Create LoggingSystem class to configure logging

Add LoggingSystem class that can be used to configure various logging
systems in a consistent way. Mostly the code is migrated from the
LoggingApplicationContextInitializer.

spring-bootstrap/src/main/java/org/springframework/bootstrap/context/initializer/LoggingApplicationContextInitializer.java

@@ -22,17 +22,14 @@ import java.util.Map;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
-import org.springframework.bootstrap.logging.JavaLoggerConfigurer;
-import org.springframework.bootstrap.logging.LogbackConfigurer;
-import org.springframework.context.ApplicationContext;
+import org.springframework.bootstrap.SpringApplication;
+import org.springframework.bootstrap.SpringApplicationInitializer;
+import org.springframework.bootstrap.logging.LoggingSystem;
 import org.springframework.context.ApplicationContextInitializer;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.Ordered;
 import org.springframework.core.env.ConfigurableEnvironment;
 import org.springframework.core.env.Environment;
-import org.springframework.core.io.ClassPathResource;
-import org.springframework.util.ClassUtils;
-import org.springframework.util.Log4jConfigurer;
 import org.springframework.util.ResourceUtils;
 
 /**
@@ -68,7 +65,8 @@ import org.springframework.util.ResourceUtils;
  * @author Phillip Webb
  */
 public class LoggingApplicationContextInitializer implements
-		ApplicationContextInitializer<ConfigurableApplicationContext>, Ordered {
+		ApplicationContextInitializer<ConfigurableApplicationContext>,
+		SpringApplicationInitializer, Ordered {
 
 	private static final Map<String, String> ENVIRONMENT_SYSTEM_PROPERTY_MAPPING;
 	static {
@@ -78,8 +76,16 @@ public class LoggingApplicationContextInitializer implements
 		ENVIRONMENT_SYSTEM_PROPERTY_MAPPING.put("PID", "PID");
 	}
 
+	private final Log logger = LogFactory.getLog(getClass());
+
 	private int order = Integer.MIN_VALUE + 11;
 
+	@Override
+	public void initialize(SpringApplication springApplication) {
+		LoggingSystem.get(springApplication.getClass().getClassLoader())
+				.beforeInitialize();
+	}
+
 	/**
 	 * Initialize the logging system according to preferences expressed through the
 	 * {@link Environment} and the classpath.
@@ -102,7 +108,23 @@ public class LoggingApplicationContextInitializer implements
 		}
 
 		LoggingSystem system = LoggingSystem.get(applicationContext.getClassLoader());
-		system.init(applicationContext);
+
+		// User specified configuration
+		if (environment.containsProperty("logging.config")) {
+			String value = environment.getProperty("logging.config");
+			try {
+				ResourceUtils.getURL(value).openStream().close();
+				system.initialize(value);
+				return;
+			}
+			catch (Exception ex) {
+				// Swallow exception and continue
+			}
+			this.logger.warn("Logging environment value '" + value
+					+ "' cannot be opened and will be ignored");
+		}
+
+		system.initialize();
 	}
 
 	private String getPid() {
@@ -122,113 +144,4 @@ public class LoggingApplicationContextInitializer implements
 		return this.order;
 	}
 
