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Java > Open Source Codes > org > apache > derby > iapi > services > monitor > ModuleControl


1 /*
2
3    Derby - Class org.apache.derby.iapi.services.monitor.ModuleControl
4
5    Licensed to the Apache Software Foundation (ASF) under one or more
6    contributor license agreements. See the NOTICE file distributed with
7    this work for additional information regarding copyright ownership.
8    The ASF licenses this file to you under the Apache License, Version 2.0
9    (the "License"); you may not use this file except in compliance with
10    the License. You may obtain a copy of the License at
11
12       http://www.apache.org/licenses/LICENSE-2.0
13
14    Unless required by applicable law or agreed to in writing, software
15    distributed under the License is distributed on an "AS IS" BASIS,
16    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17    See the License for the specific language governing permissions and
18    limitations under the License.
19
20  */
21
22 package org.apache.derby.iapi.services.monitor;
23
24 import java.util.Properties JavaDoc;
25 import org.apache.derby.iapi.error.StandardException;
26
27 /**
28     ModuleControl is <B>optionally</B> implemented by a module's factory class.
29 */
30
31 public interface ModuleControl {
32
33     /**
34         Boot this module with the given properties. Creates a module instance
35         that can be found using the findModule() methods of Monitor.
36         The module can only be found using one of these findModule() methods
37         once this method has returned.
38         <P>
39         An implementation's boot method can throw StandardException. If it
40         is thrown the module is not registered by the monitor and therefore cannot
41         be found through a findModule(). In this case the module's stop() method
42         is not called, thus throwing this exception must free up any
43         resources.
44         <P>
45         When create is true the contents of the properties object
46         will be written to the service.properties of the persistent
47         service. Thus any code that requires an entry in service.properties
48         must <B>explicitly</B> place the value in this properties set
49         using the put method.
50         <BR>
51         Typically the properties object contains one or more default
52         properties sets, which are not written out to service.properties.
53         These default sets are how callers modify the create process. In a
54         JDBC connection database create the first set of defaults is a properties
55         object that contains the attributes that were set on the jdbc:derby: URL.
56         This attributes properties set has the second default properties set as
57         its default. This set (which could be null) contains the properties
58         that the user set on their DriverManager.getConnection() call, and are thus
59         not owned by cloudscape code, and thus must not be modified by cloudscape
60         code.
61         <P>
62         When create is false the properties object contains all the properties
63         set in the service.properties file plus a <B>limited</B> number of
64         attributes from the JDBC URL attributes or connection properties set.
65         This avoids properties set by the user compromising the boot process.
66         An example of a property passed in from the JDBC world is the bootPassword
67         for encrypted databases.
68
69         <P>
70         Code should not hold onto the passed in properties reference after boot time
71         as its contents may change underneath it. At least after the complete boot
72         is completed, the links to all the default sets will be removed.
73
74         @exception StandardException Module cannot be started.
75
76         @see Monitor
77         @see ModuleFactory
78         
79     */
80
81     public void boot(boolean create, Properties JavaDoc properties)
82         throws StandardException;
83
84     /**
85         Stop the module.
86
87         The module may be found via a findModule() method until some time after
88         this method returns. Therefore the factory must be prepared to reject requests
89         to it once it has been stopped. In addition other modules may cache a reference
90         to the module and make requests of it after it has been stopped, these requests
91         should be rejected as well.
92
93         @see Monitor
94         @see ModuleFactory
95     */
96
97     public void stop();
98
99
100 }
101
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