feat: added Logger class, remove empty println start cleanup of computeCartesianRecursive

src/main/java/de/dhbwstuttgart/syntaxtree/factory/UnifyTypeFactory.java

@@ -194,7 +194,7 @@ public class UnifyTypeFactory {
         		&& ((PlaceholderType)lhs).isWildcardable() 
         		&&	(rhs = ret.getLhsType()) instanceof PlaceholderType) {
         	if (lhs.getName().equals("AQ")) {
-        		System.out.println("");
+        		// System.out.println("");
         	}
         	((PlaceholderType)rhs).enableWildcardtable();
         }
@@ -203,7 +203,7 @@ public class UnifyTypeFactory {
         		&& ((PlaceholderType)rhs).isWildcardable()
         		&&	(lhs = ret.getLhsType()) instanceof PlaceholderType) {
         	if (rhs.getName().equals("AQ")) {
-        		System.out.println("");
+        		// System.out.println("");
         	}
         	((PlaceholderType)lhs).enableWildcardtable();
         }

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

@@ -15,7 +15,8 @@ public class ConcurrentSetMergeTask<T> extends RecursiveTask<Set<T>> {
     return task.compute();
   }
 
-  private static final int THRESHOLD = 3;
+  private static final int LIST_THRESHOLD = 3;
+  private static final int ELEMENT_THRESHOLD = 1000;
 
   private final List<Set<T>> list;
   private final int start;
@@ -31,8 +32,16 @@ public class ConcurrentSetMergeTask<T> extends RecursiveTask<Set<T>> {
   protected Set<T> compute() {
     int size = end - start;
 
+    int totalElements = 0;
+    for (int i = start+1; i < end; i++) {
+      totalElements += list.get(i).size();
+    }
+
+    System.out.println("ConcurrentSetMerge? -> " + (size <= LIST_THRESHOLD || totalElements < ELEMENT_THRESHOLD ? "true" : "false"));
+
+
     // size will always be at least one
-    if (size <= THRESHOLD) {
+    if (true || size <= LIST_THRESHOLD || totalElements < ELEMENT_THRESHOLD) {
       Set<T> result = this.list.get(start);
       for (int i = start+1; i < end; i++) {
         result.addAll(list.get(i));

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

@@ -22,6 +22,7 @@ import de.dhbwstuttgart.typeinference.unify.model.Unifier;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
 import de.dhbwstuttgart.typeinference.unify.model.UnifyType;
 import de.dhbwstuttgart.typeinference.unify.model.WildcardType;
+import de.dhbwstuttgart.util.Logger;
 import de.dhbwstuttgart.util.Pair;
 import java.io.File;
 import java.io.FileWriter;
@@ -657,82 +658,84 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
    */
   Set<Set<UnifyPair>> computeCartesianRecursive(ArrayList<Set<? extends Set<UnifyPair>>> topLevelSets, Set<UnifyPair> eq, List<Set<Constraint<UnifyPair>>> oderConstraints, IFiniteClosure fc, boolean parallel, int rekTiefe, Set<UnifyPair> methodSignatureConstraint) {
 
-    //oneElems: Alle 1-elementigen Mengen, die nur ein Paar
-    //a <. theta, theta <. a oder a =. theta enthalten
-    Set<Set<UnifyPair>> oneElems = new HashSet<>();
-    oneElems.addAll(topLevelSets.stream()
-      .filter(x -> x.size() == 1)
-      .map(y -> y.stream().findFirst().get())
-      .collect(Collectors.toCollection(HashSet::new)));
-    oneElems.forEach(x -> {
+    Logger.print("Start computeCartesianRecursive with " + topLevelSets.size() + " topLevelSets");
+
+    Set<Set<UnifyPair>> singleElementSets = TypeUnifyTaskHelper.getSingleElementSets(topLevelSets);
+    singleElementSets.forEach(x -> {
       if (x instanceof Constraint)
         methodSignatureConstraint.addAll(((Constraint<UnifyPair>) x).getmethodSignatureConstraint());
     });
-    //optNextSet: Eine mehrelementige Menge, wenn vorhanden
-    Optional<Set<? extends Set<UnifyPair>>> optNextSet = topLevelSets.stream().filter(x -> x.size() > 1).findAny();
 
