ClassLoaderLogManager

/**
* Per classloader LogManager implementation.
*/
public class ClassLoaderLogManager extends LogManager {

private final class Cleaner extends Thread {

@Override
public void run() {
if (useShutdownHook) {
shutdown();
}
}

}


// ------------------------------------------------------------Constructors

public ClassLoaderLogManager() {
super();
try {
Runtime.getRuntime().addShutdownHook(new Cleaner());
} catch (IllegalStateException ise) {
// We are probably already being shutdown. Ignore this error.
}
}


// -------------------------------------------------------------- Variables


/**
* Map containing the classloader information, keyed per classloader. A
* weak hashmap is used to ensure no classloader reference is leaked from
* application redeployment.
*/
protected final Map<ClassLoader, ClassLoaderLogInfo> classLoaderLoggers =
new WeakHashMap<ClassLoader, ClassLoaderLogInfo>();


/**
* This prefix is used to allow using prefixes for the properties names
* of handlers and their subcomponents.
*/
protected ThreadLocal<String> prefix = new ThreadLocal<String>();


/**
* Determines if the shutdown hook is used to perform any necessary
* clean-up such as flushing buffered handlers on JVM shutdown. Defaults to
* <code>true</code> but may be set to false if another component ensures
* that {@link #shutdown()} is called.
*/
protected volatile boolean useShutdownHook = true;


// ------------------------------------------------------------- Properties


public boolean isUseShutdownHook() {
return useShutdownHook;
}


public void setUseShutdownHook(boolean useShutdownHook) {
this.useShutdownHook = useShutdownHook;
}


// --------------------------------------------------------- Public Methods


/**
* Add the specified logger to the classloader local configuration.
*
* @param logger The logger to be added
*/
@Override
public synchronized boolean addLogger(final Logger logger) {

final String loggerName = logger.getName();

ClassLoader classLoader =
Thread.currentThread().getContextClassLoader();
ClassLoaderLogInfo info = getClassLoaderInfo(classLoader);
if (info.loggers.containsKey(loggerName)) {
return false;
}
info.loggers.put(loggerName, logger);

// Apply initial level for new logger
final String levelString = getProperty(loggerName + ".level");
if (levelString != null) {
try {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
logger.setLevel(Level.parse(levelString.trim()));
return null;
}
});
} catch (IllegalArgumentException e) {
// Leave level set to null
}
}

// Always instantiate parent loggers so that
// we can control log categories even during runtime
int dotIndex = loggerName.lastIndexOf('.');
while (dotIndex >= 0) {
final String parentName = loggerName.substring(0, dotIndex);
Logger.getLogger(parentName);
dotIndex = loggerName.lastIndexOf('.', dotIndex - 1);
}

// Find associated node
LogNode node = info.rootNode.findNode(loggerName);
node.logger = logger;

// Set parent logger
Logger parentLogger = node.findParentLogger();
if (parentLogger != null) {
doSetParentLogger(logger, parentLogger);
}

// Tell children we are their new parent
node.setParentLogger(logger);

// Add associated handlers, if any are defined using the .handlers property.
// In this case, handlers of the parent logger(s) will not be used
String handlers = getProperty(loggerName + ".handlers");
if (handlers != null) {
logger.setUseParentHandlers(false);
StringTokenizer tok = new StringTokenizer(handlers, ",");
while (tok.hasMoreTokens()) {
String handlerName = (tok.nextToken().trim());
Handler handler = null;
ClassLoader current = classLoader;
while (current != null) {
info = classLoaderLoggers.get(current);
if (info != null) {
handler = info.handlers.get(handlerName);
if (handler != null) {
break;
}
}
current = current.getParent();
}
if (handler != null) {
logger.addHandler(handler);
}
}
}

