bundles/org.simantics.diagram/src/org/simantics/diagram/connection/ModelledConnectionAdvisor.java

   1 /*******************************************************************************
   2  * Copyright (c) 2007, 2010 Association for Decentralized Information Management
   3  * in Industry THTH ry.
   4  * All rights reserved. This program and the accompanying materials
   5  * are made available under the terms of the Eclipse Public License v1.0
   6  * which accompanies this distribution, and is available at
   7  * http://www.eclipse.org/legal/epl-v10.html
   8  *
   9  * Contributors:
  10  *     VTT Technical Research Centre of Finland - initial API and implementation
  11  *******************************************************************************/
  12 package org.simantics.diagram.connection;
  13
  14 import java.util.ArrayList;
  15 import java.util.Arrays;
  16
  17 import org.simantics.db.ReadGraph;
  18 import org.simantics.db.RequestProcessor;
  19 import org.simantics.db.Resource;
  20 import org.simantics.db.Session;
  21 import org.simantics.db.exception.DatabaseException;
  22 import org.simantics.db.request.Read;
  23 import org.simantics.diagram.content.ConnectionUtil;
  24 import org.simantics.g2d.connection.IConnectionAdvisor;
  25 import org.simantics.g2d.diagram.handler.Topology.Terminal;
  26 import org.simantics.g2d.element.ElementUtils;
  27 import org.simantics.g2d.element.IElement;
  28 import org.simantics.g2d.elementclass.FlagHandler;
  29 import org.simantics.structural2.modelingRules.CPIgnore;
  30 import org.simantics.structural2.modelingRules.ConnectionJudgement;
  31 import org.simantics.structural2.modelingRules.ConnectionJudgementType;
  32 import org.simantics.structural2.modelingRules.IConnectionPoint;
  33 import org.simantics.structural2.modelingRules.IModelingRules;
  34
  35 /**
  36  * To customize, prefer overriding
  37  * {@link #canBeConnected(ReadGraph, IElement, Terminal, IElement, Terminal)}
  38  * and {@link #canBeginConnection(ReadGraph, IElement, Terminal)}.
  39  *
  40  * @author Hannu Niemist&ouml;
  41  */
  42 public class ModelledConnectionAdvisor implements IConnectionAdvisor {
  43
  44     protected IModelingRules modelingRules;
  45     protected Session        session;
  46
  47     /**
  48      * @param modelingRules
  49      * @param session
  50      */
  51     public ModelledConnectionAdvisor(IModelingRules modelingRules,
  52             Session session) {
  53         this.modelingRules = modelingRules;
  54         this.session = session;
  55     }
  56
  57     protected IConnectionPoint getConnectionPoint(ReadGraph g, IElement element, Terminal term) throws DatabaseException {
  58         return getConnectionPoint(g, element, term, false);
  59     }
  60
  61     protected IConnectionPoint getConnectionPoint(ReadGraph g, IElement element, Terminal term, boolean ignoreUnrecognized) throws DatabaseException {
  62         Object obj = null;
  63         if (element != null)
  64             obj = ElementUtils.getObject(element);
  65
  66         if (obj instanceof Resource) {
  67             Resource elementResource = (Resource) obj;
  68             return ConnectionUtil.toConnectionPoint(g, elementResource, term);
  69         }
  70
  71         // FIXME: this currently allows connections to begin from flags
  72         // but is rather hackish.
  73         if (element.getElementClass().containsClass(FlagHandler.class)) {
  74             return CPIgnore.NULL_INSTANCE;
  75         }
  76
  77         if (ignoreUnrecognized)
  78             return CPIgnore.NULL_INSTANCE;
  79
  80         throw new IllegalArgumentException("Cannot get IConnectionPoint for (element,terminal) pair:\n\t" + element + "\n\t" + term);
  81     }
  82
  83     @Override
  84     public Object canBeConnected(Object backend,
  85             final IElement element1, final Terminal term1,
  86             final IElement element2, final Terminal term2) {
  87         try {
  88             if (backend == null)
  89                 backend = session;
  90             return ((RequestProcessor)backend).syncRequest(new Read<Object>() {
  91                 @Override
  92                 public Object perform(ReadGraph g) throws DatabaseException {
  93                     return canBeConnected(g, element1, term1, element2, term2);
  94                 }
  95             });
  96         } catch(DatabaseException e) {
  97             e.printStackTrace();
  98             return null;
  99         }
 100     }
 101
 102     @Override
 103     public boolean canBeginConnection(Object backend,
 104             final IElement element, final Terminal term) {
 105         try {
 106             if (backend == null)
 107                 backend = session;
 108             return ((RequestProcessor)backend).syncRequest(new Read<Boolean>() {
 109                 @Override
 110                 public Boolean perform(ReadGraph g) throws DatabaseException {
 111                     return canBeginConnection(g, element, term);
 112                 }
 113             });
 114         } catch (DatabaseException e) {
 115             e.printStackTrace();
 116             return false;
 117         }
 118     }
 119
 120     protected Object canBeConnected(ReadGraph graph,
 121             IElement element1, Terminal term1,
 122             IElement element2, Terminal term2) throws DatabaseException {
 123         ArrayList<IConnectionPoint> cps = new ArrayList<IConnectionPoint>(2);
 124         if (element1 != null)
 125             cps.add(getConnectionPoint(graph, element1, term1, true));
 126         if (element2 != null)
 127             cps.add(getConnectionPoint(graph, element2, term2, true));
 128
 129         ConnectionJudgement judgement = modelingRules.judgeConnection(graph, cps);
 130         if (judgement.type == ConnectionJudgementType.LEGAL
 131                 // #6751, Apros #12404: a connection should not be automatically
 132                 // denied just because it is not perfectly legal. Further legality
 133                 // should be decided on the client side even though the IConnectionAdvisor
 134                 // interface is not documented to return ConnectionJudgement instances,
 135                 // because the interface knows nothing about this class.
 136                 || judgement.type == ConnectionJudgementType.CANBEMADELEGAL)
 137             return judgement;
 138         return null;
 139     }
 140
 141     protected boolean canBeginConnection(ReadGraph graph,
 142             IElement element, Terminal term) throws DatabaseException {
 143         return modelingRules.judgeConnection(graph,
 144                 Arrays.asList(getConnectionPoint(graph, element, term)))
 145                 .type != ConnectionJudgementType.ILLEGAL;
 146     }
 147
 148 }