-    if (!optNextSet.isPresent()) {//Alle Elemente sind 1-elementig
-      Set<Set<UnifyPair>> result = unify2(oneElems, eq, oderConstraints, fc, parallel, rekTiefe, methodSignatureConstraint);
-      return result;
+    /*
+     * @var optionalAnyMultiElementSet Eine mehrelementige Menge, wenn vorhanden
+     */
+    Optional<Set<? extends Set<UnifyPair>>> optionalAnyMultiElementSet = topLevelSets.stream().filter(x -> x.size() > 1).findAny();
+    if (optionalAnyMultiElementSet.isEmpty()) {
+      // Alle Elemente sind 1-elementig
+      return unify2(singleElementSets, eq, oderConstraints, fc, parallel, rekTiefe, methodSignatureConstraint);
     }
 
-    Set<? extends Set<UnifyPair>> nextSet = optNextSet.get();
+    /*
+     *	@var nextSet is any set with multiple elements
+     */
+    Set<? extends Set<UnifyPair>> nextSet = optionalAnyMultiElementSet.get();
     //writeLog("nextSet: " + nextSet.toString());
-    List<Set<UnifyPair>> nextSetasList = new ArrayList<>(nextSet);
+    List<Set<UnifyPair>> nextSetAsList = new ArrayList<>(nextSet);
 		/*
 		try {
-		//List<Set<UnifyPair>> 
+		//List<Set<UnifyPair>>
 			//nextSetasList = oup.sortedCopy(nextSet);//new ArrayList<>(nextSet);
 		}
 		catch (java.lang.IllegalArgumentException e) {
 			System.out.print("");
 		}
 		*/
-    Set<Set<UnifyPair>> result = new HashSet<>();
-    int variance = 0;
 
-    /* Varianzbestimmung Anfang
-     * Oderconstraint, wenn entweder kein Basepair oder unterschiedliche Basepairs => oderConstraint = true;
+    // check if all elements of nextSet have the same base
+    boolean hasSameBase;
+    if (nextSetAsList.isEmpty()) {
+      hasSameBase = false;
+    }
+    else {
+      hasSameBase = true;
+      UnifyPair firstBasePair = null;
+      for (var unifyPair : nextSetAsList.getFirst().stream().toList()) {
+        if (firstBasePair == null) {
+          firstBasePair = unifyPair.getBasePair();
+          if (firstBasePair == null) {
+            hasSameBase = false;
+            break;
+          }
+        }
+        else if (unifyPair.getBasePair() == null || !unifyPair.getBasePair().equals(firstBasePair)) {
+          hasSameBase = false;
+          break;
+        }
+      }
+    }
+
+    /*
+     * oderConstraint = true => entweder existiert kein Basepair oder unterschiedliche Basepairs
+     */
+    boolean oderConstraint = !hasSameBase;
+
+    /* Varianzbestimmung
      * 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;
-
-    if (fstBasePair != null) {
-      Boolean sameBase = true;
-      for (UnifyPair ele : nextSetasList.get(0)) {//check ob a <. ty base oder ob Ueberladung
-        sameBase = sameBase && ele.getBasePair() != null && ele.getBasePair().equals(fstBasePair);
-      }
-      if (sameBase) {                                                                                                                 //angefuegt PL 2020-02-30
-        Optional<Integer> xi = nextSetasList.stream().map(x -> x.stream().filter(y -> (y.getLhsType() instanceof PlaceholderType && !(y.getRhsType() instanceof PlaceholderType)))
-            .filter(z -> ((PlaceholderType) z.getLhsType()).getVariance() != 0)
-            .map(c -> ((PlaceholderType) c.getLhsType()).getVariance())
-            .reduce((a, b) -> {
-              if (a == b) return a;
-              else return 0;
-            })) //2 kommt insbesondere bei Oder-Constraints vor
-          .filter(d -> d.isPresent())
-          .map(e -> e.get())
-          .findAny();
-        if (xi.isPresent()) {
-          variance = xi.get();
-        }
-      } else {
-        oderConstraint = true;
-      }
-    } else {
-      oderConstraint = true;
+    int variance;
+    if (!oderConstraint) {
+      variance = TypeUnifyTaskHelper.calculateVariance(nextSetAsList);
     }
-
-    //Varianz-Bestimmung Oder-Constraints
-    if (oderConstraint) {
-      if (printtag) System.out.println("nextSetasList " + nextSetasList);
+    else {
+      //Varianz-Bestimmung Oder-Constraints
+      if (printtag) {
+        System.out.println("nextSetasList " + nextSetAsList);
+      }
       Optional<Integer> optVariance =
-        nextSetasList.iterator()
-          .next()
+        nextSetAsList
+          .getFirst()
           .stream()
           .filter(x -> x.getGroundBasePair().getLhsType() instanceof PlaceholderType &&
             !(x.getRhsType() instanceof PlaceholderType) &&
@@ -749,10 +752,11 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
       //Bei Varianz = 2 werden alle Elemente des Kartesischen Produkts abgearbeitet
       variance = optVariance.isPresent() ? optVariance.get() : 2;
     }
-    /* Varianzbestimmung Ende */
+
+    // TODO: continue cleaning code and move some to TypeUnifyTaskHelper
 
