Separated the algorithm into two parts. Part 1 is the simplification of

the constraints and part 2 is generation of generics.

src/main/java/de/dhbwstuttgart/bytecode/TPHExtractor.java

@@ -106,7 +106,7 @@ public class TPHExtractor extends AbstractASTWalker {
 					if (inMethod)
 						methodAndTph.getPairs().add(ag);
 					allPairs.add(ag);
-					TPHConstraint con = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName(), Relation.EXTENDS);
+					TPHConstraint con = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName());
 					if(!containsConstraint(allCons,con))
 						allCons.add(con);
 //				}

src/main/java/de/dhbwstuttgart/bytecode/constraint/EqualConstraint.java

@@ -2,8 +2,8 @@ package de.dhbwstuttgart.bytecode.constraint;
 
 public class EqualConstraint extends TPHConstraint {
 
-	public EqualConstraint(String left, String right, Relation rel) {
+	public EqualConstraint(String left, String right) {
-		super(left, right, rel);
+		super(left, right, Relation.EQUAL);
 	}
 
 }

src/main/java/de/dhbwstuttgart/bytecode/constraint/ExtendsConstraint.java

@@ -2,8 +2,8 @@ package de.dhbwstuttgart.bytecode.constraint;
 
 public class ExtendsConstraint extends TPHConstraint {
 
-	public ExtendsConstraint(String left, String right, Relation rel) {
+	public ExtendsConstraint(String left, String right) {
-		super(left, right, rel);
+		super(left, right, Relation.EXTENDS);
 	}
 
 }

src/main/java/de/dhbwstuttgart/bytecode/genericsGenerator/ConstraintsSimplifier.java

@@ -0,0 +1,92 @@
+/**
+ * 
+ */
+package de.dhbwstuttgart.bytecode.genericsGenerator;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import de.dhbwstuttgart.bytecode.TPHExtractor;
+import de.dhbwstuttgart.bytecode.constraint.TPHConstraint;
+import de.dhbwstuttgart.bytecode.simplifyRes.ConstraintsSimplierResult;
+import de.dhbwstuttgart.bytecode.simplifyRes.GenericsGeneratorResult;
+
+/**
+ * @author fayez
+ *
+ */
+public class ConstraintsSimplifier {
+	public static ConstraintsSimplierResult simplifyConstraints(TPHExtractor tphExtractor, List<GenericsGeneratorResult> genericsGeneratorResults, List<String> tphsClass) {
+		
+		List<TPHConstraint> allCons = tphExtractor.allCons;
+		List<TPHConstraint> equalCons = new ArrayList<>();
+		List<SimpleCycle> simpleCycles = findSimpleCycles(allCons);
+		
+		if(!simpleCycles.isEmpty()) {
+			handleSimpleCycles(allCons, simpleCycles);
+			equalCons.addAll(GenericsGeneratorUtility.getEqualConstraints(allCons));
+		}
+		
+		/* Step 2 */
+		List<ConstraintsWithSameLeftSide> foundCons = GenericsGeneratorUtility.findConstraintsWithLeftSameLeftSide(allCons);
+		if(!foundCons.isEmpty()) {
+			List<TPHConstraint> equalCons2 = GenericsGeneratorUtility.simplifyConstraintsWithSameLeftSide(foundCons,tphExtractor,tphsClass);
+			equalCons.addAll(equalCons2);
+		}
+		
+		List<LongCycle> longCycles = findLongCycles(allCons);
+		
+		if(!longCycles.isEmpty()) {
+			handleLongCycle(genericsGeneratorResults, allCons, longCycles);
+		}
+		/* The right hand side of equal constraint is the new name in name replacement result */
+		List<NameReplacementResult> nameReplacementResults = GenericsGeneratorUtility.createNameReplacementResultsFromEqualConstraints(equalCons);
+		ConstraintsSimplierResult result = new ConstraintsSimplierResult(genericsGeneratorResults, nameReplacementResults);
+		return result;
+	}
+
+	/**
+	 * @param genericsGeneratorResults
+	 * @param allCons
+	 * @param longCycles
+	 */
+	public static void handleLongCycle(List<GenericsGeneratorResult> genericsGeneratorResults,
+			List<TPHConstraint> allCons, List<LongCycle> longCycles) {
+		GenericsGeneratorUtility.modifyRelationForConstraintsinLongCycle(longCycles);
+		List<NameReplacementResult> nameReplacementResults = GenericsGeneratorUtility.substituteTPHSFormLongCycle(allCons, longCycles);  
+		GenericsGeneratorUtility.createResults(genericsGeneratorResults,nameReplacementResults);
+		GenericsGeneratorUtility.removeEqualConstraints(allCons);
+	}
+
+	/**
+	 * @param allCons
+	 * @return
+	 */
+	public static List<LongCycle> findLongCycles(List<TPHConstraint> allCons) {
+		/* find all long cycles */
+		CyclesFinder cyclesFinder = new CyclesFinder(allCons);
+		List<LongCycle> longCycles = cyclesFinder.findLongCycles();
+		return longCycles;
+	}
+
+	/**
+	 * @param allCons
+	 * @param simpleCycles
+	 */
+	public static void handleSimpleCycles(List<TPHConstraint> allCons, List<SimpleCycle> simpleCycles) {
+		GenericsGeneratorUtility.modifyRelation(simpleCycles);
+		GenericsGeneratorUtility.removeAllReverseConstraints(allCons,simpleCycles);
+		GenericsGeneratorUtility.substituteTPH(allCons, simpleCycles);
+	}
+
+	/**
+	 * @param allCons
+	 * @return
+	 */
+	public static List<SimpleCycle> findSimpleCycles(List<TPHConstraint> allCons) {
+		CyclesFinder cyclesFinder = new CyclesFinder(allCons);
+		/* find all simple cycles if they are exist */
+		List<SimpleCycle> simpleCycles = cyclesFinder.findSimpleCycles();
+		return simpleCycles;
+	}
+}

