Extract logging listeners

Separate logging ApplicationListeners classes to a different package
so that the root `logging` package is no longer aware of `context`
concerns.

Fixes gh-8611

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/BackgroundPreinitializer.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -21,7 +21,7 @@ import javax.validation.Validation;
 import org.apache.catalina.mbeans.MBeanFactory;
 
 import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEvent;
-import org.springframework.boot.logging.LoggingApplicationListener;
+import org.springframework.boot.context.logging.LoggingApplicationListener;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.annotation.Order;
 import org.springframework.format.support.DefaultFormattingConversionService;

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/RemoteSpringApplication.java

@@ -26,12 +26,12 @@ import org.springframework.boot.SpringApplication;
 import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.context.config.AnsiOutputApplicationListener;
 import org.springframework.boot.context.config.ConfigFileApplicationListener;
+import org.springframework.boot.context.logging.ClasspathLoggingApplicationListener;
+import org.springframework.boot.context.logging.LoggingApplicationListener;
 import org.springframework.boot.devtools.remote.client.RemoteClientConfiguration;
 import org.springframework.boot.devtools.restart.RestartInitializer;
 import org.springframework.boot.devtools.restart.RestartScopeInitializer;
 import org.springframework.boot.devtools.restart.Restarter;
-import org.springframework.boot.logging.ClasspathLoggingApplicationListener;
-import org.springframework.boot.logging.LoggingApplicationListener;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ApplicationListener;
 import org.springframework.core.io.ClassPathResource;

spring-boot-parent/src/checkstyle/import-control.xml

@@ -3,6 +3,12 @@
 <import-control pkg="org.springframework.boot">
 	<allow pkg=".*" regex="true" />
 
+	<!-- Logging -->
+	<subpackage name="logging">
+		<disallow pkg="org.springframework.context" />
+		<disallow pkg="org.springframework.boot.context" />
+	</subpackage>
+
 	<!-- Web related concerns -->
 	<subpackage name="web">
 

spring-boot/src/main/java/org/springframework/boot/logging/ClasspathLoggingApplicationListener.java → spring-boot/src/main/java/org/springframework/boot/context/logging/ClasspathLoggingApplicationListener.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.logging;
+package org.springframework.boot.context.logging;
 
 import java.net.URLClassLoader;
 import java.util.Arrays;
@@ -36,6 +36,7 @@ import org.springframework.core.ResolvableType;
  * context class loader (TCCL) at {@code DEBUG} level.
  *
  * @author Andy Wilkinson
+ * @since 2.0.0
  */
 public final class ClasspathLoggingApplicationListener
 		implements GenericApplicationListener {

spring-boot/src/main/java/org/springframework/boot/logging/LoggingApplicationListener.java → spring-boot/src/main/java/org/springframework/boot/context/logging/LoggingApplicationListener.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.logging;
+package org.springframework.boot.context.logging;
 
 import java.util.List;
 import java.util.Map;
@@ -31,6 +31,11 @@ import org.springframework.boot.context.event.ApplicationEnvironmentPreparedEven
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationPreparedEvent;
 import org.springframework.boot.context.event.ApplicationStartingEvent;
+import org.springframework.boot.logging.LogFile;
+import org.springframework.boot.logging.LogLevel;
+import org.springframework.boot.logging.LoggingInitializationContext;
+import org.springframework.boot.logging.LoggingSystem;
+import org.springframework.boot.logging.LoggingSystemProperties;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationEvent;
 import org.springframework.context.ApplicationListener;
@@ -72,6 +77,7 @@ import org.springframework.util.StringUtils;
  * @author Dave Syer
  * @author Phillip Webb
  * @author Andy Wilkinson
+ * @since 2.0.0
  * @see LoggingSystem#get(ClassLoader)
  */
 public class LoggingApplicationListener implements GenericApplicationListener {
@@ -94,57 +100,6 @@ public class LoggingApplicationListener implements GenericApplicationListener {
 	 */
 	public static final String REGISTER_SHUTDOWN_HOOK_PROPERTY = "logging.register-shutdown-hook";
 
