de.uka.ipd.sdq.beagle.core

Interface BlackboardStorer<WRITTEN_TYPE extends Serializable>

Type Parameters:

WRITTEN_TYPE - The type of data the BlackboardStorer wants to write to the blackboard.

All Known Implementing Classes:

FinalJudge, MeasurementResultAnalyserAverage, PcmRepositoryBlackboardFactoryAdder

public interface BlackboardStorer<WRITTEN_TYPE extends Serializable>

Interface for classes that wish to write their state to the Blackboard. The type of the state object is defined by WRITTEN_TYPE.

To illustrate the usage of this interface, two examples follow. We look at a typical use case: Two ResultAnalysers, MyAnalyser and YourAnalyser. Both want to store data on the Blackboard to keep track of whether there is something new to look at.

YourAnalyser simply wants to keep track of the SEFFLoops he has already seen. He wants to use an HashSet to do so:

 

 public class YourAnalyser implements ResultAnalyser, BlackboardStorer<HashSet<SeffLoop>> {

        public boolean canContribute(ReadOnlyBlackboardView blackboard) {
                Set<SeffLoop> alreadySeen = blackboard.readFor(YourAnalyser.class);
                Set<SeffLoop> allLoops = blackboard.getAllSEFFLoops();
                return allLoops.size() > 0 && (alreadySeen == null || !alreadySeen.containsAll(allLoops));
        }

        public boolean contribute(AnalyserBlackboardView blackboard) {
                Set<SeffLoop> alreadySeen = blackboard.readFor(YourAnalyser.class);
                if (alreadySeen == null) {
                        alreadySeen = new HashSet<SeffLoop>();
                        blackboard.writeFor(YourAnalyser.class, alreadySeen);
                }
                Set<SeffLoop> allLoops = blackboard.getAllSEFFLoops();
                Set<SeffLoop> todo = allLoops.removeAll(alreadySeen);

                for (SeffLoop loop : todo) {
                        // do the logic here
                        alreadySeen.add(loop);
                }
        }
 }

 

 

MyAnalyser however, wants to use its own data structure:

 
 public MyAnalyserDataStructure implements Serializable {
                // a whole bunch of getters and setters
 }
 

 

 
 public class MyAnalyser implements ResultAnalyser, BlackboardStorer<MyAnalyserDataStructure> {
  // everything here is like above:
  public boolean canContribute(ReadOnlyBlackboardView blackboard) {
     MyAnalyserDataStructure stored = blackboard.readFor(MyAnalyser.class);
      // …
  }

  public boolean contribute(AnalyserBlackboardView blackboard) {
      MyAnalyserDataStructure stored = blackboard.readFor(MyAnalyser.class);
      // …
      MyAnalyserDataStructure newData = new MyAnalyserDataStructure();
      // …
      blackboard.writeFor(MyAnalyser.class, newData);
      // …
  }
 

 

See Also:

Blackboard