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;
016    
017    import java.util.List;
018    
019    import org.apache.hivemind.definition.ImplementationConstructor;
020    import org.apache.hivemind.definition.ImplementationDefinition;
021    import org.apache.hivemind.events.RegistryShutdownListener;
022    import org.apache.hivemind.internal.ServicePoint;
023    
024    /**
025     * "Private" interface used by a {@link org.apache.hivemind.internal.ServiceModel}s to access non-
026     * information about a {@link org.apache.hivemind.internal.ServicePoint}, such as its instance
027     * builder and interceptors.
028     * 
029     * @author Howard Lewis Ship
030     */
031    public interface ConstructableServicePoint extends ServicePoint
032    {
033        /**
034         * Returns the constructor that can create the core service implementation. Returns the service
035         * constructor, if defined, or the default service constructor. The default service constructor
036         * comes from the <service-point> itself; other modules can override this default using an
037         * <implementation> element.
038         */
039        ImplementationConstructor getServiceConstructor();
040    
041        ImplementationDefinition getImplementationDefinition();
042        
043        /**
044         * Returns a list of {@link org.apache.hivemind.definition.InterceptorConstructor}s,
045         * ordered according to their dependencies. May return null or an empty list.
046         * <p>
047         * Note that the order is tricky! To keep any error messages while ordering the interceptors
048         * understandable, they are ordered according into runtime execution order. Example: If we want
049         * a logging interceptor to operate before a security-check interceptor, we'll write the
050         * following in the descriptor:
051         * 
052         * <pre>
053         *               &lt;interceptor service-id=&quot;hivemind.LoggingInterceptor&quot; before=&quot;*&quot;/&gt;
054         *               &lt;interceptor service-id=&quot;somepackage.SecurityInterceptor&quot;/&gt;
055         * </pre>
056         * 
057         * The <code>before</code> value for the first interceptor contribution will be assigned to
058         * the contribution's
059         * {@link org.apache.hivemind.definition.InterceptorConstructor#getFollowingNames() followingNames}
060         * property, because all other interceptors (including the security interceptor) should have
061         * their behavior follow the logging interceptor.
062         * <p>
063         * To get this behavior, the logging interceptor will delegate to the security interceptor, and
064         * the security interceptor will delegate to the core service implementation.
065         * <p>
066         * The trick is that interceptors are applied in reverse order: we start with core service
067         * implementation, wrap it with the security interceptor, then wrap that with the logging
068         * interceptor ... but that's an issue that applies when building the interceptor stack around
069         * the core service implementation.
070         */
071        List getOrderedInterceptorContributions();
072    
073        /**
074         * Invoked by the ServiceModel when constuction information (the builder and interceptors) is no
075         * longer needed.
076         */
077        void clearConstructorInformation();
078    
079        /**
080         * Adds a shutdown listener; HiveMind uses two coordinators; the first is the
081         * hivemind.ShutdownCoordinator service, which is the coordinator used for service
082         * implementations. The second coordinator is used by the HiveMind infrastructure directly; this
083         * method adds a listener to that coordinator. Why two? It's about order of operations during
084         * registry shutdown; the hivemind.ShutdownCoordinator service's listeners are all invoked
085         * first, the the internal coordinator, to shutdown proxies and the like. This allows services
086         * to communicate during shutdown.
087         * 
088         * @param listener
089         *            the listener to be added to the infrastructure's shutdown coordinator
090         * @since 1.1.1
091         */
092    
093        void addRegistryShutdownListener(RegistryShutdownListener listener);
094    }