Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.db.impl / src / org / simantics / db / impl / query / ExternalReadEntry.java

diff --git a/bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/ExternalReadEntry.java b/bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/ExternalReadEntry.java
new file mode 100644 (file)
index 0000000..a411fa7
--- /dev/null
+++ b/bundles/org.simantics.db.impl/src/org/simantics/db/impl/query/ExternalReadEntry.java
@@ -0,0 +1,183 @@
+/*******************************************************************************\r
+ * Copyright (c) 2007, 2010 Association for Decentralized Information Management\r
+ * in Industry THTH ry.\r
+ * All rights reserved. This program and the accompanying materials\r
+ * are made available under the terms of the Eclipse Public License v1.0\r
+ * which accompanies this distribution, and is available at\r
+ * http://www.eclipse.org/legal/epl-v10.html\r
+ *\r
+ * Contributors:\r
+ *     VTT Technical Research Centre of Finland - initial API and implementation\r
+ *******************************************************************************/\r
+package org.simantics.db.impl.query;\r
+\r
+import java.util.ArrayList;\r
+import java.util.LinkedList;\r
+\r
+import org.simantics.db.impl.graph.ReadGraphImpl;\r
+import org.simantics.db.procedure.Procedure;\r
+import org.simantics.db.request.ExternalRead;\r
+import org.simantics.db.request.RequestFlags;\r
+\r
+final public class ExternalReadEntry<T> extends CacheEntryBase {\r
+\r
+    final LinkedList<T> items = new LinkedList<T>();\r
+    \r
+//    public ArrayList<Procedure<T>> procs;\r
+\r
+    protected ExternalRead<T> request;\r
+\r
+    @Override\r
+    int makeHash() {\r
+       return request.hashCode();\r
+    }\r
+    \r
+    @Override\r
+    public Object getOriginalRequest() {\r
+        return request;\r
+    }\r
+    \r
+    @Override\r
+    public void clearResult(QuerySupport support) {\r
+    }\r
+    \r
+    @Override\r
+    public void discard() {\r
+        request.unregistered();\r
+        request = null;\r
+        super.discard();\r
+    }\r
+    \r
+    public ExternalReadEntry(ExternalRead<T> request) {\r
+        assert request != null;\r
+        this.request = request;\r
+    }\r
+    \r
+    final public void queue(T item) {\r
+       synchronized(items) {\r
+               items.addLast(item);\r
+               // TODO: implement flags/logic in ExternalRead to state that all but the latest request result can be evaporated\r
+               // In some cases where data is produced really fast this might be necessary but currently this queueing will do.\r
+       }\r
+    }\r
+    \r
+    final public void addOrSet(QueryProcessor processor, Object item) {\r
+\r
+        try {\r
+        \r
+            assert(isPending());\r
+\r
+            ArrayList<Procedure<T>> p = null;\r
+\r
+            synchronized(this) {\r
+\r
+                setResult(item);\r
+                setReady();\r
+//                p = procs;\r
+//                procs = null;\r
+\r
+            }\r
+\r
+//            if(p != null)\r
+//                for(Procedure proc : p) {\r
+//                    proc.execute((T)item);\r
+//                }\r
+\r
+        } catch (Throwable t) {\r
+            t.printStackTrace();\r
+        }\r
+        \r
+    }\r
+    \r
+    @Override\r
+    final public Query getQuery() {\r
+       \r
+        return new Query() {\r
+\r
+                       @Override\r
+                       public void recompute(ReadGraphImpl graph, Object provider, CacheEntry entry) {\r
+\r
+                           final QueryProcessor qp = (QueryProcessor)provider;\r
+                           synchronized(items) {\r
+\r
+                               if(entry.isExcepted()) {\r
+                                       \r
+                                       // Exception persists\r
+                                       \r
+                               } else {\r
+                               \r
+                                       // Update\r
+                                       if(!items.isEmpty()) {\r
+                                               setResult(items.removeFirst());\r
+                                       }\r
+                                       // Reschedule\r
+                                           if(!items.isEmpty()) {\r
+                                               qp.updatePrimitive(request);\r
+                                           }\r
+                                           \r
+                                           setReady();\r
+                                           \r
+                               }\r
+                               \r
+                           }\r
+                               \r
+                       }\r
+\r
+                       @Override\r
+                       public void removeEntry(QueryProcessor processor) {\r
+                               processor.externalReadMap.remove(request);\r
+                       }\r
+\r
+                       @Override\r
+                       public int type() {\r
+                               return RequestFlags.IMMEDIATE_UPDATE;\r
+                       }\r
+                       \r
+                       @Override\r
+                       public String toString() {\r
+                               if(request == null) return "DISCARDED ExternalRead";\r
+                               else return request.toString();\r
+                       }\r
+               \r
+        };\r
+        \r
+    }\r
+\r
+       public void performFromCache(Object procedure) {\r
+               \r
+        Procedure<T> proc = (Procedure<T>)procedure;\r
+\r
+           if(isExcepted()) {\r
+            \r
+            proc.exception((Throwable)getResult());\r
+            \r
+        } else {\r
+            \r
+            proc.execute((T)getResult());\r
+\r
+        }\r
+               \r
+       }\r
+\r
+       @Override\r
+       public String toString() {\r
+               if(request == null) return "DISCARDED ExternalRead " + System.identityHashCode(this);\r
+               else return request.toString() + " " + + System.identityHashCode(this);\r
+       }\r
+\r
+    @Override\r
+    public void performFromCache(ReadGraphImpl graph, Object provider, Object procedure) {\r
+        performFromCache(procedure);\r
+    }\r
+    \r
+    @Override\r
+    public void setReady() {\r
+       super.setReady();\r
+    }\r
+    \r
+    @Override\r
+    void prepareRecompute(QuerySupport querySupport) {\r
+       // Do nothing - the state is already set and cannot be recomputed on demand\r
+    }\r
+\r
+}\r