YAML implementation with Jackson

.gitignore

@@ -121,3 +121,6 @@ nbdist/
 nbactions.xml
 nb-configuration.xml
 .nb-gradle/
+
+# MacOS jenv
+.java-version

CHANGES.md

@@ -14,6 +14,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 * Add option `editorConfigFile` for `ktLint` [#142](https://github.com/diffplug/spotless/issues/142)
   * **POTENTIALLY BREAKING** `ktlint` step now modifies license headers. Make sure to put `licenseHeader` *after* `ktlint`.
 * Added `skipLinesMatching` option to `licenseHeader` to support formats where license header cannot be immediately added to the top of the file (e.g. xml, sh). ([#1441](https://github.com/diffplug/spotless/pull/1441)).
+* Add YAML support through Jackson ([#1478](https://github.com/diffplug/spotless/pull/1478))
 ### Fixed
 * Support `ktlint` 0.48+ new rule disabling syntax ([#1456](https://github.com/diffplug/spotless/pull/1456)) fixes ([#1444](https://github.com/diffplug/spotless/issues/1444))
 * Added support for npm-based [ESLint](https://eslint.org/)-formatter for javascript and typescript ([#1453](https://github.com/diffplug/spotless/pull/1453))

lib/build.gradle

@@ -14,7 +14,8 @@ def NEEDS_GLUE = [
 	'ktlint',
 	'flexmark',
 	'diktat',
-	'scalafmt'
+	'scalafmt',
+	'jackson'
 ]
 for (glue in NEEDS_GLUE) {
 	sourceSets.register(glue) {
@@ -55,6 +56,9 @@ dependencies {
 
 	palantirJavaFormatCompileOnly 'com.palantir.javaformat:palantir-java-format:1.1.0' 	// this version needs to stay compilable against Java 8 for CI Job testNpm
 
+	// used jackson-based formatters
+	jacksonCompileOnly 'com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.13.4'
+
 	String VER_KTFMT = '0.42'
 	ktfmtCompileOnly "com.facebook:ktfmt:$VER_KTFMT"
 	String VER_KTLINT_GOOGLE_JAVA_FORMAT = '1.7' // for JDK 8 compatibility

lib/src/jackson/java/com/diffplug/spotless/glue/yaml/YamlJacksonFormatterFunc.java

