--- /dev/null
+/*******************************************************************************\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