001    /*
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements. See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache license, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License. You may obtain a copy of the License at
008     *
009     *      http://www.apache.org/licenses/LICENSE-2.0
010     *
011     * Unless required by applicable law or agreed to in writing, software
012     * distributed under the License is distributed on an "AS IS" BASIS,
013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     * See the license for the specific language governing permissions and
015     * limitations under the license.
016     */
017    package org.apache.log4j.spi;
018    
019    import java.util.Enumeration;
020    
021    import org.apache.log4j.Appender;
022    import org.apache.log4j.Category;
023    import org.apache.log4j.Level;
024    import org.apache.log4j.Logger;
025    
026    /**
027     * A <code>LoggerRepository</code> is used to create and retrieve <code>Loggers</code>.
028     * <p>
029     * The relation between loggers in a repository depends on the repository but typically loggers are arranged in a named
030     * hierarchy.
031     * </p>
032     * <p>
033     * In addition to the creational methods, a <code>LoggerRepository</code> can be queried for existing loggers, can act
034     * as a point of registry for events related to loggers.
035     * </p>
036     *
037     * @since 1.2
038     */
039    public interface LoggerRepository {
040    
041        /**
042         * Add a {@link HierarchyEventListener} event to the repository.
043         *
044         * @param listener The listener
045         */
046        void addHierarchyEventListener(HierarchyEventListener listener);
047    
048        /**
049         * Returns whether this repository is disabled for a given
050         * level. The answer depends on the repository threshold and the
051         * <code>level</code> parameter. See also {@link #setThreshold}
052         * method.
053         *
054         * @param level The level
055         * @return whether this repository is disabled.
056         */
057        boolean isDisabled(int level);
058    
059        /**
060         * Set the repository-wide threshold. All logging requests below the
061         * threshold are immediately dropped. By default, the threshold is
062         * set to <code>Level.ALL</code> which has the lowest possible rank.
063         *
064         * @param level The level
065         */
066        void setThreshold(Level level);
067    
068        /**
069         * Another form of {@link #setThreshold(Level)} accepting a string
070         * parameter instead of a <code>Level</code>.
071         *
072         * @param val The threshold value
073         */
074        void setThreshold(String val);
075    
076        void emitNoAppenderWarning(Category cat);
077    
078        /**
079         * Get the repository-wide threshold. See {@link #setThreshold(Level)} for an explanation.
080         *
081         * @return the level.
082         */
083        Level getThreshold();
084    
085        Logger getLogger(String name);
086    
087        Logger getLogger(String name, LoggerFactory factory);
088    
089        Logger getRootLogger();
090    
091        Logger exists(String name);
092    
093        void shutdown();
094    
095        @SuppressWarnings("rawtypes")
096        Enumeration getCurrentLoggers();
097    
098        /**
099         * Deprecated. Please use {@link #getCurrentLoggers} instead.
100         *
101         * @return an enumeration of loggers.
102         */
103        @SuppressWarnings("rawtypes")
104        Enumeration getCurrentCategories();
105    
106        void fireAddAppenderEvent(Category logger, Appender appender);
107    
108        void resetConfiguration();
109    }