ChainFactory


1   // Copyright 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.lib.chain;
16  
17  import java.util.ArrayList  ;
18  import java.util.Iterator  ;
19  import java.util.List  ;
20  import java.util.Map  ;
21  
22  import org.apache.hivemind.ServiceImplementationFactory;
23  import org.apache.hivemind.ServiceImplementationFactoryParameters;
24  import org.apache.hivemind.order.Orderer;
25  
26  /**
27   * Builds a service implementation using {@link org.apache.hivemind.lib.chain.ChainBuilder}.
28   * 
29   * @author Howard M. Lewis Ship
30   * @since 1.1
31   */
32  public class ChainFactory implements ServiceImplementationFactory
33  {
34      private ChainBuilder _chainBuilder;
35  
36      public Object   createCoreServiceImplementation(
37              ServiceImplementationFactoryParameters factoryParameters)
38      {
39          Map   contributions = (Map  ) factoryParameters.getFirstParameter();
40  
41          Orderer orderer = new Orderer(factoryParameters.getErrorLog(), "command");
42  
43          Iterator   i = contributions.values().iterator();
44          while (i.hasNext())
45          {
46              ChainContribution cc = (ChainContribution) i.next();
47              orderer.add(cc, cc.getId(), cc.getAfter(), cc.getBefore());
48          }
49  
50          List   ordered = orderer.getOrderedObjects();
51  
52          List   commands = new ArrayList  (ordered.size());
53  
54          i = ordered.iterator();
55          while (i.hasNext())
56          {
57              ChainContribution cc = (ChainContribution) i.next();
58  
59              // TODO: Validate that command for each ChainContribution implements the
60              // service interface.
61  
62              commands.add(cc.getCommand());
63          }
64  
65          String   toString = "<ChainImplementation for " + factoryParameters.getServiceId() + "("
66                  + factoryParameters.getServiceInterface().getName() + ")>";
67  
68          return _chainBuilder.buildImplementation(
69                  factoryParameters.getServiceInterface(),
70                  commands,
71                  toString);
72      }
73  
74      public void setChainBuilder(ChainBuilder chainBuilder)
75      {
76          _chainBuilder = chainBuilder;
77      }
78  }
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