fixed missing oderConstraints

src/main/java/de/dhbwstuttgart/typeinference/unify/ConstraintSetRepository.java

@@ -1,21 +0,0 @@
-package de.dhbwstuttgart.typeinference.unify;
-
-import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
-
-import java.util.HashSet;
-import java.util.Set;
-
-public class ConstraintSetRepository {
-    private Set<Integer> sets = new HashSet<>();
-
-    public boolean containsSet(Set<Set<UnifyPair>> set){
-        Integer hash = Integer.valueOf(set.hashCode());
-
-        if(sets.contains(hash)){
-            return true;
-        }else{
-            sets.add(hash);
-            return false;
-        }
-    }
-}

src/main/java/de/dhbwstuttgart/typeinference/unify/IUnifyResultListener.java

@@ -1,11 +0,0 @@
-package de.dhbwstuttgart.typeinference.unify;
-
-import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
-
-import java.util.Set;
-
-public interface IUnifyResultListener {
-
-	void onNewTypeResultFound(Set<Set<UnifyPair>> evt);
-
-}

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify.java

@@ -3,12 +3,16 @@ package de.dhbwstuttgart.typeinference.unify;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.Writer;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Set;
 import java.util.concurrent.ForkJoinPool;
 
 import de.dhbwstuttgart.typeinference.constraints.Constraint;
+import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
+import de.dhbwstuttgart.typeinference.constraints.Pair;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
+import de.dhbwstuttgart.typeinference.unify.model.FiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 
 public class TypeUnify {
@@ -24,12 +28,9 @@ public class TypeUnify {
 	 * @param cons
 	 * @return
 	 */
-	public Set<Set<UnifyPair>> unify(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModelParallel ret, UnifyTaskModelParallel usedTasks) {
-		ForkJoinPool pool = new ForkJoinPool(Runtime.getRuntime().availableProcessors(), ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true);
-		ConstraintSetRepository constraintSetRepository = new ConstraintSetRepository();
-		usedTasks.setPool(pool);
-		ret.setPool(pool);
-		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, constraintSetRepository);
+	public Set<Set<UnifyPair>> unify(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModel ret, UnifyTaskModel usedTasks) {
+		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, usedTasks);
+		ForkJoinPool pool = new ForkJoinPool();
 		pool.invoke(unifyTask);
 		Set<Set<UnifyPair>> res =  unifyTask.join();
 		try {
@@ -53,12 +54,9 @@ public class TypeUnify {
 	 * @param ret
 	 * @return
 	 */
-	public UnifyResultModelParallel unifyAsync(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModelParallel ret, UnifyTaskModelParallel usedTasks) {
-		ForkJoinPool pool = new ForkJoinPool(Runtime.getRuntime().availableProcessors(), ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true);
-		ConstraintSetRepository constraintSetRepository = new ConstraintSetRepository();
-		usedTasks.setPool(pool);
-		ret.setPool(pool);
-		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, constraintSetRepository);
+	public UnifyResultModel unifyAsync(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModel ret, UnifyTaskModel usedTasks) {
+		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, usedTasks);
+		ForkJoinPool pool = new ForkJoinPool();
 		pool.invoke(unifyTask);
 		return ret;
 	}
@@ -74,12 +72,10 @@ public class TypeUnify {
 	 * @param ret
 	 * @return
 	 */
-	public UnifyResultModelParallel unifyParallel(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModelParallel ret, UnifyTaskModelParallel usedTasks) {
-		ForkJoinPool pool = new ForkJoinPool(Runtime.getRuntime().availableProcessors(), ForkJoinPool.defaultForkJoinWorkerThreadFactory, null, true);
-		ConstraintSetRepository constraintSetRepository = new ConstraintSetRepository();
-		usedTasks.setPool(pool);
-		ret.setPool(pool);
-		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, constraintSetRepository, statistics);
+	public UnifyResultModel unifyParallel(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModel ret, UnifyTaskModel usedTasks) {
+		TypeUnifyTask unifyTask = //new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, usedTasks);
+				new TypeUnifyTask(undConstrains, oderConstraints, fc, true, logFile, log, 0, ret, usedTasks, statistics);
+		ForkJoinPool pool = new ForkJoinPool();
 		pool.invoke(unifyTask);
 		Set<Set<UnifyPair>> res =  unifyTask.join();
 		try {
@@ -112,9 +108,8 @@ public class TypeUnify {
 	 * @param cons
 	 * @return
 	 */
-	public Set<Set<UnifyPair>> unifyOderConstraints(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModelParallel ret, UnifyTaskModelParallel usedTasks) {
-		ConstraintSetRepository constraintSetRepository = new ConstraintSetRepository();
-		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, false, logFile, log, 0, ret, constraintSetRepository);
+	public Set<Set<UnifyPair>> unifyOderConstraints(Set<UnifyPair> undConstrains, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, Writer logFile, Boolean log, UnifyResultModel ret, UnifyTaskModel usedTasks) {
+		TypeUnifyTask unifyTask = new TypeUnifyTask(undConstrains, oderConstraints, fc, false, logFile, log, 0, ret, usedTasks);
 		unifyTask.statistics = statistics;
 		Set<Set<UnifyPair>> res = unifyTask.compute();
 		try {

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnify2Task.java

@@ -15,58 +15,62 @@ import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 
 public class TypeUnify2Task extends TypeUnifyTask {
+       
+       Set<Set<UnifyPair>> setToFlatten;
+       Set<UnifyPair> methodSignatureConstraintUebergabe;
 