     //writeLog("nextSetasList: " + nextSetasList.toString());
-    Set<UnifyPair> nextSetElem = nextSetasList.get(0);
+    Set<UnifyPair> nextSetElem = nextSetAsList.get(0);
     //writeLog("BasePair1: " + nextSetElem + " " + nextSetElem.iterator().next().getBasePair());
 
     /* sameEqSet-Bestimmung: Wenn a = ty \in  nextSet dann enthaelt sameEqSet
@@ -784,7 +788,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
           tyVar = origPair.getRhsType();
         }
         UnifyType tyVarEF = tyVar;
-        sameEqSet = oneElems.stream().map(xx -> xx.iterator().next())
+        sameEqSet = singleElementSets.stream().map(xx -> xx.iterator().next())
           .filter(x -> (((x.getLhsType().equals(tyVarEF) && !(x.getRhsType() instanceof PlaceholderType))
             || (x.getRhsType().equals(tyVarEF) && !(x.getLhsType() instanceof PlaceholderType)))))
           .collect(Collectors.toCollection(HashSet::new));
@@ -792,8 +796,10 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
     }
     /* sameEqSet-Bestimmung Ende */
 
+    Set<Set<UnifyPair>> result = new HashSet<>();
+
     Set<UnifyPair> a = null;
-    while (nextSetasList.size() > 0) {
+    while (nextSetAsList.size() > 0) {
       Set<UnifyPair> a_last = a;
 
       /* Liste der Faelle für die parallele Verarbeitung
@@ -811,16 +817,16 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
       List<Set<UnifyPair>> nextSetasListOderConstraints = new ArrayList<>();
 
       writeLog("nextSet: " + nextSet.toString());
-      writeLog("nextSetasList: " + nextSetasList.toString());
+      writeLog("nextSetasList: " + nextSetAsList.toString());
       if (variance == 1) {
-        a = oup.max(nextSetasList.iterator());
+        a = oup.max(nextSetAsList.iterator());
         writeLog("Max: a in " + variance + " " + a);
-        nextSetasList.remove(a);
+        nextSetAsList.remove(a);
         if (oderConstraint) {
           nextSetasListOderConstraints.add(((Constraint<UnifyPair>) a).getExtendConstraint());
         }
         writeLog("nextSetasListOderConstraints 1: " + nextSetasListOderConstraints);
-        nextSetasListRest = new ArrayList<>(nextSetasList);
+        nextSetasListRest = new ArrayList<>(nextSetAsList);
         Iterator<Set<UnifyPair>> nextSetasListItRest = new ArrayList<Set<UnifyPair>>(nextSetasListRest).iterator();
         while (nextSetasListItRest.hasNext()) {
           Set<UnifyPair> a_next = nextSetasListItRest.next();
@@ -834,14 +840,14 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
         //nur für diese wird parallele Berechnung angestossen.
         nextSetasListRest = oup.maxElements(nextSetasListRest);
       } else if (variance == -1) {
-        a = oup.min(nextSetasList.iterator());
+        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);
+        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();
@@ -854,27 +860,27 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
         //nur für diese wird parallele Berechnung angestossen.
         nextSetasListRest = oup.minElements(nextSetasListRest);
       } else if (variance == 2) {
-        a = nextSetasList.remove(0);
+        a = nextSetAsList.remove(0);
 
