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Java > Open Source Codes > org > apache > hivemind > impl > ConstructableServicePoint


1 // Copyright 2004, 2005 The Apache Software Foundation
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 // http://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14
15 package org.apache.hivemind.impl;
16
17 import java.util.List JavaDoc;
18
19 import org.apache.hivemind.definition.ImplementationConstructor;
20 import org.apache.hivemind.definition.ImplementationDefinition;
21 import org.apache.hivemind.events.RegistryShutdownListener;
22 import org.apache.hivemind.internal.ServicePoint;
23
24 /**
25  * "Private" interface used by a {@link org.apache.hivemind.internal.ServiceModel}s to access non-
26  * information about a {@link org.apache.hivemind.internal.ServicePoint}, such as its instance
27  * builder and interceptors.
28  *
29  * @author Howard Lewis Ship
30  */
31 public interface ConstructableServicePoint extends ServicePoint
32 {
33     /**
34      * Returns the constructor that can create the core service implementation. Returns the service
35      * constructor, if defined, or the default service constructor. The default service constructor
36      * comes from the <service-point> itself; other modules can override this default using an
37      * <implementation> element.
38      */
39     ImplementationConstructor getServiceConstructor();
40
41     ImplementationDefinition getImplementationDefinition();
42     
43     /**
44      * Returns a list of {@link org.apache.hivemind.definition.InterceptorConstructor}s,
45      * ordered according to their dependencies. May return null or an empty list.
46      * <p>
47      * Note that the order is tricky! To keep any error messages while ordering the interceptors
48      * understandable, they are ordered according into runtime execution order. Example: If we want
49      * a logging interceptor to operate before a security-check interceptor, we'll write the
50      * following in the descriptor:
51      *
52      * <pre>
53      * &lt;interceptor service-id=&quot;hivemind.LoggingInterceptor&quot; before=&quot;*&quot;/&gt;
54      * &lt;interceptor service-id=&quot;somepackage.SecurityInterceptor&quot;/&gt;
55      * </pre>
56      *
57      * The <code>before</code> value for the first interceptor contribution will be assigned to
58      * the contribution's
59      * {@link org.apache.hivemind.definition.InterceptorConstructor#getFollowingNames() followingNames}
60      * property, because all other interceptors (including the security interceptor) should have
61      * their behavior follow the logging interceptor.
62      * <p>
63      * To get this behavior, the logging interceptor will delegate to the security interceptor, and
64      * the security interceptor will delegate to the core service implementation.
65      * <p>
66      * The trick is that interceptors are applied in reverse order: we start with core service
67      * implementation, wrap it with the security interceptor, then wrap that with the logging
68      * interceptor ... but that's an issue that applies when building the interceptor stack around
69      * the core service implementation.
70      */
71     List JavaDoc getOrderedInterceptorContributions();
72
73     /**
74      * Invoked by the ServiceModel when constuction information (the builder and interceptors) is no
75      * longer needed.
76      */
77     void clearConstructorInformation();
78
79     /**
80      * Adds a shutdown listener; HiveMind uses two coordinators; the first is the
81      * hivemind.ShutdownCoordinator service, which is the coordinator used for service
82      * implementations. The second coordinator is used by the HiveMind infrastructure directly; this
83      * method adds a listener to that coordinator. Why two? It's about order of operations during
84      * registry shutdown; the hivemind.ShutdownCoordinator service's listeners are all invoked
85      * first, the the internal coordinator, to shutdown proxies and the like. This allows services
86      * to communicate during shutdown.
87      *
88      * @param listener
89      * the listener to be added to the infrastructure's shutdown coordinator
90      * @since 1.1.1
91      */
92
93     void addRegistryShutdownListener(RegistryShutdownListener listener);
94 }
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