Tomcat example source code file (ClassLoaderLogManager.java)

This example Tomcat source code file (ClassLoaderLogManager.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Tomcat tags/keywords

classloader, classloaderloginfo, classloaderloginfo, handler, io, ioexception, log, logger, logger, logging, lognode, lognode, map, network, object, security, string, string, stringtokenizer, util

The Tomcat ClassLoaderLogManager.java source code

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.juli;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URLClassLoader;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.Collections;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import java.util.StringTokenizer;
import java.util.WeakHashMap;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.LogManager;
import java.util.logging.Logger;


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


    // -------------------------------------------------------------- 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();

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


    /**
     * Add the specified logger to the classloader local configuration.
     * 
     * @param logger The logger to be added
     */
    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() {
                    public Object run() {
                        logger.setLevel(Level.parse(levelString.trim()));
                        return null;
                    }
                });
            } catch (IllegalArgumentException e) {
                // Leave level set to null
            }
        }

        // If any parent loggers have levels definied, make sure they are
        // instantiated
        int dotIndex = loggerName.lastIndexOf('.');
        while (dotIndex >= 0) {
            final String parentName = loggerName.substring(0, dotIndex);
            if (getProperty(parentName + ".level") != null) {
                Logger.getLogger(parentName);
                break;
            }
            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 = (ClassLoaderLogInfo) classLoaderLoggers.get(current);
                    if (info != null) {
                        handler = (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
     */
    public synchronized Logger getLogger(final String name) {
        ClassLoader classLoader = Thread.currentThread()
                .getContextClassLoader();
        return (Logger) getClassLoaderInfo(classLoader).loggers.get(name);
    }
    
    
    /**
     * Get an enumeration of the logger names currently defined in the 
     * classloader local configuration.
     */
    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
     */    
    public String getProperty(String name) {
        ClassLoader classLoader = Thread.currentThread()
            .getContextClassLoader();
        String prefix = (String) 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 = (ClassLoaderLogInfo) 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;
    }
    
    
    public void readConfiguration()
        throws IOException, SecurityException {
        
        checkAccess();
        
        readConfiguration(Thread.currentThread().getContextClassLoader());
        
    }
        
    public void readConfiguration(InputStream is)
        throws IOException, SecurityException {
        
        checkAccess();
        reset();

        readConfiguration(is, Thread.currentThread().getContextClassLoader());
    
    }
        
    // ------------------------------------------------------ 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 = (ClassLoaderLogInfo) classLoaderLoggers
                .get(classLoader);
        if (info == null) {
            final ClassLoader classLoaderParam = classLoader;
            AccessController.doPrivileged(new PrivilegedAction() {
                public Object run() {
                    try {
                        readConfiguration(classLoaderParam);
                    } catch (IOException e) {
                        // Ignore
                    }
                    return null;
                }
            });
            info = (ClassLoaderLogInfo) classLoaderLoggers.get(classLoader);
        }
        return info;
    }

    
    /**
     * Read configuration for the specified classloader.
     * 
     * @param classLoader 
     * @throws IOException Errot
     */
    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
        if ((classLoader instanceof URLClassLoader) 
                && (((URLClassLoader) classLoader).findResource("logging.properties") != null)) {
            is = classLoader.getResourceAsStream("logging.properties");
        }
        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 = 
            (ClassLoaderLogInfo) 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() {
            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 = (LogNode) 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 iter = children.values().iterator(); iter
                    .hasNext();) {
                final LogNode childNode = (LogNode) 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();
        final Map<String, Handler> handlers = new HashMap();
        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);
        }
    }


}