package com.atlassian.plugins.rest.module;
   
   import org.slf4j.Logger;
   import org.slf4j.LoggerFactory;
   import org.slf4j.bridge.SLF4JBridgeHandler;
   
   /**
    * Utility class for safely installing and uninstalling the JUL-{@literal >}SLF4J bridge.
    *
   * @see SLF4JBridgeHandler
   */
  public final class Slf4jBridge {
      /**
       * Logger for this class.
       */
      private static final Logger log = LoggerFactory.getLogger(Slf4jBridge.class);
  
      /**
       * Returns a Helper instance that can be used to install/uninstall the JUL-{@literal >}SLF4J bridge. This method tries to
       * reflectively load the class <code>org.slf4j.bridge.SLF4JBridgeHandler</code> before using it, so it is safe to
       * use in an OSGi environment where the class may or may not be present.
       * <p>
       * If the SLF4J bridge is found, then the helper can be used to install and uninstall the bridge in the thread
       * context class loader (TCCL). If the bridge is not found then the helper's operations are no-ops.
       *
       * @return a Helper instance that can be used to install/uninstall the JUL-{@literal >}SLF4J bridge.
       */
      public static Helper createHelper() {
          try {
              Class.forName("org.slf4j.bridge.SLF4JBridgeHandler");
  
              return new BridgePresentHelper();
          } catch (ClassNotFoundException e) {
              return new BridgeMissingHelper();
          }
      }
  
      public interface Helper {
          /**
           * Installs the bridge.
           */
          void install();
  
          /**
           * Un-installs the bridge.
           */
          void uninstall();
  
      }
  
      private static class BridgeMissingHelper implements Helper {
          public void install() {
              log.debug("Skipping installation of SLF4JBridgeHandler for {}. Have you provided jcl-over-slf4j.jar?", Thread.currentThread().getContextClassLoader());
          }
  
          public void uninstall() {
          }
      }
  
      private static class BridgePresentHelper implements Helper {
          public void install() {
              log.debug("Installing SLF4JBridgeHandler for {}.", Thread.currentThread().getContextClassLoader());
              SLF4JBridgeHandler.install();
          }
  
          public void uninstall() {
              SLF4JBridgeHandler.uninstall();
              log.debug("Uninstalled SLF4JBridgeHandler for {}.", Thread.currentThread().getContextClassLoader());
          }
      }
  }