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

1 /*
3    Derby - Class
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
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.
20  */

22 package;
24 import java.util.Properties JavaDoc;
26 /**
27     Allows a module to check its environment
28     before it is selected as an implementation.
29 */

31 public interface ModuleSupportable {
33     /**
34         See if this implementation can support any attributes that are listed in properties.
35         This call may be made on a newly created instance before the
36         boot() method has been called, or after the boot method has
37         been called for a running module.
38         <P>
39         The module can check for attributes in the properties to
40         see if it can fulfill the required behaviour. E.g. the raw
41         store may define an attribute called RawStore.Recoverable.
42         If a temporary raw store is required the property RawStore.recoverable=false
43         would be added to the properties before calling bootServiceModule. If a
44         raw store cannot support this attribute its canSupport method would
45         return null. Also see the Monitor class's prologue to see how the
46         identifier is used in looking up properties.
47         <BR><B>Actually a better way maybe to have properties of the form
48         RawStore.Attributes.mandatory=recoverable,smallfootprint and
49         RawStore.Attributes.requested=oltp,fast
50         </B>
52         @return true if this instance can be used, false otherwise.
53     */

54     public boolean canSupport(Properties JavaDoc properties);
56 }
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