-    Set<Set<UnifyPair>> setToFlatten;
-    Set<UnifyPair> methodSignatureConstraintUebergabe;
-
-    //statistics
-    TypeUnify2Task(Set<Set<UnifyPair>> setToFlatten, Set<UnifyPair> eq,
-                   List<Set<Constraint<UnifyPair>>> oderConstraints,
-                   Set<UnifyPair> nextSetElement,
-                   IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModelParallel urm,
-                   Set<UnifyPair> methodSignatureConstraintUebergabe, ConstraintSetRepository constraintSetRepository, Writer statistics) {
-        this(setToFlatten, eq, oderConstraints, nextSetElement, fc, parallel, logFile, log, rekTiefe, urm, methodSignatureConstraintUebergabe, constraintSetRepository);
-
-    }
-
-    public TypeUnify2Task(Set<Set<UnifyPair>> setToFlatten, Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, Set<UnifyPair> nextSetElement, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModelParallel urm, Set<UnifyPair> methodSignatureConstraintUebergabe, ConstraintSetRepository constraintSetRepository) {
-        super(eq, oderConstraints, fc, parallel, logFile, log, rekTiefe, urm, constraintSetRepository);
-        this.setToFlatten = setToFlatten;
-        this.nextSetElement = nextSetElement;
-        this.methodSignatureConstraintUebergabe = methodSignatureConstraintUebergabe;
-    }
-
-    Set<UnifyPair> getNextSetElement() {
-        return nextSetElement;
-    }
-
-    @Override
-    protected Set<Set<UnifyPair>> compute() {
-        if (one) {
-            System.out.println("two");
-        }
-        one = true;
-        Set<Set<UnifyPair>> res = new HashSet<>();
-
-        if (!constraintSetRepository.containsSet(setToFlatten)) {
-            res = unify2(setToFlatten, eq, oderConstraintsField, fc, parallel, rekTiefeField, methodSignatureConstraintUebergabe);
-        }
+       //statistics
+       TypeUnify2Task(Set<Set<UnifyPair>> setToFlatten, Set<UnifyPair> eq, 
+    		   List<Set<Constraint<UnifyPair>>> oderConstraints, 
+    		   Set<UnifyPair> nextSetElement, 
+    		   IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModel urm, UnifyTaskModel usedTasks, 
+    		   Set<UnifyPair> methodSignatureConstraintUebergabe, Writer statistics) {
+    	   this(setToFlatten, eq, oderConstraints, nextSetElement, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, methodSignatureConstraintUebergabe );
+    	   
+       }
+       
+       public TypeUnify2Task(Set<Set<UnifyPair>> setToFlatten, Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, Set<UnifyPair> nextSetElement, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModel urm, UnifyTaskModel usedTasks, Set<UnifyPair> methodSignatureConstraintUebergabe) {
+               super(eq, oderConstraints, fc, parallel, logFile, log, rekTiefe, urm, usedTasks);
+               this.setToFlatten = setToFlatten;
+               this.nextSetElement = nextSetElement;
+               this.methodSignatureConstraintUebergabe = methodSignatureConstraintUebergabe;
+       }
+       
+       Set<UnifyPair> getNextSetElement() {
+    	   return nextSetElement;
+       }
+       
+       @Override
+       protected Set<Set<UnifyPair>> compute() {
+               if (one) {
+                       System.out.println("two");
+               }
+               one = true;
+               Set<Set<UnifyPair>> res = unify2(setToFlatten, eq, oderConstraintsField, fc, parallel, rekTiefeField, methodSignatureConstraintUebergabe);
                /*if (isUndefinedPairSetSet(res)) { 
                        return new HashSet<>(); }
                else
-               */
-        //writeLog("xxx");
-        //noOfThread--;
-        return res;
-    }
+               */ 
+               //writeLog("xxx");
+               //noOfThread--;
+               synchronized (usedTasks) {
+            	   if (this.myIsCancelled()) {
+   						return new HashSet<>();
+   					}
+   					else {
+   						return res;
+   					}
+   				}
+       	}
+       
+       public void closeLogFile() {
 
-    public void closeLogFile() {
-
-        try {
-            logFile.close();
-        } catch (IOException ioE) {
-            System.err.println("no log-File" + thNo);
-        }
-
-    }
+           try {
+				logFile.close();
+			}
+			catch (IOException ioE) {
+				System.err.println("no log-File" + thNo);
+			}
+           
+       }
 }

src/main/java/de/dhbwstuttgart/typeinference/unify/TypeUnifyTask.java

@@ -73,10 +73,12 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 	/**
 	 * Fuer die Threads
 	 */
-	UnifyResultModelParallel urm;
+	UnifyResultModel urm;
+	protected static int noOfThread = 0;
 	private static int totalnoOfThread = 0;
 	int thNo;
 	protected boolean one = false;
+	Integer MaxNoOfThreads = 128;
 
 	public static final String rootDirectory = System.getProperty("user.dir")+"/test/logFiles/";
 	Writer logFile;
@@ -125,8 +127,11 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 	
 	static Integer  noShortendElements = 0;
 	
+	Boolean myIsCanceled = false;
+	
+	volatile UnifyTaskModel usedTasks;
+	
 	static Writer statistics;
-	protected ConstraintSetRepository constraintSetRepository;
 	
 	public TypeUnifyTask() { 
 		rules = new RuleSet();
@@ -147,11 +152,11 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 	*/
 	
 	//statistics
-	public TypeUnifyTask(Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModelParallel urm, ConstraintSetRepository constraintSetRepository, Writer statistics) {
-		this(eq,oderConstraints,  fc,  parallel,  logFile,  log,  rekTiefe,  urm, constraintSetRepository);
+	public TypeUnifyTask(Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModel urm, UnifyTaskModel usedTasks, Writer statistics) {
+		this(eq,oderConstraints,  fc,  parallel,  logFile,  log,  rekTiefe,  urm,  usedTasks);
 		this.statistics = statistics;
 	}
-	public TypeUnifyTask(Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModelParallel urm, ConstraintSetRepository constraintSetRepository) {
+	public TypeUnifyTask(Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, boolean parallel, Writer logFile, Boolean log, int rekTiefe, UnifyResultModel urm, UnifyTaskModel usedTasks) {
 		synchronized (this) {
             if(statistics==null){
                 statistics = new NullWriter();
@@ -174,7 +179,8 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			this.parallel = parallel;
 			this.logFile = logFile;
 			this.log = log;
-
+			
+			noOfThread++; 
 			totalnoOfThread++;
 			//writeLog("thNo1 " + thNo);
 			thNo = totalnoOfThread;
@@ -204,7 +210,8 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			rules = new RuleSet(logFile);
 			this.rekTiefeField = rekTiefe;
 			this.urm = urm;
-			this.constraintSetRepository = constraintSetRepository;
+			this.usedTasks = usedTasks;
+			this.usedTasks.add(this);
 		}
 	}
 	