         //Fuer alle Elemente wird parallele Berechnung angestossen.
-        nextSetasListRest = new ArrayList<>(nextSetasList);
+        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());
+            a = oup.max(nextSetAsList.iterator());
           } else {
-            a = oup.min(nextSetasList.iterator());
+            a = oup.min(nextSetAsList.iterator());
           }
-          nextSetasList.remove(a);
+          nextSetAsList.remove(a);
         } else {
           if (oderConstraint) {
-            a = oup.max(nextSetasList.iterator());
-            nextSetasList.remove(a);
+            a = oup.max(nextSetAsList.iterator());
+            nextSetAsList.remove(a);
             nextSetasListOderConstraints.add(((Constraint<UnifyPair>) a).getExtendConstraint());
           } else {
-            a = nextSetasList.remove(0);
+            a = nextSetAsList.remove(0);
           }
         }
       }
@@ -889,12 +895,13 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
       }
 
       i++;
-      Set<Set<UnifyPair>> elems = new HashSet<Set<UnifyPair>>(oneElems);
+      Set<Set<UnifyPair>> elems = new HashSet<Set<UnifyPair>>(singleElementSets);
       writeLog("a1: " + rekTiefe + "  " + "variance:  " + variance + " " + a.toString() + "\n");
 
       //Ergebnisvariable für den aktuelle Thread
       Set<Set<UnifyPair>> res = new HashSet<>();
 
+
       //Menge der Ergebnisse der geforkten Threads
       Set<Set<Set<UnifyPair>>> add_res = new HashSet<>();
 
@@ -938,7 +945,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
         while (!nextSetasListRest.isEmpty()) {
           Set<UnifyPair> nSaL = nextSetasListRest.remove(0);
           synchronized (this) {
-            nextSetasList.remove(nSaL);
+            nextSetAsList.remove(nSaL);
             writeLog("1 RM" + nSaL.toString());
           }
 
@@ -1030,7 +1037,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
           while (!nextSetasListRest.isEmpty()) {
             Set<UnifyPair> nSaL = nextSetasListRest.remove(0);
             synchronized (this) {
-              nextSetasList.remove(nSaL);
+              nextSetAsList.remove(nSaL);
               writeLog("-1 RM" + nSaL.toString());
             }
 
@@ -1131,7 +1138,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
             while (!nextSetasListRest.isEmpty()) {
               methodSignatureConstraintForParallel.removeAll(((Constraint<UnifyPair>) nSaL).getmethodSignatureConstraint());
               nSaL = nextSetasListRest.remove(0);
-              nextSetasList.remove(nSaL); //PL einkommentiert 20-02-03
+              nextSetAsList.remove(nSaL); //PL einkommentiert 20-02-03
               methodSignatureConstraintForParallel.addAll(((Constraint<UnifyPair>) nSaL).getmethodSignatureConstraint());
               Set<UnifyPair> newEq = new HashSet<>(eq);
               Set<Set<UnifyPair>> newElems = new HashSet<>(elems);
@@ -1207,7 +1214,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
 
             //Alle Variablen bestimmen die nicht hinzugefügt wurden in a
             //PL 2018-12-28: Hier gab es eine ClassCastException, war nicht reproduzierbar
-            System.out.println("");
+            // System.out.println("");
             List<PlaceholderType> vars_a =
               a.stream().filter(x -> ((x.getLhsType().getName().equals(x.getBasePair().getLhsType().getName())
                   && (x.getLhsType() instanceof PlaceholderType) && (x.getBasePair().getLhsType() instanceof PlaceholderType))
@@ -1297,50 +1304,45 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
       }
 
