Implemented Report and Config Parsner

config/import-control-test.xml

@@ -8,5 +8,7 @@
     <allow pkg="org.openrewrite"/>
     <allow pkg="org.checkstyle"/>
     <allow pkg="java.io"/>
+    <allow pkg="java.util"/>
     <allow pkg="java.nio"/>
+    <allow pkg="java.lang"/>
 </import-control>

config/import-control.xml

@@ -8,6 +8,7 @@
     <allow pkg="org.openrewrite.java"/>
     <allow pkg="org.openrewrite.java.tree"/>
     <allow pkg="java"/>
+    <allow pkg="javax.xml.stream"/>
     <allow pkg="org.checkstyle"/>
     <allow pkg="java.util"/>
-</import-control>
+</import-control>

config/suppressions.xml

@@ -4,4 +4,8 @@
         "-//Checkstyle//DTD SuppressionFilter Configuration 1.1//EN"
         "https://checkstyle.org/dtds/suppressions_1_1.dtd">
 
-<suppressions/>
+<suppressions>
+    <suppress checks="MissingJavadocType" files=".*"/>
+    <suppress checks="JavadocVariable" files=".*"/>
+    <suppress checks="MissingJavadocMethod" files=".*"/>
+</suppressions>

pom.xml

@@ -44,6 +44,14 @@
     </dependencyManagement>
 
     <dependencies>
+
+        <!-- Checkstyle dependency for parsing Checkstyle configs -->
+        <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>${checkstyle.version}</version>
+        </dependency>
+
         <!-- OpenRewrite core dependencies - using consistent versions -->
         <dependency>
             <groupId>org.openrewrite</groupId>

src/main/java/org/checkstyle/autofix/parser/CheckstyleReportsParser.java

@@ -0,0 +1,145 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// 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.parser;
+
+import java.io.FileInputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Objects;
+
+import javax.xml.stream.XMLEventReader;
+import javax.xml.stream.XMLInputFactory;
+import javax.xml.stream.XMLStreamException;
+import javax.xml.stream.events.Attribute;
+import javax.xml.stream.events.StartElement;
+import javax.xml.stream.events.XMLEvent;
+
+public final class CheckstyleReportsParser {
+
+    private static final String FILE_TAG = "file";
+
+    private static final String ERROR_TAG = "error";
+
+    private static final String FILENAME_ATTR = "name";
+
+    private static final String LINE_ATTR = "line";
+
+    private static final String COLUMN_ATTR = "column";
+
+    private static final String SEVERITY_ATTR = "severity";
+
+    private static final String MESSAGE_ATTR = "message";
+
+    private static final String SOURCE_ATTR = "source";
+
+    private CheckstyleReportsParser() {
+
+    }
+
+    public static List<CheckstyleViolation> parse(Path xmlPath)
+            throws IOException, XMLStreamException {
+
+        final List<CheckstyleViolation> result = new ArrayList<>();
+
+        try (InputStream inputStream = new FileInputStream(xmlPath.toFile())) {
+
+            final XMLInputFactory inputFactory = XMLInputFactory.newInstance();
+            final XMLEventReader reader = inputFactory.createXMLEventReader(inputStream);
+
+            try {
+                String filename = null;
+
+                while (reader.hasNext()) {
+                    final XMLEvent event = reader.nextEvent();
+                    if (event.isStartElement()) {
+                        final StartElement startElement = event.asStartElement();
+                        final String startElementName = startElement.getName().getLocalPart();
+
+                        if (FILE_TAG.equals(startElementName)) {
+                            filename = parseFileTag(startElement);
+                        }
+                        else if (ERROR_TAG.equals(startElementName)) {
+                            Objects.requireNonNull(filename, "File name can not be null");
+                            result.add(parseErrorTag(startElement, filename));
+                        }
+                    }
+                }
+            }
+            finally {
+                if (reader != null) {
+                    reader.close();
+                }
+            }
+        }
+
+        return result;
+    }
+
+    private static String parseFileTag(StartElement startElement) {
+        String fileName = null;
+        final Iterator<Attribute> attributes = startElement.getAttributes();
+        while (attributes.hasNext()) {
+            final Attribute attribute = attributes.next();
+            if (FILENAME_ATTR.equals(attribute.getName().getLocalPart())) {
+                fileName = attribute.getValue();
+                break;
+            }
+        }
+        return fileName;
+    }
+
+    private static CheckstyleViolation parseErrorTag(StartElement startElement, String filename) {
+        Integer line = null;
+        Integer column = null;
+        String source = null;
+        String message = null;
+        String severity = null;
+        final Iterator<Attribute> attributes = startElement
+                .getAttributes();
+        while (attributes.hasNext()) {
+            final Attribute attribute = attributes.next();
+            final String attrName = attribute.getName().getLocalPart();
+            switch (attrName) {
+                case LINE_ATTR:
+                    line = Integer.valueOf(attribute.getValue());
+                    break;
+                case COLUMN_ATTR:
+                    column = Integer.parseInt(attribute.getValue());
+                    break;
+                case SEVERITY_ATTR:
+                    severity = attribute.getValue();
+                    break;
+                case MESSAGE_ATTR:
+                    message = attribute.getValue();
+                    break;
+                case SOURCE_ATTR:
+                    source = attribute.getValue();
+                    break;
+                default:
+                    break;
+            }
+        }
+        return new CheckstyleViolation(
+                line, column, severity, source, message, filename);
+
+    }
+}