@@ -240,6 +247,13 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		}		
 }
 */
+	void myCancel(Boolean b) {
+		myIsCanceled = true;
+	}
+	
+	public boolean myIsCancelled() {
+		return myIsCanceled;
+	}
 	
 	protected Set<Set<UnifyPair>> compute() {
 		if (one) {
@@ -255,6 +269,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				.filter(x -> x.size()>1)
 				.collect(Collectors.toCollection(ArrayList::new));
 		Set<Set<UnifyPair>> res = unify(neweq, remainingOderconstraints, fc, parallel, rekTiefeField, new HashSet<>());
+		noOfThread--;
 		try {
 			logFile.close();
 		}
@@ -268,7 +283,14 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 				throw new DebugException("Unresolved constraints: " + res.toString()); //return new HashSet<>();
 			}
 		else {
-			return res;
+			synchronized (usedTasks) {
+				if (this.myIsCancelled()) {
+					return new HashSet<>();
+				}
+				else {
+					return res;
+				}
+			}
 		}
 	}
 /*	
@@ -301,6 +323,12 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 
                 //.collect(Collectors.toCollection(HashSet::new)));
 		
+		synchronized (usedTasks) {
+			if (this.myIsCancelled()) {
+				return new HashSet<>();
+			}
+		}
+		
 		rekTiefe++;
 		nOfUnify++;
         writeLog(nOfUnify.toString() + " Unifikation: " + eq.toString());
@@ -482,6 +510,12 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		//		.collect(Collectors.toCollection(HashSet::new));
 		//Muss auskommentiert werden, wenn computeCartesianRecursive ENDE
 		
+		synchronized (usedTasks) {
+			if (this.myIsCancelled()) {
+				return new HashSet<>();
+			}
+		}
+		
 		Set<Set<UnifyPair>> eqPrimePrimeSet = new HashSet<>();
 		
 		Set<TypeUnifyTask> forks = new HashSet<>();
@@ -655,8 +689,15 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			System.out.print("");
 		}
 		*/
-		Set<Set<UnifyPair>> result = new HashSet<>();
-
+		Set<Set<UnifyPair>> result = new HashSet<>(); 
+		int variance = 0;
+		
+		/* Varianzbestimmung Anfang 
+		 * Oderconstraint, wenn entweder kein Basepair oder unterschiedliche Basepairs => oderConstraint = true;
+		 * Varianz = 1 => Argumentvariable
+		 * Varianz = -1 => Rückgabevariable
+		 * Varianz = 0 => unklar 
+		 * Varianz = 2 => Operatoren oderConstraints */
 		ArrayList<UnifyPair> zeroNextElem = new ArrayList<>(nextSetasList.get(0)); 
 		UnifyPair fstBasePair = zeroNextElem.remove(0).getBasePair();
 		Boolean oderConstraint = false;
@@ -674,6 +715,9 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 						.filter(d -> d.isPresent())
 						.map(e -> e.get())
 						.findAny();
+				if (xi.isPresent()) {
+					variance = xi.get();
+				}
 			}
 			else {
 				oderConstraint = true;
@@ -682,6 +726,29 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		else {
 			oderConstraint = true;
 		}
+		
+		//Varianz-Bestimmung Oder-Constraints 
+		if (oderConstraint) {
+			if (printtag) System.out.println("nextSetasList " + nextSetasList);
+			Optional<Integer> optVariance = 
+					nextSetasList.iterator()
+				 			  	 .next()
+				 			  	 .stream()
+				 			  	 .filter(x -> x.getGroundBasePair().getLhsType() instanceof PlaceholderType && 
+				 			  			! (x.getRhsType() instanceof PlaceholderType) &&
+				 			  			 x.getPairOp() == PairOperator.EQUALSDOT)
+				 			  	 .map(x -> 
+				 			  	 ((PlaceholderType)x.getGroundBasePair().getLhsType()).getVariance())
+				 			  	 .reduce((n,m) ->  { if ((n == 0) && (m==0)) return 0;
+				 			  	 					 else if (n !=0) return n;  //es muss mindestens eine Variance != 0 sein
+				 			  	 					      else return m;
+				 			  	                   });
+			//Fuer Operatorenaufrufe wird variance auf 2 gesetzt.
+			//da kein Receiver existiert also kein x.getGroundBasePair().getLhsType() instanceof PlaceholderType
+			//Bei Varianz = 2 werden alle Elemente des Kartesischen Produkts abgearbeitet
+			variance = optVariance.isPresent() ? optVariance.get() : 2;
+		}
+		/* Varianzbestimmung Ende */
 
