src/java/org/apache/log4j/spi/RepositorySelector.java

/*
 * Copyright 1999,2004 The Apache Software Foundation.
 * 
 * Licensed 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;


/**
 * The <code>LogManager</code> uses one (and only one) 
 * <code>RepositorySelector</code> implementation to select the 
 * {@link LoggerRepository} for a particular application context.
 * 
 * <p>It is the responsability of the <code>RepositorySelector</code> 
 * implementation to track the application context. Log4j makes no assumptions 
 * about the application context or on its management.
 * 
 * <p>See also {@link org.apache.log4j.LogManager LogManager}.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @since 1.2
 * */
public interface RepositorySelector {

  /**
   * Get a {@link LoggerRepository} by name. If the named repository does not 
   * exists or is unknown to this selector, then <code>null</code> is returned.
   *
   * @since 1.3
  */
  public LoggerRepository getLoggerRepository(String name);
  
  /**
   * Returns a {@link LoggerRepository} depending on the context. Implementors 
   * must make sure that under all circumstances a valid (non-null) 
   * LoggerRepository is returned.
  */
  public LoggerRepository getLoggerRepository();
  
  /**
   * Remove the repository with the given name from the list maintained by the 
   * respository selector.
   * 
   * <p>When applications are stopped or recycled, this method should be called 
   * to ensure that the associated repository is recycled as well. After the 
   * repository is detached from this selector, the returned value, i.e. the 
   * detached repository, can be used to shutdown the repository.
   * 
   * <p>If more than one application share the same logging context, then the
   * applications need to coordinate their actions.  
   * 
   * @return The LoggerRepository instance that was detached.
   * @since 1.3
   */
  public LoggerRepository detachRepository(String name);
}