8")
     runtimeOnly("org.openrewrite:rewrite-java-11")
     runtimeOnly("org.openrewrite:rewrite-java-17")
+    runtimeOnly("org.openrewrite:rewrite-java-21")
 
     testImplementation("org.junit.jupiter:junit-jupiter-api:latest.release")
     testImplementation("org.junit.jupiter:junit-jupiter-params:latest.release")

src/main/java/org/openrewrite/java/migrate/util/IteratorNext.java

@@ -0,0 +1,74 @@
+/*
+ * 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.java.migrate.util;
+
+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.MethodMatcher;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.Expression;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.TypeUtils;
+
+public class IteratorNext extends Recipe {
+    private static final MethodMatcher ITERATOR_MATCHER = new MethodMatcher("java.util.Collection iterator()", true);
+    private static final MethodMatcher NEXT_MATCHER = new MethodMatcher("java.util.Iterator next()", true);
+
+    @Override
+    public String getDisplayName() {
+        return "Replace `iterator().next()` with `getFirst()`";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Replace `SequencedCollection.iterator().next()` with `getFirst()`.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(
+                Preconditions.and(
+                        new UsesJavaVersion<>(21),
+                        Preconditions.and(
+                                new UsesMethod<>(ITERATOR_MATCHER),
+                                new UsesMethod<>(NEXT_MATCHER)
+                        )
+                ),
+                new JavaIsoVisitor<ExecutionContext>() {
+                    @Override
+                    public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, ExecutionContext executionContext) {
+                        J.MethodInvocation nextInvocation = super.visitMethodInvocation(method, executionContext);
+                        if (NEXT_MATCHER.matches(nextInvocation) && ITERATOR_MATCHER.matches(nextInvocation.getSelect())) {
+                            J.MethodInvocation iteratorInvocation = (J.MethodInvocation) nextInvocation.getSelect();
+                            if (TypeUtils.isAssignableTo("java.util.SequencedCollection", iteratorInvocation.getSelect().getType())) {
+                                J.MethodInvocation getFirstInvocation = nextInvocation.withSelect(iteratorInvocation.getSelect())
+                                        .withName(nextInvocation.getName().withSimpleName("getFirst"))
+                                        .withMethodType(nextInvocation.getMethodType()
+                                                .withName("getFirst")
+                                                .withDeclaringType(iteratorInvocation.getMethodType().getDeclaringType()));
+                                return getFirstInvocation;
+                            }
+                        }
+                        return nextInvocation;
+                    }
+                }
+        );
+    }
+}

src/main/java/org/openrewrite/java/migrate/util/ListFirstAndLast.java

@@ -0,0 +1,137 @@
+/*
+ * 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.java.migrate.util;
+
+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.MethodMatcher;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.search.UsesMethod;
+import org.openrewrite.java.tree.Expression;
+import org.openrewrite.java.tree.J;
+import org.openrewrite.java.tree.JavaType;
+import org.openrewrite.java.tree.Space;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+public class ListFirstAndLast extends Recipe {
+
+    private static final MethodMatcher ADD_MATCHER = new MethodMatcher("java.util.List add(int, ..)", true); // , * fails
+    private static final MethodMatcher GET_MATCHER = new MethodMatcher("java.util.List get(int)", true);
+    private static final MethodMatcher REMOVE_MATCHER = new MethodMatcher("java.util.List remove(int)", true);
+    private static final MethodMatcher SIZE_MATCHER = new MethodMatcher("java.util.List size()", true);
+
+    @Override
+    public String getDisplayName() {
+        return "Replace `List` `get`, `add`, and `remove` with `SequencedCollection` `*First` and `*Last` methods";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Replace `list.get(0)` with `list.getFirst()`, `list.get(list.size() - 1)` with `list.getLast()`, and similar for `add(int, E)` and `remove(int)`.";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return Preconditions.check(
+                Preconditions.and(
+                        new UsesJavaVersion<>(21),
+                        Preconditions.or(
+                                new UsesMethod<>(ADD_MATCHER),
+                                new UsesMethod<>(GET_MATCHER),
+                                new UsesMethod<>(REMOVE_MATCHER)
+                        )
+                ),
+                new FirstLastVisitor());
+    }
+
+    private static class FirstLastVisitor extends JavaIsoVisitor<ExecutionContext> {
+        @Override
+        public J.MethodInvocation visitMethodInvocation(J.MethodInvocation method, ExecutionContext executionContext) {
+            J.MethodInvocation mi = super.visitMethodInvocation(method, executionContext);
+            Expression select = mi.getSelect();
+            if (!(select instanceof J.Identifier)) {
+                return mi;
+            }
+            J.Identifier sequencedCollection = (J.Identifier) select;
+
+            final String operation;
+            if (ADD_MATCHER.matches(mi)) {
+                operation = "add";
+            } else if (GET_MATCHER.matches(mi)) {
+                operation = "get";
+            } else if (REMOVE_MATCHER.matches(mi)) {
+                operation = "remove";
+            } else {
+                return mi;
+            }
+
+            final String firstOrLast;
+            Expression expression = mi.getArguments().get(0);
+            if (J.Literal.isLiteralValue(expression, 0)) {
+                firstOrLast = "First";
+            } else if (!"add".equals(operation) && lastElementOfSequencedCollection(sequencedCollection, expression)) {
+                firstOrLast = "Last";
+            } else {
+                return mi;
+            }
+
+            List<Expression> arguments = new ArrayList<>();
+            final JavaType.Method newMethodType;
+            JavaType.Method originalMethodType = mi.getMethodType();
+            if ("add".equals(operation)) {
+                arguments.add(mi.getArguments().get(1).withPrefix(Space.EMPTY));
+                newMethodType = originalMethodType
+                        .withName(operation + firstOrLast)
+                        .withParameterNames(Collections.singletonList(originalMethodType.getParameterNames().get(1)))
+                        .withParameterTypes(Collections.singletonList(originalMethodType.getParameterTypes().get(1)));
+            } else {
+                newMethodType = originalMethodType
+                        .withName(operation + firstOrLast)
+                        .withParameterNames(null)
+                        .withParameterTypes(null);
+            }
+            return mi.withName(mi.getName().withSimpleName(operation + firstOrLast))
+                    .withArguments(arguments)
+                    .withMethodType(newMethodType);
+        }
+
+        /**
+         * @param sequencedCollection the identifier of the collection we're calling `get` on
+         * @param expression          the expression we're passing to `get`
+         * @return true, if we're calling `sequencedCollection.size() - 1` in expression on the same collection
+         */
+        private static boolean lastElementOfSequencedCollection(J.Identifier sequencedCollection, Expression expression) {
+            if (expression instanceof J.Binary) {
+                J.Binary binary = (J.Binary) expression;
+                if (binary.getOperator() == J.Binary.Type.Subtraction
+                        && J.Literal.isLiteralValue(binary.getRight(), 1)
+                        && SIZE_MATCHER.matches(binary.getLeft())) {
+                    Expression sizeSelect = ((J.MethodInvocation) binary.getLeft()).getSelect();
+                    if (sizeSelect instanceof J.Identifier) {
+                        return sequencedCollection.getSimpleName().equals(((J.Identifier) sizeSelect).getSimpleName());
+                    }
+                }
+            }
+            return false;
+        }
+    }
+}