src/main/java/org/checkstyle/autofix/parser/CheckstyleViolation.java

@@ -0,0 +1,68 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// 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.parser;
+
+public final class CheckstyleViolation {
+
+    private final Integer line;
+
+    private final Integer column;
+
+    private final String severity;
+
+    private final String source;
+
+    private final String message;
+
+    private final String fileName;
+
+    public CheckstyleViolation(Integer line, Integer column,
+                               String severity, String source, String message, String fileName) {
+        this.line = line;
+        this.column = column;
+        this.severity = severity;
+        this.source = source;
+        this.message = message;
+        this.fileName = fileName;
+    }
+
+    public int getLine() {
+        return line;
+    }
+
+    public int getColumn() {
+        return column;
+    }
+
+    public String getSource() {
+        return source;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public String getFileName() {
+        return fileName;
+    }
+
+    public String getSeverity() {
+        return severity;
+    }
+
+}

src/main/java/org/checkstyle/autofix/parser/package-info.java

@@ -0,0 +1,21 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// 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.
+///////////////////////////////////////////////////////////////////////////////////////////////
+
+/**
+ * Provides classes to parse Checkstyle XML report files.
+ */
+package org.checkstyle.autofix.parser;

src/test/java/org/checkstyle/autofix/parser/CheckstyleReportsParserTest.java

@@ -0,0 +1,75 @@
+///////////////////////////////////////////////////////////////////////////////////////////////
+// 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.parser;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+
+import java.nio.file.Path;
+import java.util.List;
+import java.util.Map;
+import java.util.stream.Collectors;
+
+import org.junit.jupiter.api.Test;
+
+public class CheckstyleReportsParserTest {
+
+    private static String getPath(String path) {
+        return "src/test/resources/org/checkstyle/autofix/parser/" + path;
+    }
+
+    @Test
+    public void testParseFromResource() throws Exception {
+        final Path xmlPath = Path.of(getPath("checkstyle-report.xml"));
+        final List<CheckstyleViolation> records = CheckstyleReportsParser.parse(xmlPath);
+
+        assertNotNull(records);
+        assertEquals(1, records.size());
+
+        final CheckstyleViolation record = records.get(0);
+        assertEquals(42, record.getLine());
+        assertEquals(13, record.getColumn());
+        assertEquals("error", record.getSeverity());
+        assertEquals("Example message", record.getMessage());
+        assertEquals("com.puppycrawl.example.Check", record.getSource());
+        assertEquals("Example.java", record.getFileName());
+    }
+
+    @Test
+    public void testParseMultipleFilesReport() throws Exception {
+        final Path xmlPath = Path.of(getPath("checkstyle-multiple-files.xml"));
+        final List<CheckstyleViolation> records = CheckstyleReportsParser.parse(xmlPath);
+
+        assertNotNull(records);
+        assertEquals(3, records.size());
+
+        final Map<String, List<CheckstyleViolation>> grouped = records.stream()
+                .collect(Collectors.groupingBy(CheckstyleViolation::getFileName));
+
+        assertEquals(2, grouped.size());
+
+        assertEquals(2, grouped.get("Main.java").size());
+        assertEquals(1, grouped.get("Utils.java").size());
+
+        CheckstyleViolation record = grouped.get("Main.java").get(0);
+        assertEquals("error", record.getSeverity());
+
+        record = grouped.get("Utils.java").get(0);
+        assertEquals("warning", record.getSeverity());
+    }
+}

src/test/resources/org/checkstyle/autofix/parser/checkstyle-multiple-files.xml

@@ -0,0 +1,9 @@
+<checkstyle>
+    <file name="Main.java">
+        <error line="10" column="5" severity="error" message="Missing javadoc" source="com.puppycrawl.Check"/>
+        <error line="20" column="2" severity="error" message="Indentation" source="com.puppycrawl.Indent"/>
+    </file>
+    <file name="Utils.java">
+        <error line="15" column="1" severity="warning" message="Unused import" source="com.puppycrawl.Import"/>
+    </file>
+</checkstyle>

src/test/resources/org/checkstyle/autofix/parser/checkstyle-report.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<checkstyle version="8.0">
+    <file name="Example.java">
+        <error line="42" column="13" severity="error"
+               message="Example message"
+               source="com.puppycrawl.example.Check"/>
+    </file>
+</checkstyle>