src/main/java/de/dhbwstuttgart/bytecode/genericsGenerator/CyclesFinder.java

@@ -4,10 +4,8 @@
 package de.dhbwstuttgart.bytecode.genericsGenerator;
 
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
-import java.util.Map;
 import java.util.Optional;
 
 import de.dhbwstuttgart.bytecode.constraint.TPHConstraint;
@@ -51,18 +49,17 @@ public class CyclesFinder {
 	public List<LongCycle> findLongCycles() {
 		List<TPHConstraint> vistedConstraints = new ArrayList<>(allCons.size());
 		List<LongCycle> longCycles = new ArrayList<>();
-		Map<String, String> tableOfConstraints = createConstraintsTable();
 		for (TPHConstraint constraint : allCons) {
 			if (!vistedConstraints.contains(constraint)) {
 				vistedConstraints.add(constraint);
-				checkConstraint(constraint, vistedConstraints, longCycles, tableOfConstraints);
+				checkConstraint(constraint, vistedConstraints, longCycles);
 			}
 		}
 		return longCycles;
 	}
 
 	private void checkConstraint(TPHConstraint constraint, List<TPHConstraint> vistedConstraints,
-			List<LongCycle> longCycles, Map<String, String> tableOfConstraints) {
+			List<LongCycle> longCycles) {
 		List<String> tphsInRelation = new LinkedList<>();
 		List<TPHConstraint> maybeCycle = new ArrayList<>();
 		maybeCycle.add(constraint);
@@ -119,14 +116,6 @@ public class CyclesFinder {
 		return null;
 	}
 
-	private Map<String, String> createConstraintsTable() {
-		Map<String, String> table = new HashMap<>();
-		for (TPHConstraint constraint : allCons) {
-			table.put(constraint.getLeft(), constraint.getRight());
-		}
-		return table;
-	}
-
 	private boolean isCycle(List<String> tphsInRelation) {
 		return tphsInRelation.get(0).equals(tphsInRelation.get(tphsInRelation.size() - 1));
 	}

src/main/java/de/dhbwstuttgart/bytecode/genericsGenerator/GenericsGenerator.java

@@ -5,19 +5,12 @@ package de.dhbwstuttgart.bytecode.genericsGenerator;
 
