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
015package org.apache.hivemind.impl.servicemodel;
016
017import 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 */
025public 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}