-	private static enum LoggingSystem {
-
-		/**
-		 * Log4J
-		 */
-		LOG4J("org.apache.log4j.PropertyConfigurator", "log4j.xml", "log4j.properties") {
-
-			@Override
-			protected void doInit(ApplicationContext applicationContext,
-					String configLocation) throws Exception {
-				Log4jConfigurer.initLogging(configLocation);
-			}
-		},
-
-		/**
-		 * Logback
-		 */
-		LOGBACK("ch.qos.logback.core.Appender", "logback.xml") {
-
-			@Override
-			protected void doInit(ApplicationContext applicationContext,
-					String configLocation) throws Exception {
-				LogbackConfigurer.initLogging(configLocation);
-			}
-		},
-
-		/**
-		 * Java Util Logging
-		 */
-		JAVA(null, "logging.properties") {
-
-			@Override
-			protected void doInit(ApplicationContext applicationContext,
-					String configLocation) throws Exception {
-				JavaLoggerConfigurer.initLogging(configLocation);
-			}
-		};
-
-		private final Log logger = LogFactory
-				.getLog(LoggingApplicationContextInitializer.class);
-
-		private final String className;
-
-		private final String[] paths;
-
-		private LoggingSystem(String className, String... paths) {
-			this.className = className;
-			this.paths = paths;
-		}
-
-		public void init(ApplicationContext applicationContext) {
-			String configLocation = getConfigLocation(applicationContext);
-			try {
-				doInit(applicationContext, configLocation);
-			}
-			catch (Exception ex) {
-				throw new IllegalStateException("Cannot initialize logging from "
-						+ configLocation, ex);
-			}
-		}
-
-		protected abstract void doInit(ApplicationContext applicationContext,
-				String configLocation) throws Exception;
-
-		private String getConfigLocation(ApplicationContext applicationContext) {
-			Environment environment = applicationContext.getEnvironment();
-			ClassLoader classLoader = applicationContext.getClassLoader();
-
-			// User specified config
-			if (environment.containsProperty("logging.config")) {
-				String value = environment.getProperty("logging.config");
-				try {
-					ResourceUtils.getURL(value).openStream().close();
-					return value;
-				}
-				catch (Exception ex) {
-					// Swallow exception and continue
-				}
-				this.logger.warn("Logging environment value '" + value
-						+ "' cannot be opened and will be ignored");
-			}
-
-			// Common patterns
-			for (String path : this.paths) {
-				ClassPathResource resource = new ClassPathResource(path, classLoader);
-				if (resource.exists()) {
-					return "classpath:" + path;
-				}
-			}
-
-			// Fallback to the default
-			String defaultPath = ClassUtils.getPackageName(JavaLoggerConfigurer.class);
-			defaultPath = defaultPath.replace(".", "/");
-			defaultPath = defaultPath + "/" + this.paths[this.paths.length - 1];
-			return "classpath:" + defaultPath;
-		}
-
-		public static LoggingSystem get(ClassLoader classLoader) {
-			for (LoggingSystem loggingSystem : values()) {
-				String className = loggingSystem.className;
-				if (className == null || ClassUtils.isPresent(className, classLoader)) {
-					return loggingSystem;
-				}
-			}
-			return JAVA;
-		}
-
-	}
-
 }

spring-bootstrap/src/main/java/org/springframework/bootstrap/logging/AbstractLoggingSystem.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright 2012-2013 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.
+ */
+
+package org.springframework.bootstrap.logging;
+
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.util.ClassUtils;
+
+/**
+ * Abstract base class for {@link LoggingSystem} implementations.
+ * 
+ * @author Phillip Webb
+ * @author Dave Syer
+ */
+abstract class AbstractLoggingSystem extends LoggingSystem {
+
+	private final ClassLoader classLoader;
+
+	private final String[] paths;
+
+	public AbstractLoggingSystem(ClassLoader classLoader, String... paths) {
+		this.classLoader = classLoader;
+		this.paths = paths.clone();
+	}
+
+	protected final ClassLoader getClassLoader() {
+		return this.classLoader;
+	}
+
+	@Override
+	public void beforeInitialize() {
+		initializeWithSensibleDefaults();
+	}
+
+	@Override
+	public void initialize() {
+		for (String path : this.paths) {
+			ClassPathResource resource = new ClassPathResource(path, this.classLoader);
+			if (resource.exists()) {
+				initialize("classpath:" + path);
+				return;
+			}
+		}
+		initializeWithSensibleDefaults();
+	}
+
+	protected void initializeWithSensibleDefaults() {
+		initialize(getPackagedConfigFile(this.paths[this.paths.length - 1]));
+	}
+
+	protected final String getPackagedConfigFile(String fileName) {
+		String defaultPath = ClassUtils.getPackageName(getClass());
+		defaultPath = defaultPath.replace(".", "/");
+		defaultPath = defaultPath + "/" + fileName;
+		defaultPath = "classpath:" + defaultPath;
+		return defaultPath;
+	}
+
+}

spring-bootstrap/src/main/java/org/springframework/bootstrap/logging/JavaLoggingSystem.java