// Parse useParentHandlers to set if the logger should delegate to its parent.
// Unlike java.util.logging, the default is to not delegate if a list of handlers
// has been specified for the logger.
String useParentHandlersString = getProperty(loggerName + ".useParentHandlers");
if (Boolean.valueOf(useParentHandlersString).booleanValue()) {
logger.setUseParentHandlers(true);
}

return true;
}


/**
* Get the logger associated with the specified name inside
* the classloader local configuration. If this returns null,
* and the call originated for Logger.getLogger, a new
* logger with the specified name will be instantiated and
* added using addLogger.
*
* @param name The name of the logger to retrieve
*/
@Override
public synchronized Logger getLogger(final String name) {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
return getClassLoaderInfo(classLoader).loggers.get(name);
}


/**
* Get an enumeration of the logger names currently defined in the
* classloader local configuration.
*/
@Override
public synchronized Enumeration<String> getLoggerNames() {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
return Collections.enumeration(getClassLoaderInfo(classLoader).loggers.keySet());
}


/**
* Get the value of the specified property in the classloader local
* configuration.
*
* @param name The property name
*/
@Override
public String getProperty(String name) {
ClassLoader classLoader = Thread.currentThread()
.getContextClassLoader();
String prefix = this.prefix.get();
if (prefix != null) {
name = prefix + name;
}
ClassLoaderLogInfo info = getClassLoaderInfo(classLoader);
String result = info.props.getProperty(name);
// If the property was not found, and the current classloader had no
// configuration (property list is empty), look for the parent classloader
// properties.
if ((result == null) && (info.props.isEmpty())) {
ClassLoader current = classLoader.getParent();
while (current != null) {
info = classLoaderLoggers.get(current);
if (info != null) {
result = info.props.getProperty(name);
if ((result != null) || (!info.props.isEmpty())) {
break;
}
}
current = current.getParent();
}
if (result == null) {
result = super.getProperty(name);
}
}
// Simple property replacement (mostly for folder names)
if (result != null) {
result = replace(result);
}
return result;
}


@Override
public void readConfiguration()
throws IOException, SecurityException {

checkAccess();

readConfiguration(Thread.currentThread().getContextClassLoader());

}

@Override
public void readConfiguration(InputStream is)
throws IOException, SecurityException {

checkAccess();
reset();

readConfiguration(is, Thread.currentThread().getContextClassLoader());

}

@Override
public void reset() throws SecurityException {
Thread thread = Thread.currentThread();
if (thread.getClass().getName().startsWith(
"java.util.logging.LogManager$")) {
// Ignore the call from java.util.logging.LogManager.Cleaner,
// because we have our own shutdown hook
return;
}
ClassLoader classLoader = thread.getContextClassLoader();
ClassLoaderLogInfo clLogInfo = getClassLoaderInfo(classLoader);
resetLoggers(clLogInfo);
super.reset();
}

/**
* Shuts down the logging system.
*/
public void shutdown() {
// The JVM is being shutdown. Make sure all loggers for all class
// loaders are shutdown
for (ClassLoaderLogInfo clLogInfo : classLoaderLoggers.values()) {
resetLoggers(clLogInfo);
}
}

// -------------------------------------------------------- Private Methods
private void resetLoggers(ClassLoaderLogInfo clLogInfo) {
// This differs from LogManager#resetLogger() in that we close not all
// handlers of all loggers, but only those that are present in our
// ClassLoaderLogInfo#handlers list. That is because our #addLogger(..)
// method can use handlers from the parent class loaders, and closing
// handlers that the current class loader does not own would be not
// good.
synchronized (clLogInfo) {
for (Logger logger : clLogInfo.loggers.values()) {
Handler[] handlers = logger.getHandlers();
for (Handler handler : handlers) {
logger.removeHandler(handler);
}
}
for (Handler handler : clLogInfo.handlers.values()) {
try {
handler.close();
} catch (Exception e) {
// Ignore
}
}
clLogInfo.handlers.clear();
}
}

