/*
 * 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.log4j.spi;

import java.util.Enumeration;

import org.apache.log4j.Appender;
import org.apache.log4j.Category;
import org.apache.log4j.Level;
import org.apache.log4j.Logger;

/**
 * A <code>LoggerRepository</code> is used to create and retrieve
 * <code>Loggers</code>. The relation between loggers in a repository depends on
 * the repository but typically loggers are arranged in a named hierarchy.
 * 
 * <p>
 * In addition to the creational methods, a <code>LoggerRepository</code> can be
 * queried for existing loggers, can act as a point of registry for events
 * related to loggers.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @since 1.2
 */
public interface LoggerRepository {

    /**
     * Add a {@link HierarchyEventListener} event to the repository.
     */
    public void addHierarchyEventListener(HierarchyEventListener listener);

    /**
     * Returns whether this repository is disabled for a given level. The answer
     * depends on the repository threshold and the <code>level</code> parameter. See
     * also {@link #setThreshold} method.
     */
    boolean isDisabled(int level);

    /**
     * Set the repository-wide threshold. All logging requests below the threshold
     * are immediately dropped. By default, the threshold is set to
     * <code>Level.ALL</code> which has the lowest possible rank.
     */
    public void setThreshold(Level level);

    /**
     * Another form of {@link #setThreshold(Level)} accepting a string parameter
     * instead of a <code>Level</code>.
     */
    public void setThreshold(String val);

    public void emitNoAppenderWarning(Category cat);

    /**
     * Get the repository-wide threshold. See {@link #setThreshold(Level)} for an
     * explanation.
     */
    public Level getThreshold();

    public Logger getLogger(String name);

    public Logger getLogger(String name, LoggerFactory factory);

    public Logger getRootLogger();

    public abstract Logger exists(String name);

    public abstract void shutdown();

    public Enumeration getCurrentLoggers();

    /**
     * Deprecated. Please use {@link #getCurrentLoggers} instead.
     */
    public Enumeration getCurrentCategories();

    public abstract void fireAddAppenderEvent(Category logger, Appender appender);

    public abstract void resetConfiguration();

}