 		//writeLog("nextSetasList: " + nextSetasList.toString());
 		Set<UnifyPair> nextSetElem =  nextSetasList.get(0);
@@ -748,7 +815,80 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			
 			writeLog("nextSet: " + nextSet.toString());
 			writeLog("nextSetasList: " + nextSetasList.toString());
-
+			
+			/* staistics Nextvar an Hand Varianzbestimmung auskommentieren Anfang 
+			if (variance == 1) {
+				a = oup.max(nextSetasList.iterator());
+				nextSetasList.remove(a);
+				if (oderConstraint) {
+					nextSetasListOderConstraints.add(((Constraint<UnifyPair>)a).getExtendConstraint());
+				}	
+				writeLog("nextSetasListOderConstraints 1: " + nextSetasListOderConstraints);
+				nextSetasListRest = new ArrayList<>(nextSetasList);
+				Iterator<Set<UnifyPair>> nextSetasListItRest = new ArrayList<Set<UnifyPair>>(nextSetasListRest).iterator();
+				while (nextSetasListItRest.hasNext()) {
+					Set<UnifyPair> a_next = nextSetasListItRest.next();
+					if (//a.equals(a_next) || 
+							(oup.compare(a, a_next) == 1)) {
+						nextSetasListRest.remove(a_next);
+					}
+				}
+				
+				//Alle maximale Elemente in  nextSetasListRest bestimmen
+				//nur für diese wird parallele Berechnung angestossen.
+				nextSetasListRest = oup.maxElements(nextSetasListRest);
+			}
+			else if (variance == -1) {
+				a = oup.min(nextSetasList.iterator());
+				writeLog("Min: a in " + variance + " "+ a);
+				if (oderConstraint) {
+					nextSetasListOderConstraints.add(((Constraint<UnifyPair>)a).getExtendConstraint());
+				}	
+				writeLog("nextSetasListOderConstraints -1: " + nextSetasListOderConstraints);
+				nextSetasList.remove(a);
+				nextSetasListRest = new ArrayList<>(nextSetasList);
+				Iterator<Set<UnifyPair>> nextSetasListItRest = new ArrayList<Set<UnifyPair>>(nextSetasListRest).iterator();
+				while (nextSetasListItRest.hasNext()) {
+					Set<UnifyPair> a_next = nextSetasListItRest.next();
+					if (//a.equals(a_next) || 
+							(oup.compare(a, a_next) == -1)) {
+						nextSetasListRest.remove(a_next);
+					}
+				}
+				//Alle minimalen Elemente in  nextSetasListRest bestimmen
+				//nur für diese wird parallele Berechnung angestossen.
+				nextSetasListRest = oup.minElements(nextSetasListRest);
+			}
+			else if (variance == 2) {
+				a = nextSetasList.remove(0);
+				
+				//Fuer alle Elemente wird parallele Berechnung angestossen.
+				nextSetasListRest = new ArrayList<>(nextSetasList);
+			} 
+			else if (variance == 0) {
+				//wenn a <. theta dann ist ein maximales Element sehr wahrscheinlich
+				//wenn theta <. a dann ist ein minimales Element sehr wahrscheinlich
+				if (!oderConstraint && optOrigPair != null && optOrigPair.isPresent()) {
+					if (optOrigPair.get().getBasePair().getLhsType() instanceof PlaceholderType) {
+						a = oup.max(nextSetasList.iterator());
+					}
+					else {
+						a = oup.min(nextSetasList.iterator());
+					}
+					nextSetasList.remove(a);
+				}
+				else {
+					if (oderConstraint) {
+						a = oup.max(nextSetasList.iterator());
+						nextSetasList.remove(a);
+						nextSetasListOderConstraints.add(((Constraint<UnifyPair>)a).getExtendConstraint());
+					}
+					else {
+						a = nextSetasList.remove(0);
+					}
+				}
+			}
+			Nextvar an Hand Varianzbestimmung auskommentieren Ende */
 			a = nextSetasList.remove(0); //statisticsList
 			
 			//writeStatistics(a.toString());
@@ -759,6 +899,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 
 			i++;
 			Set<Set<UnifyPair>> elems = new HashSet<Set<UnifyPair>>(oneElems);
+			writeLog("a1: " + rekTiefe + "  "+ "variance:  "+ variance + " " + a.toString()+ "\n");
 			
