Issue #146: Add recipe for UnusedImports

README.md

@@ -175,7 +175,7 @@ This table tracks the auto-fix support status of OpenRewrite recipes for each Ch
 | 🔴     | [`ImportControl`](https://checkstyle.sourceforge.io/checks/imports/importcontrol.html#ImportControl)                       |                                                                                                                                                | Restructure imports per rules |
 | 🟢     | [`ImportOrder`](https://checkstyle.sourceforge.io/checks/imports/importorder.html#ImportOrder)                             | `TBD`                                                                                                                                                |                |
 | 🟢     | [`RedundantImport`](https://checkstyle.sourceforge.io/checks/imports/redundantimport.html#RedundantImport)                 | [`RedundantImport`](https://github.com/checkstyle/checkstyle-openrewrite-recipes/blob/main/src/main/java/org/checkstyle/autofix/recipe/RedundantImport.java) |                |
-| 🟢     | [`UnusedImports`](https://checkstyle.sourceforge.io/checks/imports/unusedimports.html#UnusedImports)                       | `TBD`                                                                                                                                                |                |
+| 🟢     | [`UnusedImports`](https://checkstyle.sourceforge.io/checks/imports/unusedimports.html#UnusedImports)                       | [`UnusedImports`](https://github.com/checkstyle/checkstyle-openrewrite-recipes/blob/main/src/main/java/org/checkstyle/autofix/recipe/UnusedImports.java) |                |
 
 
 ### Javadoc Comments

config/suppressions.xml

@@ -19,4 +19,5 @@
     <suppress checks="MissingNullCaseInSwitch" files="[\\/]src[\\/]main[\\/]java[\\/]org[\\/]checkstyle[\\/]autofix[\\/]recipe[\\/]NewlineAtEndOfFile\.java"/>
 
     <suppress checks="ImportControlCheck" files="[\\/]src[\\/]test[\\/]java[\\/]org[\\/]checkstyle[\\/]autofix[\\/]recipe[\\/]NumericalPrefixesInfixesSuffixesCharacterCaseTest\.java"/>
+    <suppress checks="ImportControlCheck" files="[\\/]src[\\/]test[\\/]java[\\/]org[\\/]checkstyle[\\/]autofix[\\/]recipe[\\/]UnusedImportsTest\.java"/>
 </suppressions>

src/main/java/org/checkstyle/autofix/CheckFullName.java

@@ -28,6 +28,7 @@ public enum CheckFullName {
     HEX_LITERAL_CASE("com.puppycrawl.tools.checkstyle.checks.HexLiteralCaseCheck"),
     NUMERICAL_PREFIXES_INF_SUF_CASE(
       "com.puppycrawl.tools.checkstyle.checks.NumericalPrefixesInfixesSuffixesCharacterCaseCheck"),
+    UNUSED_IMPORT("com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck"),
     REDUNDANT_IMPORT("com.puppycrawl.tools.checkstyle.checks.imports.RedundantImportCheck");
 
     private final String id;

src/main/java/org/checkstyle/autofix/CheckstyleRecipeRegistry.java

@@ -33,6 +33,7 @@
 import org.checkstyle.autofix.recipe.NewlineAtEndOfFile;
 import org.checkstyle.autofix.recipe.NumericalPrefixesInfixesSuffixesCharacterCase;
 import org.checkstyle.autofix.recipe.RedundantImport;
+import org.checkstyle.autofix.recipe.UnusedImports;
 import org.checkstyle.autofix.recipe.UpperEll;
 import org.openrewrite.Recipe;
 