@@ -16,7 +16,6 @@
 
 package org.springframework.bootstrap.logging;
 
-import java.io.FileNotFoundException;
 import java.util.logging.LogManager;
 import java.util.logging.Logger;
 
@@ -24,29 +23,27 @@ import org.springframework.util.ResourceUtils;
 import org.springframework.util.SystemPropertyUtils;
 
 /**
- * Logging initializer for {@link Logger java.util.logging}.
+ * {@link LoggingSystem} for {@link Logger java.util.logging}.
  * 
+ * @author Phillip Webb
  * @author Dave Syer
  */
-public abstract class JavaLoggerConfigurer {
+class JavaLoggingSystem extends AbstractLoggingSystem {
 
-	/**
-	 * Configure the logging system from the specified location (a properties file).
-	 * 
-	 * @param location the location to use to configure logging
-	 */
-	public static void initLogging(String location) throws FileNotFoundException {
-		String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(location);
+	public JavaLoggingSystem(ClassLoader classLoader) {
+		super(classLoader, "logging.properties");
+	}
+
+	@Override
+	public void initialize(String configLocation) {
+		String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(configLocation);
 		try {
 			LogManager.getLogManager().readConfiguration(
 					ResourceUtils.getURL(resolvedLocation).openStream());
 		}
 		catch (Exception ex) {
-			if (ex instanceof FileNotFoundException) {
-				throw (FileNotFoundException) ex;
-			}
-			throw new IllegalArgumentException("Could not initialize logging from "
-					+ location, ex);
+			throw new IllegalStateException("Could not initialize logging from "
+					+ configLocation, ex);
 		}
 	}
 

spring-bootstrap/src/main/java/org/springframework/bootstrap/logging/Log4JLoggingSystem.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2012-2013 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.
+ */
+
+package org.springframework.bootstrap.logging;
+
+import org.springframework.util.Log4jConfigurer;
+
+/**
+ * {@link LoggingSystem} for for <a href="http://logging.apache.org/log4j">log4j</a>.
+ * 
+ * @author Phillip Webb
+ * @author Dave Syer
+ */
+class Log4JLoggingSystem extends AbstractLoggingSystem {
+
+	public Log4JLoggingSystem(ClassLoader classLoader) {
+		super(classLoader, "log4j.xml", "log4j.properties");
+	}
+
+	@Override
+	public void initialize(String configLocation) {
+		try {
+			Log4jConfigurer.initLogging(configLocation);
+		}
+		catch (Exception ex) {
+			throw new IllegalStateException("Could not initialize logging from "
+					+ configLocation, ex);
+		}
+	}
+
+}

spring-bootstrap/src/main/java/org/springframework/bootstrap/logging/LogbackLoggingSystem.java

@@ -16,41 +16,43 @@
 
 package org.springframework.bootstrap.logging;
 
-import java.io.FileNotFoundException;
 import java.net.URL;
 
+import org.slf4j.ILoggerFactory;
 import org.slf4j.impl.StaticLoggerBinder;
+import org.springframework.util.Assert;
 import org.springframework.util.ResourceUtils;
 import org.springframework.util.SystemPropertyUtils;
 
 import ch.qos.logback.classic.LoggerContext;
 import ch.qos.logback.classic.util.ContextInitializer;
-import ch.qos.logback.core.joran.spi.JoranException;
 
 /**
- * Logging initializer for <a href="http://logback.qos.ch">logback</a>.
+ * {@link LoggingSystem} for for <a href="http://logback.qos.ch">logback</a>.
  * 
+ * @author Phillip Webb
  * @author Dave Syer
  */
-public abstract class LogbackConfigurer {
+class LogbackLoggingSystem extends AbstractLoggingSystem {
 
