+ * 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 + *
+ * https://docs.moderne.io/licensing/moderne-source-available-license + *
+ * 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.lang;
+
+import lombok.EqualsAndHashCode;
+import lombok.Value;
+import org.jspecify.annotations.Nullable;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Preconditions;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.internal.ListUtils;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.search.UsesJavaVersion;
+import org.openrewrite.java.tree.*;
+import org.openrewrite.marker.Markers;
+import org.openrewrite.staticanalysis.groovy.GroovyFileChecker;
+import org.openrewrite.staticanalysis.kotlin.KotlinFileChecker;
+
+import java.util.List;
+
+import static org.openrewrite.Tree.randomId;
+
+@Value
+@EqualsAndHashCode(callSuper = false)
+public class SwitchCaseReturnsToSwitchExpression extends Recipe {
+ @Override
+ public String getDisplayName() {
+ return "Convert switch cases where every case returns into a returned switch expression";
+ }
+
+ @Override
+ public String getDescription() {
+ return "Switch statements where each case returns a value can be converted to a switch expression that returns the value directly.";
+ }
+
+ @Override
+ public TreeVisitor getVisitor() {
+ TreeVisitor preconditions = Preconditions.and(
+ new UsesJavaVersion<>(14),
+ Preconditions.not(new KotlinFileChecker<>()),
+ Preconditions.not(new GroovyFileChecker<>())
+ );
+ return Preconditions.check(preconditions, new JavaIsoVisitor
+ * 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
+ *
+ * https://docs.moderne.io/licensing/moderne-source-available-license
+ *
+ * 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.lang;
+
+import org.junit.jupiter.api.Test;
+import org.openrewrite.DocumentExample;
+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;
+
+class SwitchCaseReturnsToSwitchExpressionTest implements RewriteTest {
+
+ @Override
+ public void defaults(RecipeSpec spec) {
+ spec.recipe(new SwitchCaseReturnsToSwitchExpression())
+ .allSources(s -> s.markers(javaVersion(17)));
+ }
+
+ @DocumentExample
+ @Issue("https://github.com/openrewrite/rewrite-migrate-java/issues/800")
+ @Test
+ void convertSimpleSwitchWithReturns() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String doFormat(String str) {
+ switch (str) {
+ case "foo": return "Foo";
+ case "bar": return "Bar";
+ case null, default: return "Other";
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ String doFormat(String str) {
+ return switch (str) {
+ case "foo" -> "Foo";
+ case "bar" -> "Bar";
+ case null, default -> "Other";
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void convertSimpleSwitchWithReturnsAfterOtherStatements() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String doFormat(String str) {
+ System.out.println("Formatting: " + str);
+ switch (str) {
+ case "foo": return "Foo";
+ case "bar": return "Bar";
+ case null, default: return "Other";
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ String doFormat(String str) {
+ System.out.println("Formatting: " + str);
+ return switch (str) {
+ case "foo" -> "Foo";
+ case "bar" -> "Bar";
+ case null, default -> "Other";
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void convertSwitchWithColonCases() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ int getValue(String str) {
+ switch (str) {
+ case "one":
+ return 1;
+ case "two":
+ return 2;
+ default:
+ return 0;
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ int getValue(String str) {
+ return switch (str) {
+ case "one" -> 1;
+ case "two" -> 2;
+ default -> 0;
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void convertSwitchWithBlocksContainingReturns() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String process(int value) {
+ switch (value) {
+ case 1: {
+ return "One";
+ }
+ case 2: {
+ return "Two";
+ }
+ default: {
+ return "Many";
+ }
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ String process(int value) {
+ return switch (value) {
+ case 1 -> "One";
+ case 2 -> "Two";
+ default -> "Many";
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void convertSwitchWithArrowCases() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String format(String str) {
+ switch (str) {
+ case "foo" -> { return "Foo"; }
+ case "bar" -> { return "Bar"; }
+ default -> { return "Other"; }
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ String format(String str) {
+ return switch (str) {
+ case "foo" -> "Foo";
+ case "bar" -> "Bar";
+ default -> "Other";
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void convertEnumSwitchThatIsExhaustive() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ enum Color { RED, GREEN, BLUE }
+
+ String colorName(Color color) {
+ switch (color) {
+ case RED: return "Red";
+ case GREEN: return "Green";
+ case BLUE: return "Blue";
+ }
+ }
+ }
+ """,
+ """
+ class Test {
+ enum Color { RED, GREEN, BLUE }
+
+ String colorName(Color color) {
+ return switch (color) {
+ case RED -> "Red";
+ case GREEN -> "Green";
+ case BLUE -> "Blue";
+ };
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotConvertWhenNotAllCasesReturn() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String process(String str) {
+ switch (str) {
+ case "foo":
+ return "Foo";
+ case "bar":
+ System.out.println("Bar case");
+ break;
+ default:
+ return "Other";
+ }
+ return "End";
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotConvertWhenNoDefaultAndNotExhaustive() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String format(String str) {
+ switch (str) {
+ case "foo": return "Foo";
+ case "bar": return "Bar";
+ }
+ return "Not found";
+ }
+ }
+ """
+ )
+ );
+ }
+
+ @Test
+ void doNotConvertIfNotOnlyStatementInBlock() {
+ rewriteRun(
+ //language=java
+ java(
+ """
+ class Test {
+ String process(String str) {
+ switch (str) {
+ case "foo":
+ System.out.println("Processing: " + str);
+ return "Foo";
+ case "bar": return "Bar";
+ default: return "Other";
+ }
+ }
+ }
+ """
+ )
+ );
+ }
+}