@@ -54,6 +55,7 @@ public final class CheckstyleRecipeRegistry {
         RECIPE_MAP.put(CheckFullName.NUMERICAL_PREFIXES_INF_SUF_CASE,
             NumericalPrefixesInfixesSuffixesCharacterCase::new);
         RECIPE_MAP.put(CheckFullName.REDUNDANT_IMPORT, RedundantImport::new);
+        RECIPE_MAP.put(CheckFullName.UNUSED_IMPORT, UnusedImports::new);
     }
 
     private CheckstyleRecipeRegistry() {

src/main/java/org/checkstyle/autofix/recipe/UnusedImports.java

@@ -0,0 +1,92 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// checkstyle-openrewrite-recipes: Automatically fix Checkstyle violations with OpenRewrite.
+// Copyright (C) 2025 The Checkstyle OpenRewrite Recipes Authors
+//
+// 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
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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.checkstyle.autofix.recipe;
+
+import java.nio.file.Path;
+import java.util.List;
+
+import org.checkstyle.autofix.parser.CheckstyleViolation;
+import org.openrewrite.ExecutionContext;
+import org.openrewrite.Recipe;
+import org.openrewrite.TreeVisitor;
+import org.openrewrite.java.JavaIsoVisitor;
+import org.openrewrite.java.tree.J;
+
+/**
+ * Fixes Checkstyle UnusedImports violations by removing unused imports.
+ */
+public class UnusedImports extends Recipe {
+
+    private final List<CheckstyleViolation> violations;
+
+    public UnusedImports(List<CheckstyleViolation> violations) {
+        this.violations = violations;
+    }
+
+    @Override
+    public String getDisplayName() {
+        return "UnusedImports Recipe";
+    }
+
+    @Override
+    public String getDescription() {
+        return "Remove unused imports";
+    }
+
+    @Override
+    public TreeVisitor<?, ExecutionContext> getVisitor() {
+        return new UnusedImports.UnusedImportsVisitor();
+    }
+
+    private final class UnusedImportsVisitor extends JavaIsoVisitor<ExecutionContext> {
+
+        private static final String DOT_OPERATOR = ".";
+
+        private Path sourcePath;
+
+        @Override
+        public J.CompilationUnit visitCompilationUnit(J.CompilationUnit cu,
+                                                      ExecutionContext executionContext) {
+
+            this.sourcePath = cu.getSourcePath();
+            return cu.withImports(
+                    cu.getImports().stream()
+                            .filter(importStmt -> !isAtViolationLocation(importStmt))
+                            .toList()
+            );
+        }
+
+        private String createMessage(J.Import literal) {
+            String fullImport = literal.getTypeName();
+            if (literal.isStatic()) {
+                fullImport += DOT_OPERATOR + literal.getQualid().getSimpleName();
+            }
+            return "Unused import - " + fullImport + DOT_OPERATOR;
+        }
+
+        private boolean isAtViolationLocation(J.Import literal) {
+
+            final String message = createMessage(literal);
+            return violations.stream().anyMatch(violation -> {
+                final Path absolutePath = violation.getFilePath();
+                return violation.getMessage().equals(message)
+                        && absolutePath.endsWith(sourcePath);
+            });
+        }
+    }
+}

