+/*******************************************************************************\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.common.request;\r
+\r
+import org.simantics.db.ReadGraph;\r
+import org.simantics.db.exception.DatabaseException;\r
+import org.simantics.db.service.QueryControl;\r
+\r
+abstract public class TransientUnaryRead<P, R> extends BinaryRead<Object,P,R> {\r
+\r
+ protected static final Object WITH_PARENT = new Object();\r
+ \r
+ public TransientUnaryRead(ReadGraph graph, P parameter) throws DatabaseException {\r
+ this(graph, graph.getService(QueryControl.class), parameter);\r
+ }\r
+ \r
+ public TransientUnaryRead(ReadGraph graph, QueryControl qc, P parameter) throws DatabaseException {\r
+ super(resolveFirstParameter(graph, qc), parameter);\r
+ }\r
+\r
+ final private static Object resolveFirstParameter(ReadGraph graph, QueryControl qc) throws DatabaseException {\r
+ if(qc.hasParentRequest(graph)) return WITH_PARENT;\r
+ else return graph.getModificationCounter();\r
+ }\r
+\r
+ @Override\r
+ final public R perform(ReadGraph _graph) throws DatabaseException {\r
+ if(parameter == WITH_PARENT) {\r
+ return perform(_graph, parameter2);\r
+ } else {\r
+ QueryControl qc = _graph.getService(QueryControl.class);\r
+ ReadGraph graph = qc.getIndependentGraph(_graph);\r
+ return perform(graph, parameter2);\r
+ }\r
+ }\r
+\r
+ abstract public R perform(ReadGraph graph, P parameter) throws DatabaseException;\r
+ \r
+}\r