@@ -0,0 +1,99 @@
+/*
+ * Copyright 2021-2023 DiffPlug
+ *
+ * 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 com.diffplug.spotless.glue.yaml;
+
+import java.io.IOException;
+import java.util.List;
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.core.type.TypeReference;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.SerializationFeature;
+import com.fasterxml.jackson.databind.node.ObjectNode;
+import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+
+import com.diffplug.spotless.FormatterFunc;
+
+public class YamlJacksonFormatterFunc implements FormatterFunc {
+	private List<String> enabledFeatures;
+	private List<String> disabledFeatures;
+
+	// private static final Logger logger = LoggerFactory.getLogger(YamlJacksonFormatterFunc.class);
+
+	public YamlJacksonFormatterFunc(List<String> enabledFeatures, List<String> disabledFeatures) {
+		this.enabledFeatures = enabledFeatures;
+		this.disabledFeatures = disabledFeatures;
+	}
+
+	@Override
+	public String apply(String input) throws Exception {
+		ObjectMapper objectMapper = makeObjectMapper();
+
+		return format(objectMapper, input);
+	}
+
+	protected ObjectMapper makeObjectMapper() {
+		YAMLFactory yamlFactory = new YAMLFactory();
+		ObjectMapper objectMapper = new ObjectMapper(yamlFactory);
+
+		// Configure the ObjectMapper
+		// https://github.com/FasterXML/jackson-databind#commonly-used-features
+		for (String rawFeature : enabledFeatures) {
+			// https://stackoverflow.com/questions/3735927/java-instantiating-an-enum-using-reflection
+			SerializationFeature feature = SerializationFeature.valueOf(rawFeature);
+
+			objectMapper.enable(feature);
+		}
+
+		for (String rawFeature : disabledFeatures) {
+			// https://stackoverflow.com/questions/3735927/java-instantiating-an-enum-using-reflection
+			SerializationFeature feature = SerializationFeature.valueOf(rawFeature);
+
+			objectMapper.disable(feature);
+		}
+		return objectMapper;
+	}
+
+	protected String format(ObjectMapper objectMapper, String input) throws IllegalArgumentException, IOException {
+		// We may consider adding manually an initial '---' prefix to help management of multiple documents
+		// if (!input.trim().startsWith("---")) {
+		// 	input = "---" + "\n" + input;
+		// }
+
+		try {
+			// https://stackoverflow.com/questions/25222327/deserialize-pojos-from-multiple-yaml-documents-in-a-single-file-in-jackson
+			// https://github.com/FasterXML/jackson-dataformats-text/issues/66#issuecomment-375328648
+			// 2023-01: For now, we get 'Cannot deserialize value of type `com.fasterxml.jackson.databind.node.ObjectNode` from Array value'
+			//			JsonParser yamlParser = objectMapper.getFactory().createParser(input);
+			//			List<ObjectNode> docs = objectMapper.readValues(yamlParser, ObjectNode.class).readAll();
+			//			return objectMapper.writeValueAsString(docs);
+
+			// 2023-01: This returns JSON instead of YAML
+			// This will transit with a JsonNode
+			// A JsonNode may keep the comments from the input node
+			// JsonNode jsonNode = objectMapper.readTree(input);
+			//Not 'toPrettyString' as one could require no INDENT_OUTPUT
+			// return jsonNode.toPrettyString();
+			ObjectNode objectNode = objectMapper.readValue(input, ObjectNode.class);
+			return objectMapper.writeValueAsString(objectNode);
+		} catch (JsonProcessingException e) {
+			throw new AssertionError("Unable to format YAML. input='" + input + "'", e);
+		}
+	}
+
+	// Spotbugs
+	private static class ObjectNodeTypeReference extends TypeReference<ObjectNode> {}
+}