 			//Ergebnisvariable für den aktuelle Thread
 			Set<Set<UnifyPair>> res = new HashSet<>();
@@ -783,50 +924,292 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 			/* Wenn parallel gearbeitet wird, wird je nach Varianz ein neuer Thread
 			 * gestartet, der parallel weiterarbeitet.
 			 */
-			if(parallel){
+			if(parallel && (variance == 1) && noOfThread <= MaxNoOfThreads) {
 				Set<TypeUnify2Task> forks = new HashSet<>();
 				Set<UnifyPair> newEqOrig = new HashSet<>(eq);
 				Set<Set<UnifyPair>> newElemsOrig = new HashSet<>(elems);
 				List<Set<Constraint<UnifyPair>>> newOderConstraintsOrig = new ArrayList<>(oderConstraints);
 				newElemsOrig.add(a);
-				TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, methodSignatureConstraint, constraintSetRepository);
-				//Überprüfen, ob das Set bereits berechnet wurde
-				forkOrig.fork();
-
-				while (!nextSetasList.isEmpty()) {
-					Set<UnifyPair> nSaL = nextSetasList.removeFirst();
-
-					if (oderConstraint) {
-						nextSetasListOderConstraints.add(((Constraint<UnifyPair>) nSaL).getExtendConstraint());
+				
+				/* FORK ANFANG */
+				TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, methodSignatureConstraint);
+				//forks.add(forkOrig);
+				synchronized(usedTasks) {
+					if (this.myIsCancelled()) {
+						return new HashSet<>();
+					}
+					forkOrig.fork();
+				}
+				/* FORK ENDE */
+				
+				synchronized (this) {
+					writeLog("a in " + variance + " "+ a);
+					writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+				}
+				while (!nextSetasList.isEmpty()) {
+					Set<UnifyPair> nSaL = nextSetasList.remove(0);
+					synchronized (this) { //nextSetasList.remove(nSaL);
+						writeLog("1 RM" + nSaL.toString());
+					}
+					
+					if (!oderConstraint) {
+						
+						/* statistics sameEq wird nicht betrachtet ANGFANG
+						//ueberpruefung ob zu a =. ty \in nSaL in sameEqSet ein Widerspruch besteht
+						if (!sameEqSet.isEmpty() && !checkNoContradiction(nSaL, sameEqSet, result)) {
+							nSaL = null;
+							noShortendElements++;
+							continue;
+						}
+						statistics sameEq wird nicht betrachtet ENDE */
+					}
+					else {
+						nextSetasListOderConstraints.add(((Constraint<UnifyPair>)nSaL).getExtendConstraint());
 					}
-
 					Set<UnifyPair> newEq = new HashSet<>(eq);
 					Set<Set<UnifyPair>> newElems = new HashSet<>(elems);
 					List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
 					newElems.add(nSaL);
-					TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, new HashSet<>(methodSignatureConstraint), constraintSetRepository);
+					TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, new HashSet<>(methodSignatureConstraint));
 					forks.add(fork);
-					fork.fork();
-				}
-
-				res = forkOrig.join();
-
-				forks.forEach(x -> writeLog("wait: " + x.thNo));
-				for (TypeUnify2Task fork : forks) {
-					Set<Set<UnifyPair>> fork_res = new HashSet<>();
-					fork_res = fork.join();
-					add_res.add(fork_res);
-					if (!isUndefinedPairSetSet(fork_res)) {
-						aParDef.add(fork.getNextSetElement());
+					synchronized(usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+						fork.fork();
 					}
 				}
-			}else{
-				elems.add(a);
-				//Überprüfen ob das Set bereits berechnet wurde
-				if(!constraintSetRepository.containsSet(elems)){
-					res = unify2(elems, eq, oderConstraints, fc, parallel, rekTiefe, new HashSet<>(methodSignatureConstraint));
+				//res = unify2(newElemsOrig, newEqOrig, newOderConstraintsOrig, fc, parallel, rekTiefe);
+				
+				/* FORK ANFANG */
+				synchronized (this) {
+					writeLog("wait "+ forkOrig.thNo);
+					noOfThread--;
+					res = forkOrig.join();
+					synchronized (usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+					}
+					//noOfThread++;
+					forkOrig.writeLog("final Orig 1");
+					forkOrig.closeLogFile();
+					//Set<Set<UnifyPair>> fork_res = forkOrig.join();
+					writeLog("JoinOrig " + new Integer(forkOrig.thNo).toString());
+					//noOfThread--; an das Ende von compute verschoben 
+					//add_res.add(fork_res);
+				};
+				/* FORK ENDE */
+				
+				forks.forEach(x -> writeLog("wait: " + x.thNo));
+				for(TypeUnify2Task fork : forks) {
+					synchronized (this) {
+						noOfThread--;
+						Set<Set<UnifyPair>> fork_res = fork.join();
+						synchronized (usedTasks) {
+							if (this.myIsCancelled()) {
+								return new HashSet<>();
+							}
+						}
+						//noOfThread++;
+						writeLog("Join " + new Integer(fork.thNo).toString());
+						//noOfThread--; an das Ende von compute verschoben
+						writeLog("fork_res: " + fork_res.toString());
+						writeLog(new Boolean((isUndefinedPairSetSet(fork_res))).toString());
+						add_res.add(fork_res);
+						if (!isUndefinedPairSetSet(fork_res)) {
+							aParDef.add(fork.getNextSetElement());
+						}
+						fork.writeLog("final 1");
+						fork.closeLogFile();
+					};
 				}
-			}
+				//noOfThread++;
+			} else {
+			if(parallel && (variance == -1) && noOfThread <= MaxNoOfThreads) {
+				Set<TypeUnify2Task> forks = new HashSet<>();
+				Set<UnifyPair> newEqOrig = new HashSet<>(eq);
+				Set<Set<UnifyPair>> newElemsOrig = new HashSet<>(elems);
+				List<Set<Constraint<UnifyPair>>> newOderConstraintsOrig = new ArrayList<>(oderConstraints);
+				newElemsOrig.add(a);
+				
+				/* FORK ANFANG */
+				TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, new HashSet<>(methodSignatureConstraint));
+				//forks.add(forkOrig);
+				synchronized(usedTasks) {
+					if (this.myIsCancelled()) {
+						return new HashSet<>();
+					}
+					forkOrig.fork();
+				}
+				/* FORK ENDE */
+				
+				synchronized (this) {
+					writeLog("a in " + variance + " "+ a);
+					writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+				}
+				while (!nextSetasList.isEmpty()) {
+					Set<UnifyPair> nSaL = nextSetasList.remove(0);
+					synchronized (this) { //nextSetasList.remove(nSaL);
