WaarpLoggerFactory.java

/*
 * Copyright 2012 The Netty Project
 * The Netty Project 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.waarp.common.logging;

import io.netty.util.internal.logging.InternalLoggerFactory;
import io.netty.util.internal.logging.JdkLoggerFactory;
import io.netty.util.internal.logging.Slf4JLoggerFactory;

/**
 * Creates an {@link WaarpLogger} or changes the default factory
 * implementation. This factory allows you to choose what logging framework
 * VITAM should use. The default factory is {@link WaarpSlf4JLoggerFactory}. If SLF4J
 * is not available, {@link WaarpSlf4JLoggerFactory} is used. If Log4J is not available, {@link WaarpJdkLoggerFactory} is used. You can
 * change it to your preferred
 * logging framework before other VITAM classes are loaded:
 *
 * <pre>
 * {@link WaarpLoggerFactory}.setDefaultFactory(new {@link WaarpSlf4JLoggerFactory}());
 * </pre>
 *
 * Please note that the new default factory is effective only for the classes
 * which were loaded after the default factory is changed. Therefore, {@link #setDefaultFactory(WaarpLoggerFactory)} should be
 * called as early
 * as possible and shouldn't be called more than once.
 */
public abstract class WaarpLoggerFactory {
    private static volatile WaarpLoggerFactory defaultFactory;
    protected static WaarpLogLevel currentLevel = null;

    static {
        final String name = WaarpLoggerFactory.class.getName();
        WaarpLoggerFactory f;
        try {
            f = new WaarpSlf4JLoggerFactory(true);
            f.newInstance(name).debug("Using Logback (SLF4J) as the default logging framework");
            defaultFactory = f;
        } catch (final Throwable t1) {
            f = new WaarpJdkLoggerFactory(null);
            f.newInstance(name).debug("Using java.util.logging as the default logging framework", t1);
        }

        defaultFactory = f;
    }

    /**
     * Returns the default factory. The initial default factory is {@link WaarpJdkLoggerFactory}.
     *
     * @return the current default Factory
     */
    public static WaarpLoggerFactory getDefaultFactory() {
        return defaultFactory;
    }

    /**
     * Changes the default factory.
     *
     * @param defaultFactory
     */
    public static void setDefaultFactory(final WaarpLoggerFactory defaultFactory) {
        if (defaultFactory == null) {
            throw new NullPointerException("defaultFactory");
        }
        WaarpLoggerFactory.defaultFactory = defaultFactory;
        if (defaultFactory instanceof WaarpJdkLoggerFactory) {
            InternalLoggerFactory.setDefaultFactory(new JdkLoggerFactory());
        } else if (defaultFactory instanceof WaarpSlf4JLoggerFactory) {
            InternalLoggerFactory.setDefaultFactory(new Slf4JLoggerFactory());
        }
        defaultFactory.seLevelSpecific(defaultFactory.getLevelSpecific());
    }

    /**
     * Creates a new logger instance with the name of the specified class.
     *
     * @param clazz
     * @return the logger instance
     */
    public static WaarpLogger getInstance(final Class<?> clazz) {
        return getInstance(clazz.getName());
    }

    /**
     * Creates a new logger instance with the specified name.
     *
     * @param name
     * @return the logger instance
     */
    public static WaarpLogger getInstance(final String name) {
        return getDefaultFactory().newInstance(name);
    }

    /**
     * Creates a new logger instance with the name of the specified class.
     *
     * @param clazz
     * @return the logger instance
     */
    public static WaarpLogger getLogger(final Class<?> clazz) {
        return getInstance(clazz.getName());
    }

    /**
     * Creates a new logger instance with the specified name.
     *
     * @param name
     * @return the logger instance
     */
    public static WaarpLogger getLogger(final String name) {
        return getDefaultFactory().newInstance(name);
    }

    /**
     * @param level
     */
    public static void setLogLevel(final WaarpLogLevel level) {
        setInternalLogLevel(level);
        if (currentLevel != null) {
            getDefaultFactory().seLevelSpecific(currentLevel);
        }
    }

    public static WaarpLogLevel getLogLevel() {
        return currentLevel;
    }

    protected static synchronized void setInternalLogLevel(final WaarpLogLevel level) {
        if (level != null) {
            currentLevel = level;
        }
    }

    /**
     * @param level
     */
    public WaarpLoggerFactory(final WaarpLogLevel level) {
        setInternalLogLevel(level);
        if (currentLevel == null) {
            setInternalLogLevel(getLevelSpecific());
        }
    }

    /**
     *
     * @return should return the current Level for the specific implementation
     */
    protected abstract WaarpLogLevel getLevelSpecific();

    /**
     * Set the level for the specific implementation
     *
     * @param level
     */
    protected abstract void seLevelSpecific(WaarpLogLevel level);

    /**
     * Creates a new logger instance with the specified name.
     */
    protected abstract WaarpLogger newInstance(String name);
}