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Map;
-import java.util.Optional;
-import java.util.Set;
 
 import de.dhbwstuttgart.bytecode.TPHExtractor;
-import de.dhbwstuttgart.bytecode.constraint.EqualConstraint;
 import de.dhbwstuttgart.bytecode.constraint.TPHConstraint;
-import de.dhbwstuttgart.bytecode.constraint.TPHConstraint.Relation;
+import de.dhbwstuttgart.bytecode.simplifyRes.ConstraintsSimplierResult;
 import de.dhbwstuttgart.bytecode.simplifyRes.GenericsGeneratorResult;
-import de.dhbwstuttgart.bytecode.utilities.ConstraintsFinder;
-import de.dhbwstuttgart.bytecode.utilities.MethodAndTPH;
 import de.dhbwstuttgart.bytecode.utilities.MethodUtility;
-import de.dhbwstuttgart.bytecode.utilities.NameReplacer;
 import de.dhbwstuttgart.syntaxtree.Method;
 
 /**
@@ -29,33 +22,13 @@ public class GenericsGenerator {
 	public static List<GenericsGeneratorResult> generateConstraintsForMethod(Method method, TPHExtractor tphExtractor,
 			List<String> tphsClass) {
 		List<GenericsGeneratorResult> genericsGeneratorResults = new ArrayList<>();
+		
+		ConstraintsSimplierResult simplifiedConstraints = ConstraintsSimplifier.simplifyConstraints(tphExtractor, genericsGeneratorResults,tphsClass);
+		
 		List<TPHConstraint> allCons = tphExtractor.allCons;
 		String methodID = MethodUtility.createID(tphExtractor.getResolver(), method);
 		List<String> methodTPHS = GenericsGeneratorUtility.getMethodTPHS(methodID ,tphExtractor.ListOfMethodsAndTph);
 		
-		CyclesFinder cyclesFinder = new CyclesFinder(allCons);
-		/* find all simple cycles if they are exist */
-		List<SimpleCycle> simpleCycles = cyclesFinder.findSimpleCycles();
-		
-		if(!simpleCycles.isEmpty()) {
-			GenericsGeneratorUtility.modifyRelation(simpleCycles);
-			GenericsGeneratorUtility.removeAllReverseConstraints(allCons,simpleCycles);
-			GenericsGeneratorUtility.substituteTPH(allCons, simpleCycles);
-			GenericsGeneratorUtility.removeEqualConstraints(allCons);
-		}
-		
-		/* Step 2 */
-		List<ConstraintsWithSameLeftSide> foundCons = GenericsGeneratorUtility.findConstraintsWithLeftSameLeftSide(allCons);
-		GenericsGeneratorUtility.simplifyConstraintsWithSameLeftSide(foundCons,allCons,methodTPHS);
-		
-		/* find all long cycles */
-		List<LongCycle> longCycles = cyclesFinder.findLongCycles();
-		
-		if(!longCycles.isEmpty()) {
-			GenericsGeneratorUtility.modifyRelationForConstraintsinLongCycle(longCycles);
-			List<NameReplacementResult> nameReplacementResults = GenericsGeneratorUtility.substituteTPHSFormLongCycle(allCons, longCycles);  
-			GenericsGeneratorUtility.createResults(genericsGeneratorResults,nameReplacementResults);
-		}
 		return null;
 	}
 	

src/main/java/de/dhbwstuttgart/bytecode/genericsGenerator/GenericsGeneratorUtility.java

@@ -13,7 +13,9 @@ import java.util.stream.Collectors;
 
 import org.objectweb.asm.Type;
 
+import de.dhbwstuttgart.bytecode.TPHExtractor;
 import de.dhbwstuttgart.bytecode.constraint.EqualConstraint;
+import de.dhbwstuttgart.bytecode.constraint.ExtendsConstraint;
 import de.dhbwstuttgart.bytecode.constraint.TPHConstraint;
 import de.dhbwstuttgart.bytecode.constraint.TPHConstraint.Relation;
 import de.dhbwstuttgart.bytecode.simplifyRes.GenericsGeneratorResult;
@@ -60,7 +62,9 @@ public class GenericsGeneratorUtility {
 	 * @param newName The new name
 	 */
 	public static void substituteTPH(List<TPHConstraint> allCons, String oldName, String newName) {
-		allCons.forEach(c->{
+		allCons.stream()
+		.filter(c->c.getRel()==Relation.EXTENDS)
+		.forEach(c->{
 			if(c.getLeft().equals(oldName))
 				c.setLeft(newName);
 			if(c.getRight().equals(oldName))
@@ -114,10 +118,34 @@ public class GenericsGeneratorUtility {
 		