+						writeLog("-1 RM" + nSaL.toString());
+					}
+					
+					if (!oderConstraint) {
+						/* statistics sameEq wird nicht betrachtet ANGFANG
+						//ueberpruefung ob zu a =. ty \in nSaL in sameEqSet ein Widerspruch besteht
+						if (!sameEqSet.isEmpty() && !checkNoContradiction(nSaL, sameEqSet, result)) {
+							nSaL = null;
+							noShortendElements++;
+							continue;
+						}
+						statistics sameEq wird nicht betrachtet ENDE */
+					}
+					else {
+						nextSetasListOderConstraints.add(((Constraint<UnifyPair>)nSaL).getExtendConstraint());
+					}
+					Set<UnifyPair> newEq = new HashSet<>(eq);
+					Set<Set<UnifyPair>> newElems = new HashSet<>(elems);
+					List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
+					newElems.add(nSaL);
+					TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, new HashSet<>(methodSignatureConstraint));
+					forks.add(fork);
+					synchronized(usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+						fork.fork();
+					}
+				}
+				//res = unify2(newElemsOrig, newEqOrig, newOderConstraintsOrig, fc, parallel, rekTiefe);
+				
+				/* FORK ANFANG */
+				synchronized (this) {
+					writeLog("wait "+ forkOrig.thNo);
+					noOfThread--;
+					res = forkOrig.join();
+					synchronized (usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+					}
+					//noOfThread++;
+					forkOrig.writeLog("final Orig -1");
+					forkOrig.closeLogFile();
+					//Set<Set<UnifyPair>> fork_res = forkOrig.join();
+					writeLog("JoinOrig " + new Integer(forkOrig.thNo).toString());
+					//noOfThread--; an das Ende von compute verschoben 
+					//add_res.add(fork_res);
+				};
+				/* FORK ENDE */
+				
+				forks.forEach(x -> writeLog("wait: " + x.thNo));
+				for(TypeUnify2Task fork : forks) {
+					synchronized (this) {
+						noOfThread--;
+						Set<Set<UnifyPair>> fork_res = fork.join();
+						synchronized (usedTasks) {
+							if (this.myIsCancelled()) {
+								return new HashSet<>();
+							}
+						}
+						//noOfThread++;
+						writeLog("Join " + new Integer(fork.thNo).toString());
+						//noOfThread--; an das Ende von compute verschoben 
+						writeLog("fork_res: " + fork_res.toString());
+						writeLog(new Boolean((isUndefinedPairSetSet(fork_res))).toString());
+						add_res.add(fork_res);
+						if (!isUndefinedPairSetSet(fork_res)) {
+							aParDef.add(fork.getNextSetElement());
+						}
+						fork.writeLog("final -1");
+						fork.closeLogFile();
+					};
+				}
+				//noOfThread++;
+		    } else {
+		    if(parallel && (variance == 2) && noOfThread <= MaxNoOfThreads) {
+		    	writeLog("var2einstieg");
+		    	Set<TypeUnify2Task> forks = new HashSet<>();
+		    	Set<UnifyPair> newEqOrig = new HashSet<>(eq);
+		    	Set<Set<UnifyPair>> newElemsOrig = new HashSet<>(elems);
+		    	List<Set<Constraint<UnifyPair>>> newOderConstraintsOrig = new ArrayList<>(oderConstraints);
+		    	newElemsOrig.add(a);
+				
+				/* FORK ANFANG */
+		    	TypeUnify2Task forkOrig = new TypeUnify2Task(newElemsOrig, newEqOrig, newOderConstraintsOrig, a, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, new HashSet<>(methodSignatureConstraint));
+		    	//forks.add(forkOrig);
+		    	synchronized(usedTasks) {
+					if (this.myIsCancelled()) {
+						return new HashSet<>();
+					}
+					forkOrig.fork();
+		    	}
+		    	/* FORK ENDE */
+		    	
+		    	synchronized (this) {
+					writeLog("a in " + variance + " "+ a);
+					writeLog("nextSetasListRest: " + nextSetasListRest.toString());
+				}
+		    	while (!nextSetasList.isEmpty()) {
+		    		Set<UnifyPair> nSaL = nextSetasList.remove(0);
+		    		//nextSetasList.remove(nSaL); //PL einkommentiert 20-02-03
+		    		Set<UnifyPair> newEq = new HashSet<>(eq);
+		    		Set<Set<UnifyPair>> newElems = new HashSet<>(elems);
+		    		List<Set<Constraint<UnifyPair>>> newOderConstraints = new ArrayList<>(oderConstraints);
+		    		newElems.add(nSaL);
+		    		TypeUnify2Task fork = new TypeUnify2Task(newElems, newEq, newOderConstraints, nSaL, fc, parallel, logFile, log, rekTiefe, urm, usedTasks, methodSignatureConstraint);
+		    		forks.add(fork);
+		    		synchronized(usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+						fork.fork();
+		    		}
+		    	}
+		    	//res = unify2(newElemsOrig, newEqOrig, newOderConstraintsOrig, fc, parallel, rekTiefe);
+		    	
+		    	/* FORK ANFANG */
+		    	synchronized (this) {
+		    		writeLog("wait "+ forkOrig.thNo);
+		    		noOfThread--;
+					res = forkOrig.join();
+					synchronized (usedTasks) {
+						if (this.myIsCancelled()) {
+							return new HashSet<>();
+						}
+					}
+					//noOfThread++;
+					forkOrig.writeLog("final Orig 2");
+					forkOrig.closeLogFile();
+					//Set<Set<UnifyPair>> fork_res = forkOrig.join();
+					writeLog("JoinOrig " + new Integer(forkOrig.thNo).toString());
+					//noOfThread--; an das Ende von compute verschoben 
+					//add_res.add(fork_res); //vermutlich falsch
+				};
+				/* FORK ENDE */
+		    	forks.forEach(x -> writeLog("wait: " + x.thNo));
+		    	for(TypeUnify2Task fork : forks) {
+		    		synchronized (this) {
+		    			noOfThread--;
+						Set<Set<UnifyPair>> fork_res = fork.join();
+						synchronized (usedTasks) {
+							if (this.myIsCancelled()) {
+								return new HashSet<>();
+							}
+						}
+						//noOfThread++;
+						writeLog("Join " + new Integer(fork.thNo).toString());
+						//noOfThread--; an das Ende von compute verschoben 
+						add_res.add(fork_res);
+						fork.writeLog("final 2");
+						fork.closeLogFile();
+					};
+				} 
+		    	//noOfThread++;	
+		    } else {//parallel = false oder MaxNoOfThreads ist erreicht, sequentiell weiterarbeiten
+				elems.add(a); //PL 2019-01-16 muss das wirklich hin steht schon in Zeile 859 ja braucht man siehe Zeile 859
+				res = unify2(elems, eq, oderConstraints, fc, parallel, rekTiefe, new HashSet<>(methodSignatureConstraint));
+		    }}}
 			
