LoggerCreator.java

/*
 * 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.openejb.log;

import org.apache.openejb.core.ParentClassLoaderFinder;
import org.apache.openejb.loader.SystemInstance;

import java.util.Properties;
import java.util.concurrent.Callable;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.logging.Handler;
import java.util.logging.Level;
import java.util.logging.Logger;

public class LoggerCreator implements Callable<Logger> {
    private final String name;
    private Logger logger;
    private volatile boolean init;

    public LoggerCreator(final String channel) {
        name = channel;

        // force eager init if config overrided
        final Properties p = SystemInstance.get().getProperties();
        final String levelName = p.getProperty("logging.level." + channel);
        if (levelName != null) {
            try {
                call();
            } catch (final Exception e) {
                // no-op
            }
        }
    }

    @Override
    public Logger call() throws Exception {
        if (logger == null) {
            synchronized (this) { // no need of lock for this part
                if (logger == null) {
                    final Thread thread = Thread.currentThread();
                    final ClassLoader originalLoader = thread.getContextClassLoader();
                    thread.setContextClassLoader(ParentClassLoaderFinder.Helper.get());
                    try {
                        try {
                            logger = Logger.getLogger(name);
                        } catch (final Exception e) {
                            logger = Logger.getLogger(name); // try again
                        }

                        // if level set through properties force it
                        final Properties p = SystemInstance.get().getProperties();
                        final String levelName = p.getProperty("logging.level." + logger.getName());
                        if (levelName != null) {
                            final Level level = Level.parse(levelName);
                            for (final Handler handler : logger.getHandlers()) {
                                handler.setLevel(level);
                            }
                        }
                    } finally {
                        thread.setContextClassLoader(originalLoader);
                    }
                }
            }
        }
        return logger;
    }

    public boolean isInit() {
        return init;
    }

    public static final class Get {
        private Get() {
            // no-op
        }

        private static Logger exec(final LoggerCreator creator) {
            final ClassLoader old = Thread.currentThread().getContextClassLoader();
            Thread.currentThread().setContextClassLoader(ParentClassLoaderFinder.Helper.get());
            try {
                return creator.call();
            } catch (final Exception e) { // shouldn't occur regarding the impl we use
                return Logger.getLogger("default");
            } finally {
                Thread.currentThread().setContextClassLoader(old);
            }
        }

        public static Logger exec(final LoggerCreator logger, final AtomicBoolean debug, final AtomicBoolean info) {
            final Logger l = exec(logger);
            if (!logger.init) {
                levels(logger, debug, info);
            }
            return l;
        }

        public static void levels(final LoggerCreator lc, final AtomicBoolean debug, final AtomicBoolean info) {
            if (lc.init) {
                return;
            }

            final Logger l;
            try {
                l = lc.call();
            } catch (final Exception e) {
                return;
            }

            debug.set(l.isLoggable(Level.FINE));
            info.set(l.isLoggable(Level.INFO));
            lc.init = true;
        }
    }
}