-	/**
-	 * The name of the Spring property that contains the directory where log files are
-	 * written.
-	 * @deprecated as of 1.5 in favor of {@link LogFile#PATH_PROPERTY}
-	 */
-	@Deprecated
-	public static final String PATH_PROPERTY = LogFile.PATH_PROPERTY;
-
-	/**
-	 * The name of the Spring property that contains the name of the log file. Names can
-	 * be an exact location or relative to the current directory.
-	 * @deprecated as of 1.5 in favor of {@link LogFile#FILE_PROPERTY}
-	 */
-	@Deprecated
-	public static final String FILE_PROPERTY = LogFile.FILE_PROPERTY;
-
-	/**
-	 * The name of the System property that contains the process ID.
-	 */
-	public static final String PID_KEY = "PID";
-
-	/**
-	 * The name of the System property that contains the exception conversion word.
-	 */
-	public static final String EXCEPTION_CONVERSION_WORD = "LOG_EXCEPTION_CONVERSION_WORD";
-
-	/**
-	 * The name of the System property that contains the log file.
-	 */
-	public static final String LOG_FILE = "LOG_FILE";
-
-	/**
-	 * The name of the System property that contains the log path.
-	 */
-	public static final String LOG_PATH = "LOG_PATH";
-
-	/**
-	 * The name of the System property that contains the console log pattern.
-	 */
-	public static final String CONSOLE_LOG_PATTERN = "CONSOLE_LOG_PATTERN";
-
-	/**
-	 * The name of the System property that contains the file log pattern.
-	 */
-	public static final String FILE_LOG_PATTERN = "FILE_LOG_PATTERN";
-
-	/**
-	 * The name of the System property that contains the log level pattern.
-	 */
-	public static final String LOG_LEVEL_PATTERN = "LOG_LEVEL_PATTERN";
-
 	/**
 	 * The name of the {@link LoggingSystem} bean.
 	 */

spring-boot/src/main/java/org/springframework/boot/context/logging/package-info.java

+/*
+ * Copyright 2012-2017 the original author or 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.
+ */
+
+/**
+ * Logging integration with Spring's Application Context.
+ */
+package org.springframework.boot.context.logging;

spring-boot/src/main/java/org/springframework/boot/logging/LogFile.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -83,8 +83,8 @@ public class LogFile {
 	 * @param properties the properties to apply to
 	 */
 	public void applyTo(Properties properties) {
-		put(properties, LoggingApplicationListener.LOG_PATH, this.path);
-		put(properties, LoggingApplicationListener.LOG_FILE, toString());
+		put(properties, LoggingSystemProperties.LOG_PATH, this.path);
+		put(properties, LoggingSystemProperties.LOG_FILE, toString());
 	}
 
 	private void put(Properties properties, String key, String value) {

spring-boot/src/main/java/org/springframework/boot/logging/LoggingSystemProperties.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,28 +19,60 @@ package org.springframework.boot.logging;
 import org.springframework.boot.ApplicationPid;
 import org.springframework.boot.bind.RelaxedPropertyResolver;
 import org.springframework.core.env.Environment;
+import org.springframework.util.Assert;
 
 /**
  * Utility to set system properties that can later be used by log configuration files.
  *
  * @author Andy Wilkinson
  * @author Phillip Webb
+ * @since 2.0.0
  */
-class LoggingSystemProperties {
+public class LoggingSystemProperties {
 
-	static final String PID_KEY = LoggingApplicationListener.PID_KEY;
+	/**
+	 * The name of the System property that contains the process ID.
+	 */
+	public static final String PID_KEY = "PID";
 
-	static final String EXCEPTION_CONVERSION_WORD = LoggingApplicationListener.EXCEPTION_CONVERSION_WORD;
+	/**
+	 * The name of the System property that contains the exception conversion word.
+	 */
+	public static final String EXCEPTION_CONVERSION_WORD = "LOG_EXCEPTION_CONVERSION_WORD";
 
-	static final String CONSOLE_LOG_PATTERN = LoggingApplicationListener.CONSOLE_LOG_PATTERN;
+	/**
+	 * The name of the System property that contains the log file.
+	 */
+	public static final String LOG_FILE = "LOG_FILE";
 