 	}
 	
+	public static List<TPHConstraint> simplifyConstraintsWithSameLeftSide(List<ConstraintsWithSameLeftSide> consWithSameLeftSide,
+			TPHExtractor tphExtractor, List<String> tphsClass) {
+		List<TPHConstraint> eqCons = new ArrayList<>();
+		List<TPHConstraint> allCons = tphExtractor.allCons;
+		
+		for (ConstraintsWithSameLeftSide list : consWithSameLeftSide) {
+			NameReplacementResult replRes = modifyNames(allCons, list, tphExtractor.ListOfMethodsAndTph,tphsClass);
+			createEqualConstraintsForNames(replRes.getName(), replRes.getOldNames(),eqCons);
+			
+			for (TPHConstraint c : allCons) {
+				if (c.getRel() == Relation.EQUAL && replRes.getName().equals(c.getRight())) {
+					eqCons.add(c);
+				}
+			}
+			updateEqualCons(replRes, eqCons);
+
+			TPHConstraint c = list.getConstraints().get(0);
+			allCons.removeAll(list.getConstraints());
+			allCons.add(c);
+		}
+		return eqCons;
+		
+	}
+
 	private static void createEqualConstraintsForNames(String name, List<String> equalNames, List<TPHConstraint> eqCons) {
 		// create an equal constraint for each value in repres
 		for (String eName : equalNames) {
-			EqualConstraint ec = new EqualConstraint(eName, name, Relation.EQUAL);
+			EqualConstraint ec = new EqualConstraint(eName, name);
 			eqCons.add(ec);
 		}
 	}
@@ -138,6 +166,15 @@ public class GenericsGeneratorUtility {
 		return replRes;
 	}
 	
+	public static NameReplacementResult modifyNames(List<TPHConstraint> allCons, ConstraintsWithSameLeftSide list, List<MethodAndTPH> methodAndTPHs, List<String> tphsClass) {
+		// generate a new name and replace the right hand side for each constraint
+		// in list with the new name
+		NameReplacer replacer = new NameReplacer(list.getConstraints(), allCons, methodAndTPHs, tphsClass);
+		// new name -> [all old names]
+		NameReplacementResult replRes = replacer.replaceNames();
+		return replRes;
+	}
+	
 	public static void updateEqualCons(NameReplacementResult nameReplacementResult, List<TPHConstraint> eqCons) {
 		List<String> oldNames = nameReplacementResult.getOldNames();
 		String newName = nameReplacementResult.getName();
@@ -190,7 +227,7 @@ public class GenericsGeneratorUtility {
 			List<NameReplacementResult> nameReplacementResults) {
 		nameReplacementResults.forEach(n->{
 			Set<String> equals = new HashSet<>(n.getOldNames());
-			TPHConstraint cons = new EqualConstraint(n.getName(), Type.getInternalName(Object.class), Relation.EXTENDS);
+			TPHConstraint cons = new ExtendsConstraint(n.getName(), Type.getInternalName(Object.class));
 			GenericsGeneratorResult ggRes = new GenericsGeneratorResult(cons, equals);
 			genericsGeneratorResults.add(ggRes);
 		});
@@ -204,4 +241,31 @@ public class GenericsGeneratorUtility {
 	public static List<TPHConstraint> getEqualConstraints(List<TPHConstraint> allCons) {
 		return allCons.stream().filter(c->c.getRel()==Relation.EQUAL).collect(Collectors.toList());
 	}
+
+	public static List<NameReplacementResult> createNameReplacementResultsFromEqualConstraints(
+			List<TPHConstraint> equalCons) {
+		List<NameReplacementResult> nameReplacementResults = new ArrayList<>();
+		equalCons.forEach(c->{
+			if(isInNameReplacementResults(nameReplacementResults,c.getRight())) {
+				getNameReplacementByName(nameReplacementResults,c.getRight()).getOldNames().add(c.getLeft());
+			} else {
+				List<String> oldNames = new ArrayList<>();
+				oldNames.add(c.getLeft());
+				NameReplacementResult nrRes = new NameReplacementResult(c.getRight(), oldNames);
+				nameReplacementResults.add(nrRes);
+			}
+		});
+		return nameReplacementResults;
+	}
+	
+	private static NameReplacementResult getNameReplacementByName(List<NameReplacementResult> nameReplacementResults,
+			String name) {
+		return nameReplacementResults.stream().filter(n->n.getName().equals(name)).findFirst().get();
+	}
+
+	public static boolean isInNameReplacementResults(List<NameReplacementResult> nameReplacementResults,String name){
+		if(nameReplacementResults.isEmpty())
+			return false;
+		return nameReplacementResults.stream().map(r->r.getName()).filter(n->name.equals(n)).findFirst().isPresent();
+	}
 }