lib/src/main/java/com/diffplug/spotless/yaml/YamlJacksonStep.java

@@ -0,0 +1,157 @@
+/*
+ * Copyright 2021-2023 DiffPlug
+ *
+ * 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 com.diffplug.spotless.yaml;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+import com.diffplug.spotless.FormatterFunc;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.JarState;
+import com.diffplug.spotless.Provisioner;
+
+/**
+ * Simple YAML formatter which reformats the file according to Jackson YAMLFactory.
+ */
+// https://stackoverflow.com/questions/14515994/convert-json-string-to-pretty-print-json-output-using-jackson
+public final class YamlJacksonStep {
+	static final String MAVEN_COORDINATE = "com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:";
+	static final String DEFAULT_VERSION = "2.13.4";
+
+	public static String defaultVersion() {
+		return DEFAULT_VERSION;
+	}
+
+	public static FormatterStep create(List<String> enabledFeatures,
+			List<String> disabledFeatures,
+			String jacksonVersion,
+			Provisioner provisioner) {
+		Objects.requireNonNull(provisioner, "provisioner cannot be null");
+		return FormatterStep.createLazy("yaml",
+				() -> new State(enabledFeatures, disabledFeatures, jacksonVersion, provisioner),
+				State::toFormatter);
+	}
+
+	public static FormatterStep create(Provisioner provisioner) {
+		return create(Arrays.asList("INDENT_OUTPUT"), Arrays.asList(), defaultVersion(), provisioner);
+	}
+
+	private static final class State implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		private final List<String> enabledFeatures;
+		private final List<String> disabledFeatures;
+
+		private final JarState jarState;
+
+		private State(List<String> enabledFeatures,
+				List<String> disabledFeatures,
+				String jacksonVersion,
+				Provisioner provisioner) throws IOException {
+			this.enabledFeatures = enabledFeatures;
+			this.disabledFeatures = disabledFeatures;
+
+			this.jarState = JarState.from(MAVEN_COORDINATE + jacksonVersion, provisioner);
+		}
+
+		FormatterFunc toFormatter() {
+			Class<?> jsonFactoryClass;
+			Class<?> yamlFactoryClass;
+			Class<?> objectMapperClass;
+
+			Class<?> serializationFeatureClass;
+			Method enableFeature;
+			Method disableFeature;
+
+			Method stringToNode;
+			Method nodeToString;
+			try {
+				ClassLoader classLoader = jarState.getClassLoader();
+				jsonFactoryClass = classLoader.loadClass("com.fasterxml.jackson.core.JsonFactory");
+				yamlFactoryClass = classLoader.loadClass("com.fasterxml.jackson.dataformat.yaml.YAMLFactory");
+
+				objectMapperClass = classLoader.loadClass("com.fasterxml.jackson.databind.ObjectMapper");
+
+				// Configure the ObjectMapper
+				// https://github.com/FasterXML/jackson-databind#commonly-used-features
+				{
+					serializationFeatureClass = classLoader.loadClass("com.fasterxml.jackson.databind.SerializationFeature");
+					enableFeature = objectMapperClass.getMethod("enable", serializationFeatureClass);
+					disableFeature = objectMapperClass.getMethod("disable", serializationFeatureClass);
+				}
+
+				// https://stackoverflow.com/questions/25222327/deserialize-pojos-from-multiple-yaml-documents-in-a-single-file-in-jackson
+				// List<ObjectNode> docs = mapper
+				// .readValues<ObjectNode>(yamlParser, new TypeReference<ObjectNode> {})
+				// .readAll();
+
+				Class<?> jsonNodeClass = classLoader.loadClass("com.fasterxml.jackson.databind.JsonNode");
+
+				// This will transit with a JsonNode
+				// A JsonNode may keep the comments from the input node
+				stringToNode = objectMapperClass.getMethod("readTree", String.class);
+				// Not 'toPrettyString' as one could require no INDENT_OUTPUT
+				nodeToString = jsonNodeClass.getMethod("toPrettyString");
+			} catch (ClassNotFoundException | NoSuchMethodException e) {
+				throw new IllegalStateException("There was a problem preparing org.json dependencies", e);
+			}
+
+			return s -> {
+				if (s.isEmpty()) {
+					return s;
+				}
+
+				Object yamlFactory = yamlFactoryClass.getConstructor().newInstance();
+				Object objectMapper = objectMapperClass.getConstructor(jsonFactoryClass).newInstance(yamlFactory);
+
+				for (String feature : enabledFeatures) {
+					// https://stackoverflow.com/questions/3735927/java-instantiating-an-enum-using-reflection
+					Object indentOutput = Enum.valueOf(serializationFeatureClass.asSubclass(Enum.class), feature);
+
+					enableFeature.invoke(objectMapper, indentOutput);
+				}
+
+				for (String feature : disabledFeatures) {
+					// https://stackoverflow.com/questions/3735927/java-instantiating-an-enum-using-reflection
+					Object indentOutput = Enum.valueOf(serializationFeatureClass.asSubclass(Enum.class), feature);
+
+					disableFeature.invoke(objectMapper, indentOutput);
+				}
+
+				return format(objectMapper, stringToNode, nodeToString, s);
+			};
+		}
+
+		private String format(Object objectMapper, Method stringToNode, Method nodeToString, String s)
+				throws IllegalAccessException, IllegalArgumentException {
+			try {
+				Object node = stringToNode.invoke(objectMapper, s);
+				return (String) nodeToString.invoke(node);
+			} catch (InvocationTargetException ex) {
+				throw new AssertionError("Unable to format YAML", ex.getCause());
+			}
+		}
+	}
+
+	private YamlJacksonStep() {
+		// cannot be directly instantiated
+	}
+}