       if (parallel) {
-        List<Set<Set<UnifyPair>>> partialResults = new ArrayList<>();
         for (Set<Set<UnifyPair>> par_res : add_res) {
           if (!isUndefinedPairSetSet(par_res) && isUndefinedPairSetSet(result)) {
             //wenn korrektes Ergebnis gefunden alle Fehlerfaelle loeschen
-            // result = par_res;
-            partialResults = new ArrayList<>();
-            partialResults.add(par_res);
+            result = par_res;
             if (!par_res.isEmpty() && par_res.iterator().next() instanceof WildcardType) {
               System.out.println("");
             }
-          } else {
+          }
+          else {
             if ((isUndefinedPairSetSet(par_res) && isUndefinedPairSetSet(result))
               || (!isUndefinedPairSetSet(par_res) && !isUndefinedPairSetSet(result))
               || result.isEmpty()) {
               //alle Fehlerfaelle und alle korrekten Ergebnis jeweils adden
               writeLog("RES var1 ADD:" + result.toString() + " " + par_res.toString());
-              // result.addAll(par_res);
-              partialResults.add(par_res);
+              result.addAll(par_res);
             }
           }
         }
-
-        result = ConcurrentSetMergeTask.merge(partialResults);
         //break;
       }
 
       /* auskommentiert um alle Max und min Betrachtung auszuschalten ANFANG */
       if (!result.isEmpty() && (!isUndefinedPairSetSet(res) || !aParDef.isEmpty())) {
-        if (nextSetasList.iterator().hasNext() && nextSetasList.iterator().next().stream().filter(x -> x.getLhsType().getName().equals("B")).findFirst().isPresent() && nextSetasList.size() > 1)
+        if (nextSetAsList.iterator().hasNext() && nextSetAsList.iterator().next().stream().filter(x -> x.getLhsType().getName().equals("B")).findFirst().isPresent() && nextSetAsList.size() > 1)
           System.out.print("");
-        Iterator<Set<UnifyPair>> nextSetasListIt = new ArrayList<Set<UnifyPair>>(nextSetasList).iterator();
+        Iterator<Set<UnifyPair>> nextSetasListIt = new ArrayList<Set<UnifyPair>>(nextSetAsList).iterator();
         if (variance == 1) {
-          System.out.println("");
+          // System.out.println("");
           writeLog("a: " + rekTiefe + " variance: " + variance + a.toString());
           writeLog("aParDef: " + aParDef.toString());
           aParDef.add(a);
           Iterator<Set<UnifyPair>> aParDefIt = aParDef.iterator();
           if (oderConstraint) {
-            nextSetasList.removeAll(nextSetasListOderConstraints);
+            nextSetAsList.removeAll(nextSetasListOderConstraints);
             nextSetasListOderConstraints = new ArrayList<>();
             writeLog("Removed: " + nextSetasListOderConstraints);
             while (aParDefIt.hasNext()) {
               Set<UnifyPair> a_new = aParDefIt.next();
-              List<Set<UnifyPair>> smallerSetasList = oup.smallerThan(a_new, nextSetasList);
+              List<Set<UnifyPair>> smallerSetasList = oup.smallerThan(a_new, nextSetAsList);
               writeLog("smallerSetasList: " + smallerSetasList);
               List<Set<UnifyPair>> notInherited = smallerSetasList.stream()
                 .filter(x -> !((Constraint<UnifyPair>) x).isInherited() && !((Constraint<UnifyPair>) x).isImplemented())
@@ -1353,39 +1355,39 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
               List<Set<UnifyPair>> erased = new ArrayList<>(smallerSetasList);
               writeLog("notErased: " + notErased + "\n");
               erased.removeAll(notErased);
-              nextSetasList.removeAll(erased);
+              nextSetAsList.removeAll(erased);
 
               writeLog("Removed: " + erased);
 
-              writeLog("Not Removed: " + nextSetasList);
+              writeLog("Not Removed: " + nextSetAsList);
 
             }
           } else {
             while (aParDefIt.hasNext()) {
               //nextSetasListIt = nextSetasList.iterator(); Sollte eingefuegt werden PL 2020-04-28
               Set<UnifyPair> a_new = aParDefIt.next();
-              List<Set<UnifyPair>> erased = oup.smallerEqThan(a_new, nextSetasList);
-              nextSetasList.removeAll(erased);
+              List<Set<UnifyPair>> erased = oup.smallerEqThan(a_new, nextSetAsList);
+              nextSetAsList.removeAll(erased);
 
               writeLog("Removed: " + erased);
 