src/main/java/de/dhbwstuttgart/bytecode/signature/Signature.java

@@ -258,7 +258,7 @@ public class Signature {
 			if(resolved instanceof TypePlaceholder) {
 				//resType.getAdditionalGenerics().forEach(ag ->{
 				resultSet.genIns.forEach(ag ->{
-					TPHConstraint constr = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName(), Relation.EXTENDS);
+					TPHConstraint constr = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName());
 					if(!contains(res,constr)) {
 						res.add(constr);
 					}
@@ -270,7 +270,7 @@ public class Signature {
 				if(resType2.resolvedType instanceof TypePlaceholder) {
 					//resType2.getAdditionalGenerics().forEach(ag ->{
 					resultSet.genIns.forEach(ag ->{
-						TPHConstraint constr = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName(), Relation.EXTENDS);
+						TPHConstraint constr = new ExtendsConstraint(ag.getLeft().getName(), ag.getRight().getName());
 						if(!contains(res,constr)) {
 							res.add(constr);
 						}

src/main/java/de/dhbwstuttgart/bytecode/simplifyRes/ConstraintsSimplierResult.java

@@ -0,0 +1,53 @@
+/**
+ * 
+ */
+package de.dhbwstuttgart.bytecode.simplifyRes;
+
+import java.util.List;
+
+import de.dhbwstuttgart.bytecode.constraint.TPHConstraint;
+import de.dhbwstuttgart.bytecode.genericsGenerator.NameReplacementResult;
+
+/**
+ * This class represents the result of the constraints simplifier.
+ * 
+ * @author fayez
+ *
+ */
+public class ConstraintsSimplierResult {
+	private List<GenericsGeneratorResult> genericsGenResults;
+	private List<NameReplacementResult> nameReplacementResults;
+	/**
+	 * @param genericsGenResults
+	 */
+	public ConstraintsSimplierResult(List<GenericsGeneratorResult> genericsGenResults, 
+			List<NameReplacementResult> nameReplacementResults) {
+		this.genericsGenResults = genericsGenResults;
+		this.setNameReplacementResults(nameReplacementResults);
+	}
+	/**
+	 * @return the genericsGenResults
+	 */
+	public List<GenericsGeneratorResult> getGenericsGenResults() {
+		return genericsGenResults;
+	}
+	/**
+	 * @param genericsGenResults the genericsGenResults to set
+	 */
+	public void setGenericsGenResults(List<GenericsGeneratorResult> genericsGenResults) {
+		this.genericsGenResults = genericsGenResults;
+	}
+	/**
+	 * @return the nameReplacementResults
+	 */
+	public List<NameReplacementResult> getNameReplacementResults() {
+		return nameReplacementResults;
+	}
+	/**
+	 * @param nameReplacementResults the nameReplacementResults to set
+	 */
+	public void setNameReplacementResults(List<NameReplacementResult> nameReplacementResults) {
+		this.nameReplacementResults = nameReplacementResults;
+	}
+	
+}

src/main/java/de/dhbwstuttgart/bytecode/utilities/NameReplacer.java

@@ -10,8 +10,11 @@ import de.dhbwstuttgart.bytecode.genericsGenerator.NameReplacementResult;
 import de.dhbwstuttgart.syntaxtree.factory.NameGenerator;
 
 public class NameReplacer {
+	//TODO rename
 	private List<TPHConstraint> constraints;
 	private List<TPHConstraint> allConstraints;
+	private List<MethodAndTPH> methodAndTPHs;
+	// TODO rename into tphClass
 	private List<String> tphs;
 	private List<String> localTphs;
 	
@@ -30,11 +33,44 @@ public class NameReplacer {
 		this.tphs = tphs;
 	}
 	
+	public NameReplacer(List<TPHConstraint> constraints, List<TPHConstraint> allConstraints) {
+		this.constraints = constraints;
+		this.allConstraints = allConstraints;
+	}
+
+	public NameReplacer(List<TPHConstraint> constraints, List<TPHConstraint> allConstraints, List<MethodAndTPH> methodAndTPHs,
+			List<String> tphsClass) {
+		this.constraints = constraints;
+		this.allConstraints = allConstraints;
+		this.methodAndTPHs = methodAndTPHs;
+		this.tphs = tphsClass;
+	}
+
 	public NameReplacementResult replaceNames() {
 		String newName = NameGenerator.makeNewName();
 		List<String> names = new ArrayList<>();
 		substituteRightSidesWithNewName(newName, names);
 		