-	/**
-	 * Configure the logback system from the specified location.
-	 * 
-	 * @param location the location to use to configure logback
-	 */
-	public static void initLogging(String location) throws FileNotFoundException {
-		String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(location);
-		URL url = ResourceUtils.getURL(resolvedLocation);
-		LoggerContext context = (LoggerContext) StaticLoggerBinder.getSingleton()
-				.getLoggerFactory();
+	public LogbackLoggingSystem(ClassLoader classLoader) {
+		super(classLoader, "logback.xml");
+	}
+
+	@Override
+	public void initialize(String configLocation) {
+		String resolvedLocation = SystemPropertyUtils.resolvePlaceholders(configLocation);
+		ILoggerFactory factory = StaticLoggerBinder.getSingleton().getLoggerFactory();
+		Assert.isInstanceOf(ILoggerFactory.class, factory);
+		LoggerContext context = (LoggerContext) factory;
 		context.stop();
 		try {
+			URL url = ResourceUtils.getURL(resolvedLocation);
 			new ContextInitializer(context).configureByResource(url);
 		}
-		catch (JoranException ex) {
-			throw new IllegalArgumentException("Could not initialize logging from "
-					+ location, ex);
+		catch (Exception ex) {
+			throw new IllegalStateException("Could not initialize logging from "
+					+ configLocation, ex);
 		}
 	}
 

spring-bootstrap/src/main/java/org/springframework/bootstrap/logging/LoggingSystem.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2012-2013 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.
+ */
+
+package org.springframework.bootstrap.logging;
+
+import org.springframework.util.ClassUtils;
+
+/**
+ * Common abstraction over logging systems.
+ * 
+ * @author Phillip Webb
+ * @author Dave Syer
+ */
+public abstract class LoggingSystem {
+
+	/**
+	 * Reset the logging system to be limit output. This method may be called before
+	 * {@link #initialize()} to reduce logging noise until the systems has been full
+	 * Initialized.
+	 */
+	public abstract void beforeInitialize();
+
+	/**
+	 * Initialize the logging system using sensible defaults. This method should generally
+	 * try to find system specific configuration on classpath before falling back to
+	 * sensible defaults.
+	 */
+	public abstract void initialize();
+
+	/**
+	 * Initialize the logging system from a logging configuration location.
+	 * @param configLocation a log configuration location
+	 */
+	public abstract void initialize(String configLocation);
+
+	/**
+	 * Detect and return the logging system in use.
+	 * @return The logging system
+	 */
+	public static LoggingSystem get(ClassLoader classLoader) {
+		if (ClassUtils.isPresent("ch.qos.logback.core.Appender", classLoader)) {
+			return new LogbackLoggingSystem(classLoader);
+		}
+		if (ClassUtils.isPresent("org.apache.log4j.PropertyConfigurator", classLoader)) {
+			return new Log4JLoggingSystem(classLoader);
+		}
+		return new JavaLoggingSystem(classLoader);
+	}
+
+}

spring-bootstrap/src/test/java/org/springframework/bootstrap/logging/JavaLoggerSystemTests.java

@@ -17,7 +17,6 @@
 package org.springframework.bootstrap.logging;
 
 import java.io.ByteArrayOutputStream;
-import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.PrintStream;
 import java.util.logging.LogManager;
@@ -30,11 +29,14 @@ import org.junit.Test;
 import static org.junit.Assert.assertTrue;
 
 /**
- * Tests for {@link JavaLoggerConfigurer}.
+ * Tests for {@link JavaLoggingSystem}.
  * 
  * @author Dave Syer
  */
-public class JavaLoggerConfigurerTests {
+public class JavaLoggerSystemTests {
+
+	private JavaLoggingSystem loggingSystem = new JavaLoggingSystem(getClass()
+			.getClassLoader());
 
 	private PrintStream savedOutput;
 
@@ -67,21 +69,21 @@ public class JavaLoggerConfigurerTests {
 
 	@Test
 	public void testDefaultConfigLocation() throws Exception {
-		JavaLoggerConfigurer.initLogging("classpath:logging-nondefault.properties");
+		this.loggingSystem.initialize("classpath:logging-nondefault.properties");
 		this.logger.info("Hello world");
 		String output = getOutput().trim();
 		assertTrue("Wrong output:\n" + output, output.contains("Hello world"));
 		assertTrue("Wrong output:\n" + output, output.contains("INFO"));
 	}
 