-	static final String FILE_LOG_PATTERN = LoggingApplicationListener.FILE_LOG_PATTERN;
+	/**
+	 * The name of the System property that contains the log path.
+	 */
+	public static final String LOG_PATH = "LOG_PATH";
 
-	static final String LOG_LEVEL_PATTERN = LoggingApplicationListener.LOG_LEVEL_PATTERN;
+	/**
+	 * The name of the System property that contains the console log pattern.
+	 */
+	public static final String CONSOLE_LOG_PATTERN = "CONSOLE_LOG_PATTERN";
+
+	/**
+	 * The name of the System property that contains the file log pattern.
+	 */
+	public static final String FILE_LOG_PATTERN = "FILE_LOG_PATTERN";
+
+	/**
+	 * The name of the System property that contains the log level pattern.
+	 */
+	public static final String LOG_LEVEL_PATTERN = "LOG_LEVEL_PATTERN";
 
 	private final Environment environment;
 
-	LoggingSystemProperties(Environment environment) {
+	/**
+	 * Create a new {@link LoggingSystemProperties} instance.
+	 * @param environment the source environment
+	 */
+	public LoggingSystemProperties(Environment environment) {
+		Assert.notNull(environment, "Environment must not be null");
 		this.environment = environment;
 	}
 

spring-boot/src/main/resources/META-INF/spring.factories

@@ -22,9 +22,9 @@ org.springframework.boot.context.FileEncodingApplicationListener,\
 org.springframework.boot.context.config.AnsiOutputApplicationListener,\
 org.springframework.boot.context.config.ConfigFileApplicationListener,\
 org.springframework.boot.context.config.DelegatingApplicationListener,\
-org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener,\
-org.springframework.boot.logging.ClasspathLoggingApplicationListener,\
-org.springframework.boot.logging.LoggingApplicationListener
+org.springframework.boot.context.logging.ClasspathLoggingApplicationListener,\
+org.springframework.boot.context.logging.LoggingApplicationListener,\
+org.springframework.boot.liquibase.LiquibaseServiceLocatorApplicationListener
 
 # Environment Post Processors
 org.springframework.boot.env.EnvironmentPostProcessor=\

spring-boot/src/test/java/org/springframework/boot/logging/LoggingApplicationListenerIntegrationTests.java → spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerIntegrationTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.logging;
+package org.springframework.boot.context.logging;
 
 import org.junit.Rule;
 import org.junit.Test;
@@ -24,6 +24,7 @@ import org.slf4j.LoggerFactory;
 import org.springframework.boot.WebApplicationType;
 import org.springframework.boot.builder.SpringApplicationBuilder;
 import org.springframework.boot.context.event.ApplicationStartingEvent;
+import org.springframework.boot.logging.LoggingSystem;
 import org.springframework.boot.testutil.InternalOutputCapture;
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.ConfigurableApplicationContext;

spring-boot/src/test/java/org/springframework/boot/logging/LoggingApplicationListenerTests.java → spring-boot/src/test/java/org/springframework/boot/context/logging/LoggingApplicationListenerTests.java

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package org.springframework.boot.logging;
+package org.springframework.boot.context.logging;
 
 import java.io.File;
 import java.io.IOException;
@@ -40,6 +40,12 @@ import org.springframework.boot.ApplicationPid;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.context.event.ApplicationFailedEvent;
 import org.springframework.boot.context.event.ApplicationStartingEvent;
+import org.springframework.boot.logging.AbstractLoggingSystem;
+import org.springframework.boot.logging.LogFile;
+import org.springframework.boot.logging.LogLevel;
+import org.springframework.boot.logging.LoggerConfiguration;
+import org.springframework.boot.logging.LoggingInitializationContext;
+import org.springframework.boot.logging.LoggingSystem;
 import org.springframework.boot.logging.java.JavaLoggingSystem;
 import org.springframework.boot.testutil.InternalOutputCapture;
 import org.springframework.context.ApplicationEvent;