+		substituteNamesInAllConstraints(newName, names);
+		methodAndTPHs.stream().map(m->m.getTphs()).forEach(tphsMethod->{
+			if(tphsMethod.removeAll(names))
+				tphsMethod.add(newName);
+		});
+		
+		
+		if(tphs.removeAll(names))
+			tphs.add(newName);
+		
+		NameReplacementResult res = new NameReplacementResult(newName, names);
+		
+		return res;
+	}
+	
+	public NameReplacementResult replaceNamesLocal() {
+		String newName = NameGenerator.makeNewName();
+		List<String> names = new ArrayList<>();
+		substituteRightSidesWithNewName(newName, names);
+		
 		substituteNamesInAllConstraints(newName, names);
 		
 		tphs.removeAll(names);

src/main/java/de/dhbwstuttgart/bytecode/utilities/Simplify.java

@@ -162,8 +162,7 @@ public class Simplify {
 						eq.add(t);
 					}
 					// generate a new constraint (left < Object)
-					TPHConstraint constraint = new ExtendsConstraint(left, Type.getInternalName(Object.class),
+					TPHConstraint constraint = new ExtendsConstraint(left, Type.getInternalName(Object.class));
-							Relation.EXTENDS);
 					// put the generated constraint and its equal set into result set
 					result.put(constraint, eq);
 					constraints.clear();
@@ -217,8 +216,7 @@ public class Simplify {
 			if (!result.containsKey(cons)) {
 				result.put(cons, null);
 				if (!cons.getRight().equals(Type.getInternalName(Object.class)))
-					result.put(new ExtendsConstraint(cons.getRight(), Type.getInternalName(Object.class),
+					result.put(new ExtendsConstraint(cons.getRight(), Type.getInternalName(Object.class)), null);
-							Relation.EXTENDS), null);
 			}
 
 			return result;
@@ -248,7 +246,7 @@ public class Simplify {
 			// create an equal constraint for each value in repres
 			String key = replRes.getName();
 			for (String val : replRes.getOldNames()) {
-				EqualConstraint ec = new EqualConstraint(val, key, Relation.EQUAL);
+				EqualConstraint ec = new EqualConstraint(val, key);
 				eqCons.add(ec);
 			}
 			for (TPHConstraint c : allCons) {
@@ -391,18 +389,18 @@ public class Simplify {
 			if (!containTPH(methodTphs, superTphRes)) {
 				HashSet<String> equals = getEqualsTphsFromEqualCons(eqCons, superTphRes);
 				if (tphsClass.contains(superTphRes)/*classTPHSContainsTPH(tphsClass, superTphRes)*/) {
-					result.put(new ExtendsConstraint(subTphRes, superTphRes, Relation.EXTENDS), equals);
+					result.put(new ExtendsConstraint(subTphRes, superTphRes), equals);
 				} else {
-					result.put(new ExtendsConstraint(subTphRes, Type.getInternalName(Object.class), Relation.EXTENDS),
+					result.put(new ExtendsConstraint(subTphRes, Type.getInternalName(Object.class)),
 							equals);
 				}
 
 			} else {
 				HashSet<String> equals = getEqualsTphsFromEqualCons(eqCons, subTphRes);
-				result.put(new ExtendsConstraint(subTphRes, superTphRes, Relation.EXTENDS), equals);
+				result.put(new ExtendsConstraint(subTphRes, superTphRes), equals);
 				if (!isTPHInConstraint(result, superTphRes) && !isTphInEqualSet(result, superTphRes)) {
 					HashSet<String> equals2 = getEqualsTphsFromEqualCons(eqCons, superTphRes);
-					result.put(new ExtendsConstraint(superTphRes, Type.getInternalName(Object.class), Relation.EXTENDS),
+					result.put(new ExtendsConstraint(superTphRes, Type.getInternalName(Object.class)),
 							equals2);
 				}
 			}
@@ -412,7 +410,7 @@ public class Simplify {
 		for (String tph : localTphs) {
 			if (!isTPHInConstraint(result, tph) && !isTphInEqualSet(result, tph)) {
 				HashSet<String> equals = getEqualsTphsFromEqualCons(eqCons, tph);
-				result.put(new ExtendsConstraint(tph, Type.getInternalName(Object.class), Relation.EXTENDS), equals);
+				result.put(new ExtendsConstraint(tph, Type.getInternalName(Object.class)), equals);
 			}
 		}
 
