/*

  * Copyright 2006-2011 The Kuali Foundation

  *

  * Licensed under the Educational Community 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.opensource.org/licenses/ecl2.php

  *

  * 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.kuali.rice.core.api.config.property;

 import java.util.Collections;

 import java.util.Map;

 import java.util.Set;

 import java.util.concurrent.ConcurrentHashMap;

 /**

  * Singleton that holds references to global engine objects.

  *

  *

  * @author Kuali Rice Team (rice.collab@kuali.org)

  */

 public class ConfigContext {

     private static final ConcurrentHashMap<ClassLoader, Config> CONFIGS = new ConcurrentHashMap<ClassLoader, Config>();

     private ConfigContext() {

         // nothing to do here

     }

     /**

      * Perform a one-time initialization of the Config system.  This should only be performed by the applicable LifeCycle

      * implementation.

      * @param rootCfg the root config

      */

     public static void init(Config rootCfg) {

             init(Thread.currentThread().getContextClassLoader(), rootCfg);

     }

     /**

      * Initializes the ConfigContext with the given Config and binds it to the given ClassLoader.

      */

     public static void init(ClassLoader classLoader, Config config) {

             CONFIGS.put(classLoader, config);

     }

     public static boolean isInitialized() {

             return !CONFIGS.isEmpty();

     }

     /**

      * Destroy method (mostly to aid testing, as core needs to be torn down appropriately).

      */

     public static void destroy() {

         CONFIGS.clear();

     }

     /**

      * Utility method that all code should call to obtain its appropriate Config object.

      * The Config object which is associated with the caller's context classloader will be

      * returned, being created first if it does not yet exist.

      * @return the Config object which is associated with the caller's context classloader

      */

     public static Config getCurrentContextConfig() {

             return getConfig(Thread.currentThread().getContextClassLoader());

     }

     /**

      * Returns the Config which is bound to the given class loader.  If no configuration is bound to the given class

      * loader this method will return null;

      *

      * @param cl the classloader whose Config to return

      * @return the Config of a particular class loader, or null if no config is bound to the given class loader

      */

     public static Config getConfig(ClassLoader cl) {

         return CONFIGS.get(cl);

     }

     /**

      * @return an immutable view of the Configs entry set

      */

     public static Set<Map.Entry<ClassLoader, Config>> getConfigs() {

         return Collections.unmodifiableSet(CONFIGS.entrySet());

     }

     /**

      * Overrides any existing Config for the classloader

      * @param cl the classloader whose Config should be overridden

      * @param config the config

      */

     public static void overrideConfig(ClassLoader cl, Config config) {

         CONFIGS.put(cl, config);

     }

 }