 			//Ab hier alle parallele Berechnungen wieder zusammengeführt.
 			//if (hilf == 1)
@@ -2229,6 +2612,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>>  {
 		if (log && finalresult) {
 			try {
 				logFile.write("Thread no.:" + thNo + "\n");
+				logFile.write("noOfThread:" + noOfThread + "\n");
 				logFile.write("parallel:" + parallel + "\n");
 				logFile.write(str+"\n\n");
 				logFile.flush();

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyResultListener.java

@@ -0,0 +1,7 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+public interface UnifyResultListener {
+
+	void onNewTypeResultFound(UnifyResultEvent evt);
+
+}

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyResultListenerImpl.java

@@ -0,0 +1,21 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import java.sql.ResultSet;
+import java.util.ArrayList;
+import java.util.List;
+
+import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
+
+public class UnifyResultListenerImpl implements UnifyResultListener {
+
+	List<ResultSet> results = new ArrayList<>();
+	
+	public synchronized void onNewTypeResultFound(UnifyResultEvent evt) {
+		results.addAll(evt.getNewTypeResult());
+	}
+	
+	public List<ResultSet> getResults() {
+		return results;
+	}
+
+}

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyResultModel.java

@@ -0,0 +1,41 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import java.sql.ResultSet;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
+import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
+import de.dhbwstuttgart.typeinference.unify.model.PairOperator;
+import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
+
+public class UnifyResultModel {
+	
+	ConstraintSet<de.dhbwstuttgart.typeinference.constraints.Pair> cons;
+	
+	IFiniteClosure fc;
+	
+	public UnifyResultModel(ConstraintSet<de.dhbwstuttgart.typeinference.constraints.Pair> cons,
+					 IFiniteClosure fc) {
+		this.cons = cons;
+		this.fc = fc;
+	}
+	
+	private List<UnifyResultListener> listeners = new ArrayList<>();
+	
+	public void addUnifyResultListener(UnifyResultListener listenerToAdd) {
+		listeners.add(listenerToAdd);
+	}
+
+	public void removeUnifyResultListener(UnifyResultListener listenerToRemove) {
+		listeners.remove(listenerToRemove);
+	}
+	
+	public void notify(Set<Set<UnifyPair>> eqPrimePrimeSet) {
+
+	}
+}

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyResultModelParallel.java

@@ -1,51 +0,0 @@
-package de.dhbwstuttgart.typeinference.unify;
-
-import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
-import de.dhbwstuttgart.typeinference.constraints.Pair;
-import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
-import de.dhbwstuttgart.typeinference.unify.model.PairOperator;
-import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
-
-import java.util.*;
-import java.util.concurrent.ForkJoinPool;
-import java.util.stream.Collectors;
-
-public class UnifyResultModelParallel {
-    private ForkJoinPool pool;
-    private ConstraintSet<Pair> cons;
-    private IFiniteClosure fc;
-    private List<IUnifyResultListener> listeners = new ArrayList<>();
-
-    public UnifyResultModelParallel(ConstraintSet<Pair> cons, IFiniteClosure fc){
-        this.cons = cons;
-        this.fc = fc;
-    }
-
-    public void setPool(ForkJoinPool pool){
-        this.pool = pool;
-    }
-    public void addUnifyResultListener(IUnifyResultListener listenerToAdd) {
-        listeners.add(listenerToAdd);
-    }
-    public void removeUnifyResultListener(IUnifyResultListener listenerToRemove) {
-        listeners.remove(listenerToRemove);
-    }
-    public void notify(Set<Set<UnifyPair>> eqPrimePrimeSet){
-        pool.execute(()->{
-            Set<Set<UnifyPair>> eqPrimePrimeSetRet = eqPrimePrimeSet.stream().map(x -> {
-                Optional<Set<UnifyPair>> res = new RuleSet().subst(x.stream().map(y -> {
-                    if (y.getPairOp() == PairOperator.SMALLERDOTWC) y.setPairOp(PairOperator.EQUALSDOT);
-                    return y; //alle Paare a <.? b erden durch a =. b ersetzt
-                }).collect(Collectors.toCollection(HashSet::new)));
-                if (res.isPresent()) {//wenn subst ein Erg liefert wurde was veraendert
-                    return new TypeUnifyTask().applyTypeUnificationRules(res.get(), fc);
-                }
-                else return x; //wenn nichts veraendert wurde wird x zurueckgegeben
-            }).collect(Collectors.toCollection(HashSet::new));
-
-            for (IUnifyResultListener listener : listeners) {
-                listener.onNewTypeResultFound(eqPrimePrimeSetRet);
-            }
-        });
-    }
-}

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModel.java

@@ -0,0 +1,18 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import java.util.ArrayList;
+
+public class UnifyTaskModel {
+
+	ArrayList<TypeUnifyTask> usedTasks = new ArrayList<>();
+	
+	public synchronized void add(TypeUnifyTask t) {
+		usedTasks.add(t);
+	}
+    
+    public synchronized void cancel() {
+    	for(TypeUnifyTask t : usedTasks) {
+    		t.myCancel(true);
+    	}
+    }
+}

src/main/java/de/dhbwstuttgart/typeinference/unify/UnifyTaskModelParallel.java

@@ -1,18 +0,0 @@
-package de.dhbwstuttgart.typeinference.unify;
-
-
-import java.util.concurrent.ForkJoinPool;
-
-public class UnifyTaskModelParallel {
-    private ForkJoinPool pool;
-
-    public void setPool(ForkJoinPool pool){
-        this.pool = pool;
-    }
-
-    public void cancel(){
-        if(this.pool != null){
-            this.pool.shutdown();
-        }
-    }
-}

src/main/java/de/dhbwstuttgart/typeinference/unify/model/PlaceholderType.java

@@ -1,10 +1,13 @@
 package de.dhbwstuttgart.typeinference.unify.model;
 
+import java.io.File;
+import java.io.FileWriter;
 import java.util.ArrayList;
 import java.util.Collection;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Random;
 import java.util.Set;
-import java.util.concurrent.ConcurrentHashMap;
 
 import de.dhbwstuttgart.typeinference.unify.distributeVariance;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
@@ -20,7 +23,7 @@ public final class PlaceholderType extends UnifyType{
 	 * Static list containing the names of all existing placeholders.
 	 * Used for generating fresh placeholders.
 	 */
-	public static final Set<String> EXISTING_PLACEHOLDERS = ConcurrentHashMap.newKeySet();
+	public static final ArrayList<String> EXISTING_PLACEHOLDERS = new ArrayList<String>();
 	