src/test/java/org/checkstyle/autofix/recipe/UnusedImportsTest.java

@@ -0,0 +1,69 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// checkstyle-openrewrite-recipes: Automatically fix Checkstyle violations with OpenRewrite.
+// Copyright (C) 2025 The Checkstyle OpenRewrite Recipes Authors
+//
+// 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
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// 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.checkstyle.autofix.recipe;
+
+import static com.google.common.truth.Truth.assertWithMessage;
+
+import org.checkstyle.autofix.parser.ReportParser;
+import org.junit.jupiter.api.Test;
+
+public class UnusedImportsTest extends AbstractRecipeTestSupport {
+
+    @Override
+    protected String getSubpackage() {
+        return "unusedimports";
+    }
+
+    @Test
+    public void checkDescription() {
+        final UnusedImports recipe = new UnusedImports(null);
+        final String expectedDescription = "Remove unused imports";
+        assertWithMessage("Invalid description")
+                .that(recipe.getDescription())
+                .isEqualTo(expectedDescription);
+    }
+
+    @Test
+    public void checkDisplayName() {
+        final UnusedImports recipe = new UnusedImports(null);
+        final String expectedDisplayName = "UnusedImports Recipe";
+        assertWithMessage("Invalid display name")
+                .that(recipe.getDisplayName())
+                .isEqualTo(expectedDisplayName);
+    }
+
+    @RecipeTest
+    void unusedImportsCaseOne(ReportParser parser) throws Exception {
+        verify(parser, "UnusedCaseOne");
+    }
+
+    @RecipeTest
+    void unusedImportsCaseTwo(ReportParser parser) throws Exception {
+        verify(parser, "UnusedCaseTwo");
+    }
+
+    @RecipeTest
+    void unusedImportsCaseThree(ReportParser parser) throws Exception {
+        verify(parser, "UnusedCaseOne", "UnusedCaseTwo");
+    }
+
+    @RecipeTest
+    void unusedImportsCaseFour(ReportParser parser) throws Exception {
+        verify(parser, "UnusedCaseThree");
+    }
+}

src/test/resources/org/checkstyle/autofix/recipe/unusedimports/unusedcaseone/DiffUnusedCaseOne.diff

@@ -0,0 +1,40 @@
+--- src/test/resources/org/checkstyle/autofix/recipe/unusedimports/unusedcaseone/InputUnusedCaseOne.java
++++ src/test/resources/org/checkstyle/autofix/recipe/unusedimports/unusedcaseone/OutputUnusedCaseOne.java
+@@ -11,28 +11,17 @@
+
+ import java.io.*;
+ import java.lang.*;
+-import java.lang.String; // violation 'Unused import - java.lang.String.'
+-
+-import java.util.List; // violation 'Unused import - java.util.List.'
+-import java.util.List; // violation 'Unused import - java.util.List.'
+ import java.lang.*;
+ import java.util.Iterator;
+-import java.util.Enumeration; // violation 'Unused import - java.util.Enumeration.'
+ import java.util.Arrays;
+ import javax.swing.JToolBar;
+-import javax.swing.JToggleButton; // violation 'Unused import - javax.swing.JToggleButton.'
+-
+-import javax.swing.BorderFactory; // violation 'Unused import - javax.swing.BorderFactory.'
+
+ import static java.io.File.listRoots;
+
+ import static javax.swing.WindowConstants.*;
+-import static java.io.File. // violation 'Unused import - java.io.File.createTempFile.'
+-    createTempFile;
+
+ import java.awt.Graphics2D;
+ import java.awt.HeadlessException;
+-import java.awt.Label; // violation 'Unused import - java.awt.Label.'
+ import java.util.Date;
+ import java.util.Calendar;
+ import java.util.BitSet;
+@@ -42,7 +31,7 @@
+  * Here's an import used only by javadoc: {@link Date}.
+  * @see Calendar Should avoid unused import for Calendar
+  **/
+-public class InputUnusedCaseOne {
++public class OutputUnusedCaseOne {
+
+     private Class mUse1 = null;
+     private Class mUse2 = java.io.File.class;

src/test/resources/org/checkstyle/autofix/recipe/unusedimports/unusedcaseone/InputUnusedCaseOne.java