-              writeLog("Not Removed: " + nextSetasList);
+              writeLog("Not Removed: " + nextSetAsList);
             }
           }
         } else {
           if (variance == -1) {
-            System.out.println("");
+            // System.out.println("");
             writeLog("a: " + rekTiefe + " variance: " + variance + a.toString());
             writeLog("aParDef: " + aParDef.toString());
             aParDef.add(a);
             Iterator<Set<UnifyPair>> aParDefIt = aParDef.iterator();
             if (oderConstraint) {
-              nextSetasList.removeAll(nextSetasListOderConstraints);
+              nextSetAsList.removeAll(nextSetasListOderConstraints);
               writeLog("Removed: " + nextSetasListOderConstraints);
               nextSetasListOderConstraints = new ArrayList<>();
               while (aParDefIt.hasNext()) {
                 Set<UnifyPair> a_new = aParDefIt.next();
-                List<Set<UnifyPair>> greaterSetasList = oup.greaterThan(a_new, nextSetasList);
+                List<Set<UnifyPair>> greaterSetasList = oup.greaterThan(a_new, nextSetAsList);
 
                 //a_new muss hingefuegt werden, wenn es nicht vererbt ist, dann wird es spaeter wieder geloescht
                 if (!((Constraint<UnifyPair>) a_new).isInherited()) {
@@ -1412,24 +1414,24 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
 
                 List<Set<UnifyPair>> erased = new ArrayList<>(greaterSetasList);
                 erased.removeAll(notErased);
-                nextSetasList.removeAll(erased);
+                nextSetAsList.removeAll(erased);
 
                 writeLog("Removed: " + erased);
 
-                writeLog("Not Removed: " + nextSetasList);
+                writeLog("Not Removed: " + nextSetAsList);
 
               }
             } else {
               while (aParDefIt.hasNext()) {
                 //nextSetasListIt = nextSetasList.iterator(); Sollte eingefuegt werden PL 2020-04-28
                 Set<UnifyPair> a_new = aParDefIt.next();
-                List<Set<UnifyPair>> erased = oup.greaterEqThan(a_new, nextSetasList);
+                List<Set<UnifyPair>> erased = oup.greaterEqThan(a_new, nextSetAsList);
 
-                nextSetasList.removeAll(erased);
+                nextSetAsList.removeAll(erased);
 
                 writeLog("Removed: " + erased);
 
-                writeLog("Not Removed: " + nextSetasList);
+                writeLog("Not Removed: " + nextSetAsList);
               }
             }
           } else {
@@ -1438,10 +1440,10 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
               if (!oderConstraint) {
                 break;
               } else {
-                nextSetasList.removeAll(nextSetasListOderConstraints);
+                nextSetAsList.removeAll(nextSetasListOderConstraints);
                 nextSetasListOderConstraints = new ArrayList<>();
                 writeLog("Removed: " + nextSetasListOderConstraints);
-                List<Set<UnifyPair>> smallerSetasList = oup.smallerThan(a, nextSetasList);
+                List<Set<UnifyPair>> smallerSetasList = oup.smallerThan(a, nextSetAsList);
                 List<Set<UnifyPair>> notInherited = smallerSetasList.stream()
                   .filter(x -> !((Constraint<UnifyPair>) x).isInherited())
                   .collect(Collectors.toCollection(ArrayList::new));
@@ -1451,11 +1453,11 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
                 });
                 List<Set<UnifyPair>> erased = new ArrayList<>(smallerSetasList);
                 erased.removeAll(notErased);
-                nextSetasList.removeAll(erased);
+                nextSetAsList.removeAll(erased);
 
                 writeLog("Removed: " + erased);
 
-                writeLog("Not Removed: " + nextSetasList);
+                writeLog("Not Removed: " + nextSetAsList);
 
