bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/StandardSessionManager.java

   1 package org.simantics.db.layer0;\r
   2 \r
   3 import java.util.Collection;\r
   4 import java.util.concurrent.ConcurrentHashMap;\r
   5 \r
   6 import org.simantics.db.ReadGraph;\r
   7 import org.simantics.db.common.request.ParametrizedPrimitiveRead;\r
   8 import org.simantics.db.exception.DatabaseException;\r
   9 import org.simantics.db.layer0.variable.NodeSupport;\r
  10 import org.simantics.db.procedure.Listener;\r
  11 \r
  12 abstract public class StandardSessionManager<Node, Engine extends StandardEngine<Node>> {\r
  13 \r
  14     private ConcurrentHashMap<String, Listener<StandardRealm<Node,Engine>>> realmListeners = new ConcurrentHashMap<>();\r
  15     private ConcurrentHashMap<String, StandardRealm<Node,Engine>> REALMS = new ConcurrentHashMap<String, StandardRealm<Node,Engine>>(); \r
  16     private ConcurrentHashMap<String, NodeSupport<Node>> SUPPORTS = new ConcurrentHashMap<String, NodeSupport<Node>>(); \r
  17 \r
  18     // Accessing Realms should be done over ParametrizedPrimitveRead for the\r
  19     // case if a realm is destroyed and new one is created with the same id than\r
  20     // the previously deleted one for the listeners to get discarded and new\r
  21     // registered\r
  22     private class RealmRequest extends ParametrizedPrimitiveRead<String, StandardRealm<Node, Engine>> {\r
  23 \r
  24         public RealmRequest(String parameter) {\r
  25             super(parameter);\r
  26         }\r
  27 \r
  28         @Override\r
  29         public void register(ReadGraph graph, Listener<StandardRealm<Node, Engine>> procedure) {\r
  30 \r
  31             StandardRealm<Node, Engine> realm = REALMS.get(parameter);\r
  32             if (realm == null) {\r
  33                 try {\r
  34                     realm = createRealmInner(graph, parameter);\r
  35                 } catch (DatabaseException e) {\r
  36                     e.printStackTrace();\r
  37                 }\r
  38             }\r
  39             \r
  40             if(procedure.isDisposed()) {\r
  41                 procedure.execute(realm);\r
  42                 return;\r
  43             }\r
  44             \r
  45             Listener<StandardRealm<Node,Engine>> existing = getOrDisposeListener(parameter);\r
  46             assert(existing == null);\r
  47             realmListeners.put(parameter, procedure);\r
  48             procedure.execute(realm);\r
  49         }\r
  50 \r
  51         private StandardRealm<Node,Engine> createRealmInner(ReadGraph graph, String id) throws DatabaseException {\r
  52             Engine engine = createEngine(graph, id);\r
  53             StandardRealm<Node,Engine> realm = createRealm(engine, id);\r
  54             modifyRealms(id, realm);\r
  55             return realm;\r
  56         }\r
  57     }\r
  58     \r
  59     protected StandardSessionManager() {\r
  60     }\r
  61     \r
  62     private Listener<StandardRealm<Node,Engine>> getOrDisposeListener(String key) {\r
  63         Listener<StandardRealm<Node,Engine>> listener = realmListeners.get(key);\r
  64         if(listener != null) {\r
  65             if(listener.isDisposed()) {\r
  66                 realmListeners.remove(key);\r
  67             } else {\r
  68                 return listener;\r
  69             }\r
  70         }\r
  71         return null;\r
  72     }\r
  73     \r
  74     private void modifyRealms(String key, StandardRealm<Node,Engine> realm) {\r
  75         if(realm != null) {\r
  76             REALMS.put(key, realm);\r
  77         } else {\r
  78             REALMS.remove(key);\r
  79         }\r
  80         Listener<StandardRealm<Node,Engine>> listener = getOrDisposeListener(key);\r
  81         if(listener != null) {\r
  82             listener.execute(realm);\r
  83         }\r
  84     }\r
  85 \r
  86     public NodeSupport<Node> getOrCreateNodeSupport(ReadGraph graph, String id) throws DatabaseException {\r
  87         synchronized(SUPPORTS) {\r
  88                 NodeSupport<Node> result = SUPPORTS.get(id);\r
  89                 if(result == null) {\r
  90                         StandardRealm<Node,Engine> realm = getOrCreateRealm(graph, id);\r
  91                         result = new NodeSupport<Node>(realm.getNodeManager());\r
  92                         SUPPORTS.put(id, result);\r
  93                 }\r
  94                 return result;\r
  95         }\r
  96     }\r
  97     \r
  98     public StandardRealm<Node,Engine> getOrCreateRealm(ReadGraph graph, String id) throws DatabaseException {\r
  99         synchronized(REALMS) {\r
 100             return graph.syncRequest(new RealmRequest(id));\r
 101         }\r
 102     }\r
 103     \r
 104     protected abstract Engine createEngine(ReadGraph graph, String id) throws DatabaseException;\r
 105     protected abstract StandardRealm<Node,Engine> createRealm(Engine engine, String id);\r
 106     \r
 107     public void removeRealm(String id) {\r
 108         modifyRealms(id, null);\r
 109         // if node support has been created remove it as well\r
 110         SUPPORTS.remove(id);\r
 111     }\r
 112     \r
 113     public Collection<String> getRealms() {\r
 114         return REALMS.keySet();\r
 115     }\r
 116 }\r