001    // Copyright 2004, 2005 The Apache Software Foundation
002    //
003    // Licensed under the Apache License, Version 2.0 (the "License");
004    // you may not use this file except in compliance with the License.
005    // You may obtain a copy of the License at
006    //
007    //     http://www.apache.org/licenses/LICENSE-2.0
008    //
009    // Unless required by applicable law or agreed to in writing, software
010    // distributed under the License is distributed on an "AS IS" BASIS,
011    // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012    // See the License for the specific language governing permissions and
013    // limitations under the License.
014    
015    package org.apache.hivemind.impl.servicemodel;
016    
017    import org.apache.hivemind.impl.ConstructableServicePoint;
018    
019    /**
020     * Implementation of {@link org.apache.hivemind.internal.ServiceModel} for the primitive services
021     * (that do not include the standard deferred instantiation proxy).
022     * 
023     * @author Howard Lewis Ship
024     */
025    public final class PrimitiveServiceModel extends AbstractServiceModelImpl
026    {
027        private Object _constructedService;
028    
029        public PrimitiveServiceModel(ConstructableServicePoint servicePoint)
030        {
031            super(servicePoint);
032        }
033    
034        /**
035         * Constructs the service (the first time this is invoked) and returns it.
036         */
037        public synchronized Object getService()
038        {
039            if (_constructedService == null)
040            {
041                _constructedService = constructServiceImplementation();
042    
043                registerWithShutdownCoordinator(_constructedService);
044            }
045    
046            // Note: if the service's declared interface is a class AND
047            // the service has interceptors, then it will not be possible
048            // to cast the result (since the returned interceptor will implement
049            // the synthetic service interface).
050    
051            return _constructedService;
052        }
053    
054        /**
055         * Invokes {@link #getService()} to ensure that the core service implementation has been
056         * instantiated.
057         */
058        public void instantiateService()
059        {
060            getService();
061        }
062    
063    }