1 /*******************************************************************************
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2 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
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3 * in Industry THTH ry.
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4 * All rights reserved. This program and the accompanying materials
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5 * are made available under the terms of the Eclipse Public License v1.0
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6 * which accompanies this distribution, and is available at
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7 * http://www.eclipse.org/legal/epl-v10.html
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10 * VTT Technical Research Centre of Finland - initial API and implementation
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11 *******************************************************************************/
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12 package org.simantics.db.common.request;
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14 import org.simantics.db.ReadGraph;
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15 import org.simantics.db.Resource;
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16 import org.simantics.db.exception.DatabaseException;
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17 import org.simantics.db.request.ReadExt;
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18 import org.simantics.db.service.QueryControl;
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20 abstract public class TransientResourceRead<R> extends BinaryRead<Object,Resource,R> implements ReadExt {
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22 protected static final Object WITH_PARENT = new Object();
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24 public TransientResourceRead(ReadGraph graph, Resource parameter) throws DatabaseException {
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25 this(graph, graph.getService(QueryControl.class), parameter);
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28 public TransientResourceRead(ReadGraph graph, QueryControl qc, Resource parameter) throws DatabaseException {
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29 super(resolveFirstParameter(graph, qc), parameter);
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32 final private static Object resolveFirstParameter(ReadGraph graph, QueryControl qc) throws DatabaseException {
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33 if(qc.hasParentRequest(graph)) return WITH_PARENT;
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34 else return graph.getModificationCounter();
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38 final public R perform(ReadGraph _graph) throws DatabaseException {
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39 if(parameter == WITH_PARENT) {
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40 return perform(_graph, parameter2);
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42 QueryControl qc = _graph.getService(QueryControl.class);
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43 ReadGraph graph = qc.getIndependentGraph(_graph);
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44 return perform(graph, parameter2);
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48 abstract public R perform(ReadGraph graph, Resource parameter) throws DatabaseException;
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51 public boolean isImmutable(ReadGraph graph) throws DatabaseException {
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52 return graph.isImmutable(parameter2);
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