@@ -0,0 +1,79 @@
+/*xml
+<module name="Checker">
+  <module name="TreeWalker">
+    <module name="com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck"/>
+  </module>
+</module>
+
+*/
+
+package org.checkstyle.autofix.recipe.unusedimports.unusedcaseone;
+
+import java.io.*;
+import java.lang.*;
+import java.lang.String; // violation 'Unused import - java.lang.String.'
+
+import java.util.List; // violation 'Unused import - java.util.List.'
+import java.util.List; // violation 'Unused import - java.util.List.'
+import java.lang.*;
+import java.util.Iterator;
+import java.util.Enumeration; // violation 'Unused import - java.util.Enumeration.'
+import java.util.Arrays;
+import javax.swing.JToolBar;
+import javax.swing.JToggleButton; // violation 'Unused import - javax.swing.JToggleButton.'
+
+import javax.swing.BorderFactory; // violation 'Unused import - javax.swing.BorderFactory.'
+
+import static java.io.File.listRoots;
+
+import static javax.swing.WindowConstants.*;
+import static java.io.File. // violation 'Unused import - java.io.File.createTempFile.'
+    createTempFile;
+
+import java.awt.Graphics2D;
+import java.awt.HeadlessException;
+import java.awt.Label; // violation 'Unused import - java.awt.Label.'
+import java.util.Date;
+import java.util.Calendar;
+import java.util.BitSet;
+
+/**
+ * Test case for imports
+ * Here's an import used only by javadoc: {@link Date}.
+ * @see Calendar Should avoid unused import for Calendar
+ **/
+public class InputUnusedCaseOne {
+
+    private Class mUse1 = null;
+    private Class mUse2 = java.io.File.class;
+    private Class mUse3 = Iterator[].class;
+    private Class mUse4 = java.util.Enumeration[].class;
+
+    {
+        int[] x = {};
+        Arrays.sort(x);
+        Object obj = javax.swing.BorderFactory.createEmptyBorder();
+        File[] files = listRoots();
+    }
+
+    private JToolBar.Separator mSep = null;
+
+    private Object mUse5 = new Object();
+
+    private Object mUse6 = new javax.swing.JToggleButton.ToggleButtonModel();
+
+    private int Component;
+
+    /**
+     * method comment with JavaDoc-only import {@link BitSet}
+     */
+    public void Label() {}
+
+    /**
+     * Renders to a {@linkplain Graphics2D graphics context}.
+     * @throws HeadlessException if no graphis environment can be found.
+     */
+    public void render() {}
+
+    public void aMethodWithManyLinks() {}
+}

src/test/resources/org/checkstyle/autofix/recipe/unusedimports/unusedcaseone/OutputUnusedCaseOne.java

@@ -0,0 +1,68 @@
+/*xml
+<module name="Checker">
+  <module name="TreeWalker">
+    <module name="com.puppycrawl.tools.checkstyle.checks.imports.UnusedImportsCheck"/>
+  </module>
+</module>
+
+*/
+
+package org.checkstyle.autofix.recipe.unusedimports.unusedcaseone;
+
+import java.io.*;
+import java.lang.*;
+import java.lang.*;
+import java.util.Iterator;
+import java.util.Arrays;
+import javax.swing.JToolBar;
+
+import static java.io.File.listRoots;
+
+import static javax.swing.WindowConstants.*;
+
+import java.awt.Graphics2D;
+import java.awt.HeadlessException;
+import java.util.Date;
+import java.util.Calendar;
+import java.util.BitSet;
+
+/**
+ * Test case for imports
+ * Here's an import used only by javadoc: {@link Date}.
+ * @see Calendar Should avoid unused import for Calendar
+ **/
+public class OutputUnusedCaseOne {
+
+    private Class mUse1 = null;
+    private Class mUse2 = java.io.File.class;
+    private Class mUse3 = Iterator[].class;
+    private Class mUse4 = java.util.Enumeration[].class;
+
+    {
+        int[] x = {};
+        Arrays.sort(x);
+        Object obj = javax.swing.BorderFactory.createEmptyBorder();
+        File[] files = listRoots();
+    }
+
+    private JToolBar.Separator mSep = null;
+
+    private Object mUse5 = new Object();
+
+    private Object mUse6 = new javax.swing.JToggleButton.ToggleButtonModel();
+
+    private int Component;
+
+    /**
+     * method comment with JavaDoc-only import {@link BitSet}
+     */
+    public void Label() {}
+
+    /**
+     * Renders to a {@linkplain Graphics2D graphics context}.
+     * @throws HeadlessException if no graphis environment can be found.
+     */
+    public void render() {}
+
+    public void aMethodWithManyLinks() {}
+}