lib/src/main/java/com/diffplug/spotless/yaml/YamlJacksonV2Step.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2021-2023 DiffPlug
+ *
+ * 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 com.diffplug.spotless.yaml;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.lang.reflect.Constructor;
+import java.lang.reflect.InvocationTargetException;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Objects;
+
+import com.diffplug.spotless.FormatterFunc;
+import com.diffplug.spotless.FormatterStep;
+import com.diffplug.spotless.JarState;
+import com.diffplug.spotless.Provisioner;
+
+public class YamlJacksonV2Step {
+	private YamlJacksonV2Step() {}
+
+	public static String defaultVersion() {
+		return YamlJacksonStep.DEFAULT_VERSION;
+	}
+
+	public static FormatterStep create(List<String> enabledFeatures,
+			List<String> disabledFeatures,
+			String jacksonVersion,
+			Provisioner provisioner) {
+		Objects.requireNonNull(provisioner, "provisioner cannot be null");
+		return FormatterStep.createLazy("yaml",
+				() -> new State(enabledFeatures, disabledFeatures, jacksonVersion, provisioner),
+				State::toFormatter);
+	}
+
+	public static FormatterStep create(Provisioner provisioner) {
+		return create(Arrays.asList("INDENT_OUTPUT"), Arrays.asList(), defaultVersion(), provisioner);
+	}
+
+	private static final class State implements Serializable {
+		private static final long serialVersionUID = 1L;
+
+		private final List<String> enabledFeatures;
+		private final List<String> disabledFeatures;
+
+		private final JarState jarState;
+
+		private State(List<String> enabledFeatures,
+				List<String> disabledFeatures,
+				String jacksonVersion,
+				Provisioner provisioner) throws IOException {
+			this.enabledFeatures = enabledFeatures;
+			this.disabledFeatures = disabledFeatures;
+
+			this.jarState = JarState.from(YamlJacksonStep.MAVEN_COORDINATE + jacksonVersion, provisioner);
+		}
+
+		FormatterFunc toFormatter() throws ClassNotFoundException, NoSuchMethodException, InvocationTargetException,
+				InstantiationException, IllegalAccessException {
+			Class<?> formatterFunc = jarState.getClassLoader().loadClass("com.diffplug.spotless.glue.yaml.YamlJacksonFormatterFunc");
+			Constructor<?> constructor = formatterFunc.getConstructor(List.class, List.class);
+			return (FormatterFunc) constructor.newInstance(enabledFeatures, disabledFeatures);
+		}
+	}
+}

plugin-maven/CHANGES.md

@@ -5,9 +5,10 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Added
 * Add option `editorConfigFile` for `ktLint` [#142](https://github.com/diffplug/spotless/issues/142)
-  * **POTENTIALLY BREAKING** `ktlint` step now modifies license headers. Make sure to put `licenseHeader` *after* `ktlint`.
+* **POTENTIALLY BREAKING** `ktlint` step now modifies license headers. Make sure to put `licenseHeader` *after* `ktlint`.
 * Added `skipLinesMatching` option to `licenseHeader` to support formats where license header cannot be immediately added to the top of the file (e.g. xml, sh). ([#1441](https://github.com/diffplug/spotless/pull/1441))
 * Add JSON support ([#1446](https://github.com/diffplug/spotless/pull/1446))
+* Add YAML support through Jackson ([#1478](https://github.com/diffplug/spotless/pull/1478))
 ### Fixed
 * Support `ktlint` 0.48+ new rule disabling syntax ([#1456](https://github.com/diffplug/spotless/pull/1456)) fixes ([#1444](https://github.com/diffplug/spotless/issues/1444))
 * Added support for npm-based [ESLint](https://eslint.org/)-formatter for javascript and typescript ([#1453](https://github.com/diffplug/spotless/pull/1453))