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 */
017package org.apache.xbean.naming.global;
018
019import org.apache.xbean.naming.context.ContextFlyweight;
020
021import javax.naming.Context;
022import javax.naming.Name;
023import javax.naming.OperationNotSupportedException;
024import javax.naming.NoInitialContextException;
025import javax.naming.spi.InitialContextFactory;
026import javax.naming.spi.ObjectFactory;
027import java.util.Hashtable;
028
029/**
030 * The GlobalContextManager contains the static global context object.  JNDI effectively requires a single global static
031 * to resolve the root context, and this class manages that static.  This class is also an URLContextFactory and
032 * an InitialContextFactory which returns the registered global context.
033 *
034 * To use this factory simply set the following system property or pass the property in the environment to new InitialContext:
035 *
036 * java.naming.factory.initial = org.apache.xbean.naming.global.GlobalContextManager
037 *
038 * @version $Rev$ $Date$
039 */
040public class GlobalContextManager implements ObjectFactory, InitialContextFactory {
041    private static Context DEFAULT_CONTEXT = new DefaultGlobalContext();
042    private static Context globalContext;
043
044    /**
045     * Gets the global context.  This context is the root of all contexts and will contain entries such as "java:comp".
046     * @return the global context
047     */
048    public static synchronized Context getGlobalContext() {
049        if (globalContext == null) return DEFAULT_CONTEXT;
050        return globalContext;
051    }
052
053    /**
054     * Sets the global context. To invoke this method the calling code must have "setFactory" RuntimePermission.
055     * @param globalContext the new global context
056     */
057    public static synchronized void setGlobalContext(Context globalContext) {
058        SecurityManager security = System.getSecurityManager();
059        if (security != null) {
060            security.checkSetFactory();
061        }
062        GlobalContextManager.globalContext = globalContext;
063    }
064
065    /**
066     * Returns the Context registered with the GlobalManager. This method is equivalent to:
067     *
068     * return GlobalContextManager.getGlobalContext();
069     *
070     * @param obj must be null
071     * @param name ignored
072     * @param nameCtx ignored
073     * @param environment ignored
074     * @return GlobalManager.getGlobalContext()
075     * @throws javax.naming.OperationNotSupportedException if obj is not null
076     */
077    public Object getObjectInstance(Object obj, Name name, Context nameCtx, Hashtable environment) throws Exception {
078        if (obj == null) {
079            return GlobalContextManager.getGlobalContext();
080        } else {
081            throw new OperationNotSupportedException();
082        }
083    }
084
085
086    /**
087     * Returns the Context registered with the GlobalManager. This method is equivalent to:
088     *
089     * return GlobalContextManager.getGlobalContext();
090     *
091     * @param environment ignored
092     * @return GlobalContextManager.getGlobalContext()
093     */
094    public Context getInitialContext(Hashtable environment) {
095        return GlobalContextManager.getGlobalContext();
096    }
097
098    private static class DefaultGlobalContext extends ContextFlyweight {
099        protected Context getContext() throws NoInitialContextException {
100            synchronized (GlobalContextManager.class) {
101                if (globalContext == null) throw new NoInitialContextException("Global context has not been set");
102                return globalContext;
103            }
104        }
105    }
106}