// ------------------------------------------------------ Protected Methods


/**
* Retrieve the configuration associated with the specified classloader. If
* it does not exist, it will be created.
*
* @param classLoader The classloader for which we will retrieve or build the
* configuration
*/
protected ClassLoaderLogInfo getClassLoaderInfo(ClassLoader classLoader) {

if (classLoader == null) {
classLoader = ClassLoader.getSystemClassLoader();
}
ClassLoaderLogInfo info = classLoaderLoggers.get(classLoader);
if (info == null) {
final ClassLoader classLoaderParam = classLoader;
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
try {
readConfiguration(classLoaderParam);
} catch (IOException e) {
// Ignore
}
return null;
}
});
info = classLoaderLoggers.get(classLoader);
}
return info;
}


/**
* Read configuration for the specified classloader.
*
* @param classLoader
* @throws IOException Error
*/
protected void readConfiguration(ClassLoader classLoader)
throws IOException {

InputStream is = null;
// Special case for URL classloaders which are used in containers:
// only look in the local repositories to avoid redefining loggers 20 times
try {
if ((classLoader instanceof URLClassLoader)
&& (((URLClassLoader) classLoader).findResource("logging.properties") != null)) {
is = classLoader.getResourceAsStream("logging.properties");
}
} catch (AccessControlException ace) {
// No permission to configure logging in context
// Log and carry on
ClassLoaderLogInfo info = classLoaderLoggers.get(ClassLoader.getSystemClassLoader());
if (info != null) {
Logger log = info.loggers.get("");
if (log != null) {
Permission perm = ace.getPermission();
if (perm instanceof FilePermission && perm.getActions().equals("read")) {
log.warning("Reading " + perm.getName() + " is not permitted. See \"per context logging\" in the default catalina.policy file.");
}
else {
log.warning("Reading logging.properties is not permitted in some context. See \"per context logging\" in the default catalina.policy file.");
log.warning("Original error was: " + ace.getMessage());
}
}
}
}
if ((is == null) && (classLoader == ClassLoader.getSystemClassLoader())) {
String configFileStr = System.getProperty("java.util.logging.config.file");
if (configFileStr != null) {
try {
is = new FileInputStream(replace(configFileStr));
} catch (IOException e) {
// Ignore
}
}
// Try the default JVM configuration
if (is == null) {
File defaultFile = new File(new File(System.getProperty("java.home"), "lib"),
"logging.properties");
try {
is = new FileInputStream(defaultFile);
} catch (IOException e) {
// Critical problem, do something ...
}
}
}

Logger localRootLogger = new RootLogger();
if (is == null) {
// Retrieve the root logger of the parent classloader instead
ClassLoader current = classLoader.getParent();
ClassLoaderLogInfo info = null;
while (current != null && info == null) {
info = getClassLoaderInfo(current);
current = current.getParent();
}
if (info != null) {
localRootLogger.setParent(info.rootNode.logger);
}
}
ClassLoaderLogInfo info =
new ClassLoaderLogInfo(new LogNode(null, localRootLogger));
classLoaderLoggers.put(classLoader, info);

if (is != null) {
readConfiguration(is, classLoader);
}
addLogger(localRootLogger);

}


/**
* Load specified configuration.
*
* @param is InputStream to the properties file
* @param classLoader for which the configuration will be loaded
* @throws IOException If something wrong happens during loading
*/
protected void readConfiguration(InputStream is, ClassLoader classLoader)
throws IOException {

ClassLoaderLogInfo info = classLoaderLoggers.get(classLoader);

try {
info.props.load(is);
} catch (IOException e) {
// Report error
System.err.println("Configuration error");
e.printStackTrace();
} finally {
try {
is.close();
} catch (Throwable t) {}
}

