Split off YAML configuration into its own module

This splits `YamlConfiguration` into its own module and removes
`jackson-dataformat-yaml` from `log4j-core`'s optional dependencies.

Author: ppkarwasz

log4j-config-yaml/pom.xml

@@ -0,0 +1,66 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Licensed to the Apache Software Foundation (ASF) under one or more
+  ~ contributor license agreements.  See the NOTICE file distributed with
+  ~ this work for additional information regarding copyright ownership.
+  ~ The ASF licenses this file to you 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.
+  -->
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <parent>
+    <groupId>org.apache.logging.log4j</groupId>
+    <artifactId>log4j</artifactId>
+    <version>${revision}</version>
+    <relativePath>../log4j-parent</relativePath>
+  </parent>
+
+  <artifactId>log4j-config-yaml</artifactId>
+
+  <dependencies>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-core</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>com.fasterxml.jackson.dataformat</groupId>
+      <artifactId>jackson-dataformat-yaml</artifactId>
+    </dependency>
+
+    <dependency>
+      <groupId>org.apache.logging.log4j</groupId>
+      <artifactId>log4j-core-test</artifactId>
+      <scope>test</scope>
+    </dependency>
+
+  </dependencies>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <annotationProcessorPaths combine.children="append">
+            <path>
+              <groupId>org.apache.logging.log4j</groupId>
+              <artifactId>log4j-plugin-processor</artifactId>
+              <version>${project.version}</version>
+            </path>
+          </annotationProcessorPaths>
+        </configuration>
+      </plugin>
+    </plugins>
+  </build>
+</project>

log4j-core/src/main/java/org/apache/logging/log4j/core/config/yaml/YamlConfiguration.java renamed to log4j-config-yaml/src/main/java/org/apache/logging/log4j/core/config/yaml/YamlConfiguration.java

@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package org.apache.logging.log4j.core.config;
+package org.apache.logging.log4j.config.yaml;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertNotNull;
@@ -24,6 +24,7 @@
 import org.apache.logging.log4j.core.appender.rolling.SizeBasedTriggeringPolicy;
 import org.apache.logging.log4j.core.appender.rolling.TimeBasedTriggeringPolicy;
 import org.apache.logging.log4j.core.appender.rolling.TriggeringPolicy;
+import org.apache.logging.log4j.core.config.Configuration;
 import org.apache.logging.log4j.core.test.junit.LoggerContextSource;
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Tag;

log4j-core/src/main/java/org/apache/logging/log4j/core/config/yaml/YamlConfigurationFactory.java renamed to log4j-config-yaml/src/main/java/org/apache/logging/log4j/core/config/yaml/YamlConfigurationFactory.java

@@ -0,0 +1,39 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to you 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.apache.logging.log4j.config.yaml;
+
+import java.io.IOException;
+import java.nio.file.Path;
+import org.apache.logging.log4j.core.LoggerContext;
+import org.apache.logging.log4j.core.config.AbstractConfigurationFactoryTest;
+import org.apache.logging.log4j.core.test.junit.LoggerContextSource;
+import org.apache.logging.log4j.test.junit.TempLoggingDir;
+import org.junit.jupiter.api.Test;
+
+class YamlConfigurationFactoryTest extends AbstractConfigurationFactoryTest {
+
+    @TempLoggingDir
+    private static Path loggingPath;
+
+    @Test
+    @LoggerContextSource("YamlConfigurationFactoryTest.yaml")
+    void yamlConfiguration(final LoggerContext context) throws IOException {
+        checkConfiguration(context);
+        final Path logFile = loggingPath.resolve("test-yaml.log");
+        checkFileLogger(context, logFile);
+    }
+}