-	@Test(expected = FileNotFoundException.class)
+	@Test(expected = IllegalStateException.class)
 	public void testNonexistentConfigLocation() throws Exception {
-		JavaLoggerConfigurer.initLogging("classpath:logging-nonexistent.properties");
+		this.loggingSystem.initialize("classpath:logging-nonexistent.properties");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testNullConfigLocation() throws Exception {
-		JavaLoggerConfigurer.initLogging(null);
+		this.loggingSystem.initialize(null);
 	}
 
 }

spring-bootstrap/src/test/java/org/springframework/bootstrap/logging/LogbackLoggingSystemTests.java

@@ -17,7 +17,6 @@
 package org.springframework.bootstrap.logging;
 
 import java.io.ByteArrayOutputStream;
-import java.io.FileNotFoundException;
 import java.io.PrintStream;
 
 import org.apache.commons.logging.Log;
@@ -29,13 +28,17 @@ import org.junit.Test;
 import static org.junit.Assert.assertTrue;
 
 /**
- * Tests for {@link LogbackConfigurer}.
+ * Tests for {@link LogbackLoggingSystem}.
  * 
  * @author Dave Syer
  */
-public class LogbackConfigurerTests {
+public class LogbackLoggingSystemTests {
+
+	private LogbackLoggingSystem loggingSystem = new LogbackLoggingSystem(getClass()
+			.getClassLoader());
 
 	private PrintStream savedOutput;
+
 	private ByteArrayOutputStream output;
 
 	@Before
@@ -59,22 +62,22 @@ public class LogbackConfigurerTests {
 
 	@Test
 	public void testDefaultConfigLocation() throws Exception {
-		LogbackConfigurer.initLogging("classpath:logback-nondefault.xml");
-		Log logger = LogFactory.getLog(LogbackConfigurerTests.class);
+		this.loggingSystem.initialize("classpath:logback-nondefault.xml");
+		Log logger = LogFactory.getLog(LogbackLoggingSystemTests.class);
 		logger.info("Hello world");
 		String output = getOutput().trim();
 		assertTrue("Wrong output:\n" + output, output.contains("Hello world"));
 		assertTrue("Wrong output:\n" + output, output.startsWith("/tmp/spring.log"));
 	}
 
-	@Test(expected = FileNotFoundException.class)
+	@Test(expected = IllegalStateException.class)
 	public void testNonexistentConfigLocation() throws Exception {
-		LogbackConfigurer.initLogging("classpath:logback-nonexistent.xml");
+		this.loggingSystem.initialize("classpath:logback-nonexistent.xml");
 	}
 
 	@Test(expected = IllegalArgumentException.class)
 	public void testNullConfigLocation() throws Exception {
-		LogbackConfigurer.initLogging(null);
+		this.loggingSystem.initialize(null);
 	}
 
 }

spring-bootstrap/src/test/java/org/springframework/bootstrap/logging/LoggingApplicationContextInitializerTests.java

@@ -26,7 +26,9 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.commons.logging.impl.SLF4JLogFactory;
 import org.junit.After;
 import org.junit.Before;
+import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.TemporaryFolder;
 import org.springframework.bootstrap.context.initializer.LoggingApplicationContextInitializer;
 import org.springframework.context.support.GenericApplicationContext;
 import org.springframework.core.env.PropertySource;
@@ -41,6 +43,9 @@ import static org.junit.Assert.assertTrue;
  */
 public class LoggingApplicationContextInitializerTests {
 
+	@Rule
+	public TemporaryFolder temporaryFolder = new TemporaryFolder();
+
 	private LoggingApplicationContextInitializer initializer = new LoggingApplicationContextInitializer();
 
 	private Log logger = new SLF4JLogFactory().getInstance(getClass());
@@ -130,7 +135,7 @@ public class LoggingApplicationContextInitializerTests {
 						}
 						if ("logging.file".equals(name)) {
 							return "foo.log";
-						}
+						}						
 						return null;
 					}
 				});