bundles/org.simantics.db.common/src/org/simantics/db/common/request/ResourceSetGraph.java

   1 package org.simantics.db.common.request;
   2
   3 import gnu.trove.map.hash.THashMap;
   4
   5 import java.util.ArrayList;
   6 import java.util.Collections;
   7 import java.util.List;
   8 import java.util.Map;
   9 import java.util.Set;
  10
  11 import org.simantics.db.ReadGraph;
  12 import org.simantics.db.Resource;
  13 import org.simantics.db.ResourceSet;
  14 import org.simantics.db.exception.DatabaseException;
  15 import org.simantics.db.service.CollectionSupport;
  16
  17 public class ResourceSetGraph {
  18
  19         final public CollectionSupport coll;
  20         final public List<ResourceSetGraph> references;
  21         final public Resource resource;
  22         final public Map<ResourceSet,Set<Resource>> cache = new THashMap<ResourceSet,Set<Resource>>();
  23
  24         public ResourceSetGraph(ReadGraph graph, Resource result) {
  25                 this.resource = result;
  26                 this.references = new ArrayList<ResourceSetGraph>();
  27                 this.coll = graph.getService(CollectionSupport.class);
  28         }
  29
  30         private Set<Resource> probe(ReadGraph graph, ResourceSet types) {
  31             return cache.get(types);
  32         }
  33
  34         private Set<Resource> resolve(ReadGraph graph, ResourceSet types, Set<Resource> visited) throws DatabaseException {
  35
  36             if(visited != null)
  37                 if(!visited.add(this.resource)) return Collections.emptySet();
  38
  39             Set<Resource> cached = cache.get(types);
  40             if(cached != null) return cached;
  41
  42                 boolean includeThis = !types.disjoint(graph.getTypes(this.resource));
  43
  44                 Set<Resource> allRefs = null;
  45                 for(ResourceSetGraph ref : references) {
  46                     Set<Resource> refs = ref.probe(graph, types);
  47                     if(refs == null) {
  48                         if(visited == null) {
  49                             visited = coll.createSet();
  50                             visited.add(this.resource);
  51                         }
  52                         refs = ref.resolve(graph, types, visited);
  53                     }
  54                     if(!refs.isEmpty()) {
  55                         if(allRefs == null) allRefs = coll.createSet(refs.size());
  56                         allRefs.addAll(refs);
  57                     }
  58                 }
  59
  60                 Set<Resource> result = Collections.emptySet();
  61                 if(allRefs != null) {
  62                     if(allRefs.size() == 1) {
  63                         if(includeThis) {
  64                             allRefs.add(resource);
  65                             if(allRefs.size() == 1) result =  Collections.singleton(allRefs.iterator().next());
  66                             else result = allRefs;
  67                         } else {
  68                            result = Collections.singleton(allRefs.iterator().next());
  69                         }
  70                     } else {
  71                 if(includeThis) allRefs.add(resource);
  72                 result = allRefs;
  73                     }
  74                 } else {
  75                     if(includeThis) result = Collections.singleton(resource);
  76                 }
  77
  78                 cache.put(types, result);
  79
  80                 return result;
  81
  82         }
  83
  84         public Set<Resource> resolve(ReadGraph graph, ResourceSet types) throws DatabaseException {
  85                 Set<Resource> result = resolve(graph, types, null);
  86                 if(result == null) result = Collections.emptySet();
  87                 return result;
  88         }
  89
  90 }