src/main/resources/META-INF/rewrite/java-version-21.yml

@@ -54,10 +54,9 @@ tags:
   - java21
   - collections
 recipeList:
+  - org.openrewrite.java.migrate.util.FirstAndLast
+  - org.openrewrite.java.migrate.util.IteratorNext
   # Iterator
-  - org.openrewrite.java.SimplifyMethodChain:
-      methodPatternChain: [ 'java.util.SequencedCollection iterator()', 'java.util.Iterator next()' ]
-      newMethodName: getFirst
   - org.openrewrite.java.ChangeMethodName:
       methodPattern: java.util.SortedSet first()
       newMethodName: getFirst
@@ -68,11 +67,5 @@ recipeList:
       methodPattern: java.util.NavigableSet descendingSet()
       newMethodName: reversed
   # TODO convert additional patterns to sequenced collections
-  # SequencedCollection.get(0) -> SequencedCollection.getFirst()
-  # SequencedCollection.get(SequencedCollection.size() - 1) -> SequencedCollection.getLast()
-  # list.add(0, E) -> SequencedCollection.addFirst(E)
-  # list.addLast(list.size(), E) -> SequencedCollection.addLast(E)
-  # list.remove(0) -> SequencedCollection.removeFirst()
-  # list.remove(list.size() - 1) -> SequencedCollection.removeLast()
   # list.listIterator() -> ???
   # list.listIterator(int) -> ???

src/test/java/org/openrewrite/java/migrate/util/IteratorNextTest.java

@@ -0,0 +1,144 @@
+/*
+ * 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.java.migrate.util;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.condition.EnabledForJreRange;
+import org.junit.jupiter.api.condition.JRE;
+import org.openrewrite.Issue;
+import org.openrewrite.test.RecipeSpec;
+import org.openrewrite.test.RewriteTest;
+
+import static org.openrewrite.java.Assertions.java;
+import static org.openrewrite.java.Assertions.javaVersion;
+
+@Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/243")
+@EnabledForJreRange(min = JRE.JAVA_21)
+class IteratorNextTest implements RewriteTest {
+    @Override
+    public void defaults(RecipeSpec spec) {
+        spec.recipe(new IteratorNext())
+          .allSources(src -> src.markers(javaVersion(21)));
+    }
+
+    @Test
+    void listIteratorNextToGetFirst() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.*;
+                            
+              class Foo {
+                  String bar(List<String> collection) {
+                      return collection.iterator().next();
+                  }
+              }
+              """,
+            """
+              import java.util.*;
+                            
+              class Foo {
+                  String bar(List<String> collection) {
+                      return collection.getFirst();
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void nonSequencedCollectionUnchanged() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.*;
+                  
+              class Foo {
+                  void bar(Collection<String> collection) {
+                      String first = collection.iterator().next();
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void nextCommentRetained() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.*;
+                  
+              class Foo {
+                  void bar(List<String> collection) {
+                      String first = collection
+                        .iterator()
+                        // Next comment
+                        .next();
+                  }
+              }
+              """,
+            """
+              import java.util.*;
+                  
+              class Foo {
+                  void bar(List<String> collection) {
+                      String first = collection
+                        // Next comment
+                        .getFirst();
+                  }
+              }
+              """
+          )
+        );
+    }
+
+    @Test
+    void iteratorCommentLost() {
+        rewriteRun(
+          //language=java
+          java(
+            """
+              import java.util.*;
+                  
+              class Foo {
+                  void bar(List<String> collection) {
+                      String first = collection
+                        // Iterator comment
+                        .iterator()
+                        .next();
+                  }
+              }
+              """,
+            """
+              import java.util.List;
+                  
+              class Foo {
+                  void bar(List<String> collection) {
+                      String first = collection
+                        .getFirst();
+                  }
+              }
+              """
+          )
+        );
+    }
+}