               }
 
@@ -1503,7 +1505,7 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
           //.filter(y -> abhSubst.contains(y))
           .collect(Collectors.toCollection(HashSet::new));
         //Set<PlaceholderType> vars = durchschnitt.stream().map(x -> (PlaceholderType)x.getLhsType()).collect(Collectors.toCollection(HashSet::new));
-        int len = nextSetasList.size();
+        int len = nextSetAsList.size();
         Set<UnifyPair> undefRes = res.stream().reduce((y, z) -> {
           y.addAll(z);
           return y;
@@ -1519,9 +1521,9 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
         if (res.size() > 1) {
           System.out.println();
         }
-        writeLog("nextSetasList vor filter-Aufruf: " + nextSetasList);
+        writeLog("nextSetasList vor filter-Aufruf: " + nextSetAsList);
         if (!oderConstraint) {//PL 2023-02-08 eingefuegt: Bei oderconstraints sind Subststitutionen nicht als Substitutionen in idesem Sinne zu sehen
-          nextSetasList = nextSetasList.stream().filter(x -> {
+          nextSetAsList = nextSetAsList.stream().filter(x -> {
               //Boolean ret = false;
               //for (PlaceholderType var : vars) {
               //	ret = ret || x.stream().map(b -> b.getLhsType().equals(var)).reduce((c,d) -> c || d).get();
@@ -1530,8 +1532,8 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
             })//.filter(y -> couldBecorrect(reducedUndefResSubstGroundedBasePair, y)) //fuer testzwecke auskommentiert um nofstred zu bestimmen PL 2018-10-10
             .collect(Collectors.toCollection(ArrayList::new));
         }
-        writeLog("nextSetasList nach filter-Aufruf: " + nextSetasList);
-        nofstred = nextSetasList.size();
+        writeLog("nextSetasList nach filter-Aufruf: " + nextSetAsList);
+        nofstred = nextSetAsList.size();
         //NOCH NICHT korrekt PL 2018-10-12
         //nextSetasList = nextSetasList.stream().filter(y -> couldBecorrect(reducedUndefResSubstGroundedBasePair, y))
         //			.collect(Collectors.toCollection(ArrayList::new));
@@ -1540,15 +1542,15 @@ public class TypeUnifyTask extends RecursiveTask<Set<Set<UnifyPair>>> {
         writeLog("a2: " + rekTiefe + " " + a.toString());
         writeLog("Durchschnitt: " + durchschnitt.toString());
         writeLog("nextSet: " + nextSet.toString());
-        writeLog("nextSetasList: " + nextSetasList.toString());
+        writeLog("nextSetasList: " + nextSetAsList.toString());
         writeLog("Number first erased Elements (undef): " + (len - nofstred));
-        writeLog("Number second erased Elements (undef): " + (nofstred - nextSetasList.size()));
-        writeLog("Number erased Elements (undef): " + (len - nextSetasList.size()));
-        noAllErasedElements = noAllErasedElements + (len - nextSetasList.size());
+        writeLog("Number second erased Elements (undef): " + (nofstred - nextSetAsList.size()));
+        writeLog("Number erased Elements (undef): " + (len - nextSetAsList.size()));
+        noAllErasedElements = noAllErasedElements + (len - nextSetAsList.size());
         writeLog("Number of all erased Elements (undef): " + noAllErasedElements.toString());
         noBacktracking++;
         writeLog("Number of Backtracking: " + noBacktracking);
-        System.out.println("");
+        // System.out.println("");
       }
       //if (nextSetasList.size() == 0 && isUndefinedPairSetSet(result) && nextSet.size() > 1) {
       //	return result;