// Create handlers for the root logger of this classloader
String rootHandlers = info.props.getProperty(".handlers");
String handlers = info.props.getProperty("handlers");
Logger localRootLogger = info.rootNode.logger;
if (handlers != null) {
StringTokenizer tok = new StringTokenizer(handlers, ",");
while (tok.hasMoreTokens()) {
String handlerName = (tok.nextToken().trim());
String handlerClassName = handlerName;
String prefix = "";
if (handlerClassName.length() <= 0) {
continue;
}
// Parse and remove a prefix (prefix start with a digit, such as
// "10WebappFooHanlder.")
if (Character.isDigit(handlerClassName.charAt(0))) {
int pos = handlerClassName.indexOf('.');
if (pos >= 0) {
prefix = handlerClassName.substring(0, pos + 1);
handlerClassName = handlerClassName.substring(pos + 1);
}
}
try {
this.prefix.set(prefix);
Handler handler =
(Handler) classLoader.loadClass(handlerClassName).newInstance();
// The specification strongly implies all configuration should be done
// during the creation of the handler object.
// This includes setting level, filter, formatter and encoding.
this.prefix.set(null);
info.handlers.put(handlerName, handler);
if (rootHandlers == null) {
localRootLogger.addHandler(handler);
}
} catch (Exception e) {
// Report error
System.err.println("Handler error");
e.printStackTrace();
}
}

}

}


/**
* Set parent child relationship between the two specified loggers.
*
* @param logger
* @param parent
*/
protected static void doSetParentLogger(final Logger logger,
final Logger parent) {
AccessController.doPrivileged(new PrivilegedAction<Object>() {
public Object run() {
logger.setParent(parent);
return null;
}
});
}


/**
* System property replacement in the given string.
*
* @param str The original string
* @return the modified string
*/
protected String replace(String str) {
String result = str;
int pos_start = result.indexOf("${");
if (pos_start != -1) {
int pos_end = result.indexOf('}');
if (pos_end != -1) {
String propName = result.substring(pos_start + 2, pos_end);
String replacement = System.getProperty(propName);
if (replacement != null) {
if(pos_start >0) {
result = result.substring(0,pos_start) +
replacement + replace(result.substring(pos_end + 1));
} else {
result = replacement + replace(result.substring(pos_end + 1));
}
}
}
}
return result;
}


// ---------------------------------------------------- LogNode Inner Class


protected static final class LogNode {
Logger logger;

protected final Map<String, LogNode> children =
new HashMap<String, LogNode>();

protected final LogNode parent;

LogNode(final LogNode parent, final Logger logger) {
this.parent = parent;
this.logger = logger;
}

LogNode(final LogNode parent) {
this(parent, null);
}

LogNode findNode(String name) {
LogNode currentNode = this;
if (logger.getName().equals(name)) {
return this;
}
while (name != null) {
final int dotIndex = name.indexOf('.');
final String nextName;
if (dotIndex < 0) {
nextName = name;
name = null;
} else {
nextName = name.substring(0, dotIndex);
name = name.substring(dotIndex + 1);
}
LogNode childNode = currentNode.children.get(nextName);
if (childNode == null) {
childNode = new LogNode(currentNode);
currentNode.children.put(nextName, childNode);
}
currentNode = childNode;
}
return currentNode;
}

Logger findParentLogger() {
Logger logger = null;
LogNode node = parent;
while (node != null && logger == null) {
logger = node.logger;
node = node.parent;
}
return logger;
}

void setParentLogger(final Logger parent) {
for (final Iterator<LogNode> iter =
children.values().iterator(); iter.hasNext();) {
final LogNode childNode = iter.next();
if (childNode.logger == null) {
childNode.setParentLogger(parent);
} else {
doSetParentLogger(childNode.logger, parent);
}
}
}

}


// -------------------------------------------- ClassLoaderInfo Inner Class


protected static final class ClassLoaderLogInfo {
final LogNode rootNode;
final Map<String, Logger> loggers = new HashMap<String, Logger>();
final Map<String, Handler> handlers = new HashMap<String, Handler>();
final Properties props = new Properties();

ClassLoaderLogInfo(final LogNode rootNode) {
this.rootNode = rootNode;
}

}


// ------------------------------------------------- RootLogger Inner Class


/**
* This class is needed to instantiate the root of each per classloader
* hierarchy.
*/
protected class RootLogger extends Logger {
public RootLogger() {
super("", null);
}
}


}