@@ -583,8 +581,7 @@ public class Simplify {
 						eq.add(t);
 					}
 					// generate a new constraint (left < Object)
-					TPHConstraint constraint = new ExtendsConstraint(left, Type.getInternalName(Object.class),
+					TPHConstraint constraint = new ExtendsConstraint(left, Type.getInternalName(Object.class));
-							Relation.EXTENDS);
 					// put the generated constraint and its equal set into result set
 					result.put(constraint, eq);
 					constraints.clear();
@@ -619,7 +616,7 @@ public class Simplify {
 			TPHConstraint cons = allCons.get(0);
 			if (!result.containsKey(cons)) {
 				result.put(cons, null);
-				result.put(new ExtendsConstraint(cons.getRight(), Type.getInternalName(Object.class), Relation.EXTENDS),
+				result.put(new ExtendsConstraint(cons.getRight(), Type.getInternalName(Object.class)),
 						null);
 			}
 
@@ -699,7 +696,7 @@ public class Simplify {
 			subTphRes = tphInRel.getFirst();
 
 			HashSet<String> equals = getEqualsTphsFromEqualCons(eqCons, superTphRes);
-			result.put(new ExtendsConstraint(subTphRes, superTphRes, Relation.EXTENDS), equals);
+			result.put(new ExtendsConstraint(subTphRes, superTphRes), equals);
 
 		}
 
@@ -754,7 +751,7 @@ public class Simplify {
 		substituteTPH(allCons, toSubs, tph);
 		if (subAndSuper.containsKey(toSubs) && subAndSuper.containsKey(tph)) {
 			toSubs = subAndSuper.remove(toSubs);
-			EqualConstraint eq = new EqualConstraint(subAndSuper.get(tph), toSubs, Relation.EQUAL);
+			EqualConstraint eq = new EqualConstraint(subAndSuper.get(tph), toSubs);
 			eqCons.add(eq);
 			substituteInMap(subAndSuper, allCons, eqCons, toSubs, subAndSuper.get(tph));
 		} else if (subAndSuper.containsKey(toSubs) && !subAndSuper.containsKey(tph)) {
@@ -947,11 +944,11 @@ public class Simplify {
 				i++;
 			}
 			if (superTphRes.equals(Type.getInternalName(Object.class))) {
-				result.put(new ExtendsConstraint(subTphRes, Type.getInternalName(Object.class), Relation.EXTENDS),
+				result.put(new ExtendsConstraint(subTphRes, Type.getInternalName(Object.class)),
 						null);
 			} else {
-				result.put(new ExtendsConstraint(subTphRes, superTphRes, Relation.EXTENDS), null);
+				result.put(new ExtendsConstraint(subTphRes, superTphRes), null);
-				result.put(new ExtendsConstraint(superTphRes, Type.getInternalName(Object.class), Relation.EXTENDS),
+				result.put(new ExtendsConstraint(superTphRes, Type.getInternalName(Object.class)),
 						null);
 			}
 
@@ -1023,7 +1020,7 @@ public class Simplify {
 				return c;
 		}
 
-		return new ExtendsConstraint(toFind.getRight(), Type.getInternalName(Object.class), Relation.EXTENDS);
+		return new ExtendsConstraint(toFind.getRight(), Type.getInternalName(Object.class));
 	}
 
 	private static TPHConstraint getKeyConstraint(Map<TPHConstraint, Set<String>> result,
@@ -1034,7 +1031,7 @@ public class Simplify {
 				return c;
 		}
 
-		return new ExtendsConstraint(toFind.getRight(), Type.getInternalName(Object.class), Relation.EXTENDS);
+		return new ExtendsConstraint(toFind.getRight(), Type.getInternalName(Object.class));
 	}
 
 	private static Set<String> getEqualsTPHs(Map<TPHConstraint, Set<String>> result, TPHConstraint toFind) {