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

@@ -0,0 +1,68 @@
+package de.dhbwstuttgart.typeinference.unify;
+
+import de.dhbwstuttgart.typeinference.unify.model.PairOperator;
+import de.dhbwstuttgart.typeinference.unify.model.PlaceholderType;
+import de.dhbwstuttgart.typeinference.unify.model.UnifyPair;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+
+/**
+ * A collection of capsuled (and thus static) functions to split up large algorithms in TypeUnifyTask
+ */
+public class TypeUnifyTaskHelper {
+
+  /**
+   * Filter all topLevelSets for those with a single element that contain only one pair:
+   *   a <. theta,
+   *   theta <. a or
+   *   a =. theta
+   */
+  public static Set<Set<UnifyPair>> getSingleElementSets(ArrayList<Set<? extends Set<UnifyPair>>> topLevelSets) {
+    return topLevelSets.stream()
+      .filter(x -> x.size() == 1)
+      .map(y -> y.stream().findFirst().get()).collect(Collectors.toSet());
+  }
+
+  /**
+   * 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
+   */
+  public static int calculateVariance(List<Set<UnifyPair>> nextSetasList) {
+    Optional<Integer> xi = nextSetasList.stream().map(x -> x.stream().filter(y -> (y.getLhsType() instanceof PlaceholderType && !(y.getRhsType() instanceof PlaceholderType)))
+        .filter(z -> ((PlaceholderType) z.getLhsType()).getVariance() != 0)
+        .map(c -> ((PlaceholderType) c.getLhsType()).getVariance())
+        .reduce((a, b) -> {
+          if (a == b) return a;
+          else return 0;
+        })) //2 kommt insbesondere bei Oder-Constraints vor
+      .filter(d -> d.isPresent())
+      .map(e -> e.get())
+      .findAny();
+
+    return xi.orElse(0);
+  }
+
+  /**
+   * Find the first occurrence (if any) of a UnifyPair with operator EQUALSDOT while having
+   * one side equal to its base pair counterpart
+   */
+  public static Optional<UnifyPair> findEqualityConstrainedUnifyPair(Set<UnifyPair> nextSetElement) {
+    return nextSetElement.stream().filter(x ->
+        x.getPairOp()
+        .equals(PairOperator.EQUALSDOT))
+      .filter(x -> //Sicherstellen, dass bei a = ty a auch wirklich die gesuchte Typvariable ist
+        x.getLhsType()
+          .equals(x.getBasePair().getLhsType()) ||
+        x.getLhsType()
+          .equals(x.getBasePair().getRhsType())
+    ).findFirst();
+  }
+
+}

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

@@ -207,7 +207,7 @@ implements IFiniteClosure  {
 				result.add(new Pair<>(t, fBounded));
 			}
 			catch (StackOverflowError e) {
-				System.out.println("");
+				// System.out.println("");
 			}
 			
 			// if C<...> <* C<...> then ... (third case in definition of <*)
@@ -700,8 +700,8 @@ implements IFiniteClosure  {
 	
 	public int compare (UnifyType left, UnifyType right, PairOperator pairop) {
 		try {logFile.write("left: "+ left + " right: " + right + " pairop: " + pairop +"\n");} catch (IOException ie) {}
-		if (left.getName().equals("Matrix") || right.getName().equals("Matrix")) 
-			System.out.println("");
+		// if (left.getName().equals("Matrix") || right.getName().equals("Matrix"))
+		// 	System.out.println("");
 		/*
 		pairop = PairOperator.SMALLERDOTWC;
 		List<UnifyType> al = new ArrayList<>();

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

@@ -79,12 +79,12 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						&& (((ExtendsType)right).getExtendedType().getName().equals("java.util.Vector"))
 						&& (((ReferenceType)((ExtendsType)right).getExtendedType()).getTypeParams().iterator().next() instanceof ExtendsType)))
 				{
-					System.out.println("");
+					// System.out.println("");
 				}
 				if (((right instanceof SuperType) && (((SuperType)right).getSuperedType().getName().equals("java.lang.Object")))
 		||((left instanceof SuperType) && (((SuperType)left).getSuperedType().getName().equals("java.lang.Object"))))
 {
-						System.out.println("");
+						// System.out.println("");
 					}
 		}
 			else	 {
@@ -106,11 +106,11 @@ public class OrderingUnifyPair extends OrderingExtend<Set<UnifyPair>> {
 						&& (((ExtendsType)right).getExtendedType().getName().equals("java.util.Vector"))
 						&& (((ReferenceType)((ExtendsType)right).getExtendedType()).getTypeParams().iterator().next() instanceof ExtendsType)))
 				{
-					System.out.println("");
+					// System.out.println("");
 				}
 				if (right instanceof SuperType) 
 					{
-						System.out.println("");
+						// System.out.println("");
 					}
 			}
 				else	 {

src/main/java/de/dhbwstuttgart/util/Logger.java

@@ -0,0 +1,9 @@
+package de.dhbwstuttgart.util;
+
+public class Logger {
+
+  public static void print(String s) {
+    System.out.println(s);
+  }
+
+}