Restructure example

Improve logging

git-svn-id: https://svn.argeo.org/slc/trunk@1261 4cfe0d0a-d680-48aa-b62c-e0a02a3f76cc

diff --git a/org.argeo.slc.core/src/main/java/org/argeo/slc/logging/Log4jUtils.java b/org.argeo.slc.core/src/main/java/org/argeo/slc/logging/Log4jUtils.java
new file mode 100644 (file)
index 0000000..6249c6f
--- /dev/null
+++ b/org.argeo.slc.core/src/main/java/org/argeo/slc/logging/Log4jUtils.java
@@ -0,0 +1,78 @@
+package org.argeo.slc.logging;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Properties;
+
+import org.apache.commons.io.IOUtils;
+import org.apache.log4j.LogManager;
+import org.apache.log4j.PropertyConfigurator;
+import org.argeo.slc.core.SlcException;
+import org.springframework.core.io.DefaultResourceLoader;
+import org.springframework.util.ResourceUtils;
+import org.springframework.util.SystemPropertyUtils;
+
+public class Log4jUtils {
+
+       /**
+        * Configure log4j based on properties, with the following priorities (from
+        * highest to lowest):<br>
+        * 1. System properties<br>
+        * 2. configuration file itself
+        */
+       public static void initLog4j(String configuration) {
+               // clears previous configuration
+               shutDownLog4j();
+
+               ClassLoader cl = Log4jUtils.class.getClassLoader();
+               Properties properties = new Properties();
+               if (configuration != null) {
+                       InputStream in = null;
+                       try {
+                               if (configuration
+                                               .startsWith(ResourceUtils.CLASSPATH_URL_PREFIX)) {
+                                       String path = configuration
+                                                       .substring(ResourceUtils.CLASSPATH_URL_PREFIX
+                                                                       .length());
+                                       in = cl.getResourceAsStream(path);
+                               } else {
+                                       in = new DefaultResourceLoader(cl).getResource(
+                                                       configuration).getInputStream();
+                               }
+
+                               properties.load(in);
+                       } catch (IOException e) {
+                               throw new SlcException("Cannot load properties from "
+                                               + configuration);
+                       } finally {
+                               IOUtils.closeQuietly(in);
+                       }
+               }
+
+               // Overrides with System properties
+               overrideLog4jProperties(properties, System.getProperties());
+
+               PropertyConfigurator.configure(properties);
+       }
+
+       private static void overrideLog4jProperties(Properties target,
+                       Properties additional) {
+               for (String key : additional.stringPropertyNames()) {
+                       if (key.startsWith("log4j.")) {
+                               if (!key.equals("log4j.configuration")) {
+                                       String value = SystemPropertyUtils
+                                                       .resolvePlaceholders(additional.getProperty(key));
+                                       target.put(key, value);
+                               }
+                       }
+               }
+       }
+
+       public static void shutDownLog4j() {
+               LogManager.shutdown();
+       }
+
+       private Log4jUtils() {
+
+       }
+}