 	/**
 	 * Prefix of auto-generated placeholder names.
@@ -93,7 +96,7 @@ public final class PlaceholderType extends UnifyType{
 	 * A user could later instantiate a type using the same name that is equivalent to this type.
 	 * @return A fresh placeholder type.
 	 */
-	public static PlaceholderType freshPlaceholder() {
+	public synchronized static PlaceholderType freshPlaceholder() {
 		String name = nextName + (char) (rnd.nextInt(22) + 97); // Returns random char between 'a' and 'z'
 		// Add random chars while the name is in use.
 		while(EXISTING_PLACEHOLDERS.contains(name)) {

src/test/java/UnifyTest.java

@@ -2,8 +2,8 @@ import de.dhbwstuttgart.typeinference.constraints.Constraint;
 import de.dhbwstuttgart.typeinference.constraints.ConstraintSet;
 import de.dhbwstuttgart.typeinference.constraints.Pair;
 import de.dhbwstuttgart.typeinference.unify.TypeUnify;
-import de.dhbwstuttgart.typeinference.unify.UnifyResultModelParallel;
-import de.dhbwstuttgart.typeinference.unify.UnifyTaskModelParallel;
+import de.dhbwstuttgart.typeinference.unify.UnifyResultModel;
+import de.dhbwstuttgart.typeinference.unify.UnifyTaskModel;
 import de.dhbwstuttgart.typeinference.unify.interfaces.IFiniteClosure;
 import de.dhbwstuttgart.typeinference.unify.model.*;
 import org.apache.commons.io.output.NullWriter;
@@ -76,12 +76,13 @@ public class UnifyTest {
 
         TypeUnify unifyAlgo = new TypeUnify();
         ConstraintSet<Pair> cons = new ConstraintSet<>();
-        UnifyResultModelParallel urm = new UnifyResultModelParallel(cons, finiteClosure);
-        UnifyTaskModelParallel tasks = new UnifyTaskModelParallel();
+        UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+        UnifyTaskModel tasks = new UnifyTaskModel();
         Set<Set<UnifyPair>> solution = unifyAlgo.unify(undConstraints, oderConstraints, finiteClosure, new NullWriter(), false, urm, tasks);
         System.out.println(solution.size());
         //System.out.println(solution);
     }
+
     @Test
     public void basicMatrixTest(){
         UnifyType type1;
@@ -184,7 +185,7 @@ public class UnifyTest {
         type2 = new ReferenceType("Vector", new TypeParams(new ReferenceType("Vector", new TypeParams(new ReferenceType("Integer")))));
         constraints.add(new UnifyPair(type1, type2, PairOperator.SMALLER));
         //Vector<X> extends Object
-        type1 = new ReferenceType("Vector", new TypeParams(new PlaceholderType("X")));
+        type1 = new ReferenceType("Vector", new TypeParams(new ReferenceType("X")));
         type2 = new ReferenceType("Object");
         constraints.add(new UnifyPair(type1, type2, PairOperator.SMALLER));
         //Integer extends Object
@@ -195,8 +196,8 @@ public class UnifyTest {
 
         TypeUnify unifyAlgo = new TypeUnify();
         ConstraintSet< Pair> cons = new ConstraintSet<>();
-        UnifyResultModelParallel urm = new UnifyResultModelParallel(cons, finiteClosure);
-        UnifyTaskModelParallel tasks = new UnifyTaskModelParallel();
+        UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+        UnifyTaskModel tasks = new UnifyTaskModel();
         Set<Set<UnifyPair>> solution = unifyAlgo.unify(undConstraints, oderConstraints, finiteClosure, new NullWriter(), false, urm, tasks);
         System.out.println(solution.size());
     }
@@ -671,8 +672,8 @@ public class UnifyTest {
         FiniteClosure finiteClosure = new FiniteClosure(fcConstraints, new NullWriter());
         TypeUnify unifyAlgo = new TypeUnify();
         ConstraintSet< Pair> cons = new ConstraintSet<>();
-        UnifyResultModelParallel urm = new UnifyResultModelParallel(cons, finiteClosure);
-        UnifyTaskModelParallel tasks = new UnifyTaskModelParallel();
+        UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+        UnifyTaskModel tasks = new UnifyTaskModel();
         Set<Set<UnifyPair>> solution = unifyAlgo.unify(undConstraints, oderConstraints, finiteClosure, new NullWriter(), false, urm, tasks);
         System.out.println(solution.size());
     }
@@ -1232,8 +1233,8 @@ public class UnifyTest {
         FiniteClosure finiteClosure = new FiniteClosure(fcConstraints, new NullWriter());
         TypeUnify unifyAlgo = new TypeUnify();
         ConstraintSet< Pair> cons = new ConstraintSet<>();
-        UnifyResultModelParallel urm = new UnifyResultModelParallel(cons, finiteClosure);
-        UnifyTaskModelParallel tasks = new UnifyTaskModelParallel();
+        UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+        UnifyTaskModel tasks = new UnifyTaskModel();
         Set<Set<UnifyPair>> solution = unifyAlgo.unify(undConstraints, oderConstraints, finiteClosure, new NullWriter(), false, urm, tasks);
         System.out.println(solution.size());
     }
@@ -2097,8 +2098,8 @@ public class UnifyTest {
         FiniteClosure finiteClosure = new FiniteClosure(fcConstraints, new NullWriter());
         TypeUnify unifyAlgo = new TypeUnify();
         ConstraintSet< Pair> cons = new ConstraintSet<>();
-        UnifyResultModelParallel urm = new UnifyResultModelParallel(cons, finiteClosure);
-        UnifyTaskModelParallel tasks = new UnifyTaskModelParallel();
+        UnifyResultModel urm = new UnifyResultModel(cons, finiteClosure);
+        UnifyTaskModel tasks = new UnifyTaskModel();
         Set<Set<UnifyPair>> solution = unifyAlgo.unify(undConstraints, oderConstraints, finiteClosure, new NullWriter(), false, urm, tasks);
         System.out.println(solution.size());
     }