Add support for SLF4J discovery via service loader (fixes tinylog-org…

…#119)

pom.xml

@@ -87,7 +87,7 @@
 		<mockk.version>1.11.0</mockk.version>
 		<powermock.version>2.0.9</powermock.version>
 		<scala.version>2.12.13</scala.version>
-		<slf4j.version>1.7.30</slf4j.version>
+		<slf4j.version>1.8.0-beta4</slf4j.version>
 
 	</properties>
 

slf4j-tinylog/src/main/java/org/tinylog/slf4j/TinylogSlf4jServiceProvider.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright 2018 Martin Winandy
+ *
+ * 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.tinylog.slf4j;
+
+import org.slf4j.ILoggerFactory;
+import org.slf4j.IMarkerFactory;
+import org.slf4j.helpers.BasicMarkerFactory;
+import org.slf4j.spi.MDCAdapter;
+import org.slf4j.spi.SLF4JServiceProvider;
+
+/**
+ * SPI implementation for SLF4j 1.8+. Replacement mechanism for {@link org.slf4j.impl.StaticLoggerBinder}.
+ */
+public class TinylogSlf4jServiceProvider implements SLF4JServiceProvider {
+
+	/**
+	 * SLF4J API 1.8 and newer is supported.
+	 */
+	public static final String REQUESTED_API_VERSION = "1.8";
+
+	private ILoggerFactory loggerFactory;
+	private IMarkerFactory markerFactory;
+	private MDCAdapter mdcAdapter;
+
+	/** */
+	public TinylogSlf4jServiceProvider() {
+	}
+
+	@Override
+	public ILoggerFactory getLoggerFactory() {
+		return loggerFactory;
+	}
+
+	@Override
+	public IMarkerFactory getMarkerFactory() {
+		return markerFactory;
+	}
+
+	@Override
+	public MDCAdapter getMDCAdapter() {
+		return mdcAdapter;
+	}
+
+	@Override
+	public String getRequesteApiVersion() {
+		return REQUESTED_API_VERSION;
+	}
+
+	@Override
+	public void initialize() {
+		loggerFactory = new TinylogLoggerFactory();
+		markerFactory = new BasicMarkerFactory();
+		mdcAdapter = new TinylogMdcAdapter();
+	}
+}

slf4j-tinylog/src/main/resources/META-INF/services/org.slf4j.spi.SLF4JServiceProvider

@@ -0,0 +1 @@
+org.tinylog.slf4j.TinylogSlf4jServiceProvider