Add YAML utils (#709)

Signed-off-by: Valentin Delaye <jonesbusy@users.noreply.github.com>

Author: jonesbusy

pom.xml

@@ -250,6 +250,10 @@
       <groupId>tools.jackson.dataformat</groupId>
       <artifactId>jackson-dataformat-toml</artifactId>
     </dependency>
+    <dependency>
+      <groupId>tools.jackson.dataformat</groupId>
+      <artifactId>jackson-dataformat-yaml</artifactId>
+    </dependency>
 
     <!-- Test dependencies -->
     <dependency>

src/main/java/land/oras/utils/YamlUtils.java

@@ -0,0 +1,99 @@
+/*-
+ * =LICENSE=
+ * ORAS Java SDK
+ * ===
+ * Copyright (C) 2024 - 2025 ORAS
+ * ===
+ * 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.
+ * =LICENSEEND=
+ */
+
+package land.oras.utils;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import land.oras.exception.OrasException;
+import org.jspecify.annotations.NullMarked;
+import tools.jackson.core.JacksonException;
+import tools.jackson.databind.ObjectMapper;
+import tools.jackson.dataformat.yaml.YAMLMapper;
+
+/**
+ * Utility class for YAML operations.
+ * Use Jackson 3 internally for YAML operations
+ */
+@NullMarked
+public final class YamlUtils {
+
+    /**
+     * TOML mapper instance
+     */
+    private static final ObjectMapper yamlMapper;
+
+    /**
+     * Utils class
+     */
+    private YamlUtils() {
+        // Hide constructor
+    }
+
+    static {
+        yamlMapper = YAMLMapper.builder().build();
+    }
+
+    /**
+     * Convert an object to a YAML string
+     * @param object The object to convert
+     * @return The YAML string
+     */
+    public static String toYaml(Object object) {
+        try {
+            return yamlMapper.writeValueAsString(object);
+        } catch (JacksonException e) {
+            throw new OrasException("Unable to convert object to YAML string", e);
+        }
+    }
+
+    /**
+     * Convert a YAML string to an object
+     * @param yaml The YAML string
+     * @param clazz The class of the object
+     * @param <T> The type of the object
+     * @return The object
+     */
+    public static <T> T fromYaml(String yaml, Class<T> clazz) {
+        try {
+            return yamlMapper.readValue(yaml, clazz);
+        } catch (JacksonException e) {
+            throw new OrasException("Unable to parse YAML string", e);
+        }
+    }
+
+    /**
+     * Read a YAML file and convert its contents to an object.
+     * The file at the given {@code path} is read as UTF-8 YAML and deserialized into the specified type.
+     * @param path The path to the YAML file
+     * @param clazz The class of the object
+     * @param <T> The type of the object
+     * @return The object deserialized from the YAML file
+     */
+    public static <T> T fromYaml(Path path, Class<T> clazz) {
+        try {
+            return yamlMapper.readValue(Files.readString(path, StandardCharsets.UTF_8), clazz);
+        } catch (IOException | JacksonException e) {
+            throw new OrasException("Unable to read YAML from file", e);
+        }
+    }
+}

src/test/java/land/oras/utils/YamlUtilsTest.java

@@ -0,0 +1,107 @@
+/*-
+ * =LICENSE=
+ * ORAS Java SDK
+ * ===
+ * Copyright (C) 2024 - 2025 ORAS
+ * ===
+ * 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.
+ * =LICENSEEND=
+ */
+
+package land.oras.utils;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.util.LinkedHashMap;
+import java.util.Map;
+import land.oras.exception.OrasException;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.CleanupMode;
+import org.junit.jupiter.api.io.TempDir;
+import org.junit.jupiter.api.parallel.Execution;
+import org.junit.jupiter.api.parallel.ExecutionMode;
+
+@Execution(ExecutionMode.CONCURRENT)
+class YamlUtilsTest {
+
+    /**
+     * Temporary dir
+     */
+    @TempDir(cleanup = CleanupMode.ON_SUCCESS)
+    private static Path dir;
+
+    @Test
+    void failToParseYamlString() {
+        assertThrows(OrasException.class, () -> YamlUtils.fromYaml("not a yaml: too, bar: test", Object.class));
+    }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    void shouldParseYaml() {
+        String yamlMap =
+                """
+                ---
+                key1: "value1"
+                key2: "value2"
+                """;
+        Map<String, String> map = YamlUtils.fromYaml(yamlMap, Map.class);
+        assertNotNull(map);
+        assertEquals(2, map.size());
+        assertEquals("value1", map.get("key1"));
+        assertEquals("value2", map.get("key2"));
+    }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    void shouldParseYamlFile() throws IOException {
+        String yamlMap =
+                """
+                ---
+                key1: "value1"
+                key2: "value2"
+                """;
+        Path yamlFile = dir.resolve("test.yaml");
+        Files.writeString(yamlFile, yamlMap);
+        Map<String, String> map = YamlUtils.fromYaml(yamlFile, Map.class);
+        assertNotNull(map);
+        assertEquals(2, map.size());
+        assertEquals("value1", map.get("key1"));
+        assertEquals("value2", map.get("key2"));
+    }
+
+    @Test
+    @SuppressWarnings("unchecked")
+    void shouldFailToParseYamlFile() {
+        assertThrows(OrasException.class, () -> YamlUtils.fromYaml(Path.of("foo.yaml"), Map.class));
+    }
+
+    @Test
+    void shouldConvertToYaml() {
+        Map<String, String> map = new LinkedHashMap<>();
+        map.put("key1", "value1");
+        map.put("key2", "value2");
+        String yaml = YamlUtils.toYaml(map);
+        assertNotNull(yaml);
+        String expected = """
+            ---
+            key1: "value1"
+            key2: "value2"
+            """;
+        assertEquals(expected, yaml);
+    }
+}