diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/Assignment.java b/AlgebraicDataflowArchitectureModel/src/code/ast/Assignment.java
index a7a2fc9..9145f61 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/Assignment.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/Assignment.java
@@ -14,6 +14,11 @@
 		this.right = right;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new Assignment(left.replace(variable, expression), right.replace(variable, expression));
+	}
+	
 	public Expression getLeft() {
 		return left;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/ClassInstanceCreation.java b/AlgebraicDataflowArchitectureModel/src/code/ast/ClassInstanceCreation.java
index fe20607..fd6d138 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/ClassInstanceCreation.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/ClassInstanceCreation.java
@@ -1,5 +1,6 @@
 package code.ast;
 
+import java.util.ArrayList;
 import java.util.List;
 
 public class ClassInstanceCreation extends Expression {
@@ -16,6 +17,17 @@
 		this.arguments = arguments;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		List<Expression> replacedExpressions = new ArrayList<>();
+		
+		for (Expression argument : arguments) {
+			replacedExpressions.add(argument.replace(variable, expression));
+		}
+		
+		return new ClassInstanceCreation(type, replacedExpressions);
+	}
+	
 	public Type getType() {
 		return type;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/Constant.java b/AlgebraicDataflowArchitectureModel/src/code/ast/Constant.java
index f15c136..296f050 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/Constant.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/Constant.java
@@ -12,6 +12,11 @@
 		this.value = value;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return this;
+	}
+	
 	public String getValue() {
 		return value;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/FieldAccess.java b/AlgebraicDataflowArchitectureModel/src/code/ast/FieldAccess.java
index bfae25d..dacc3e7 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/FieldAccess.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/FieldAccess.java
@@ -19,6 +19,11 @@
 		this.fieldName = fieldName;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new FieldAccess(expression.replace(variable, expression), fieldName);
+	}
+	
 	public Expression getExpression() {
 		return expression;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/InfixExpression.java b/AlgebraicDataflowArchitectureModel/src/code/ast/InfixExpression.java
index 8aa90be..adf0fba 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/InfixExpression.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/InfixExpression.java
@@ -19,6 +19,11 @@
 		this.rightOperand = rightOperand;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new InfixExpression(operator, leftOperand.replace(variable, expression), rightOperand.replace(variable, expression));
+	}
+	
 	public Symbol getOperator() {
 		return this.operator;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/MethodInvocation.java b/AlgebraicDataflowArchitectureModel/src/code/ast/MethodInvocation.java
index 94c90e1..5d8a848 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/MethodInvocation.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/MethodInvocation.java
@@ -1,5 +1,6 @@
 package code.ast;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -39,6 +40,21 @@
 		this.arguments = arguments;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		List<Expression> replacedExpressions = new ArrayList<>();
+		
+		for (Expression argument : arguments) {
+			replacedExpressions.add(argument.replace(variable, expression));
+		}
+		
+		if (receiver == null) {
+			return new MethodInvocation(null, methodName, replacedExpressions);
+		}
+		
+		return new MethodInvocation(receiver.replace(variable, expression), methodName, replacedExpressions);
+	}
+	
 	public Expression getReceiver() {
 		return receiver;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/ParenthesizedExpression.java b/AlgebraicDataflowArchitectureModel/src/code/ast/ParenthesizedExpression.java
index a7b50cb..4fe659e 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/ParenthesizedExpression.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/ParenthesizedExpression.java
@@ -13,6 +13,11 @@
 		this.expression = expression;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new ParenthesizedExpression(this.expression.replace(variable, expression));
+	}
+	
 	public Expression getExpression() {
 		return expression;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/PostfixExpression.java b/AlgebraicDataflowArchitectureModel/src/code/ast/PostfixExpression.java
index bc520ac..2793c32 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/PostfixExpression.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/PostfixExpression.java
@@ -30,6 +30,11 @@
 		this.operator = operator;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new PostfixExpression(operand.replace(variable, expression), operator);
+	}
+	
 	public Expression getOperand() {
 		return operand;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/PrefixExpression.java b/AlgebraicDataflowArchitectureModel/src/code/ast/PrefixExpression.java
index 2e854b7..debce52 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/PrefixExpression.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/PrefixExpression.java
@@ -30,6 +30,11 @@
 		this.operator = operator;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return new PrefixExpression(operand.replace(variable, expression), operator);
+	}
+	
 	public Expression getOperand() {
 		return operand;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/SuperMethodInvocation.java b/AlgebraicDataflowArchitectureModel/src/code/ast/SuperMethodInvocation.java
index e7e3573..39380b2 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/SuperMethodInvocation.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/SuperMethodInvocation.java
@@ -1,5 +1,6 @@
 package code.ast;
 
+import java.util.ArrayList;
 import java.util.List;
 
 /**
@@ -21,6 +22,17 @@
 		this.arguments = arguments;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		List<Expression> replacedExpressions = new ArrayList<>();
+		
+		for (Expression argument : arguments) {
+			replacedExpressions.add(argument.replace(variable, expression));
+		}
+		
+		return new SuperMethodInvocation(methodName, replacedExpressions);
+	}
+	
 	public String getMethodName() {
 		return methodName;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/ThisExpression.java b/AlgebraicDataflowArchitectureModel/src/code/ast/ThisExpression.java
index 5ef621e..05d456d 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/ThisExpression.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/ThisExpression.java
@@ -2,6 +2,11 @@
 
 public class ThisExpression extends Expression {
 	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return this;
+	}
+	
+	@Override
 	public String toString() {
 		return "this";
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/TypeLiteral.java b/AlgebraicDataflowArchitectureModel/src/code/ast/TypeLiteral.java
index 4163b7d..69ebe3b 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/TypeLiteral.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/TypeLiteral.java
@@ -12,6 +12,11 @@
 		this.type = type;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		return this;
+	}
+	
 	public Type getType() {
 		return type;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/code/ast/Variable.java b/AlgebraicDataflowArchitectureModel/src/code/ast/Variable.java
index 6d3dc00..baf9388 100644
--- a/AlgebraicDataflowArchitectureModel/src/code/ast/Variable.java
+++ b/AlgebraicDataflowArchitectureModel/src/code/ast/Variable.java
@@ -12,6 +12,14 @@
 		this.name = name;
 	}
 	
+	@Override
+	public Expression replace(Variable variable, Expression expression) {
+		if (this == variable) {
+			return expression;
+		}
+		return this;
+	}
+	
 	public String getName() {
 		return name;
 	}
diff --git a/AlgebraicDataflowArchitectureModel/src/tests/ASTTest.java b/AlgebraicDataflowArchitectureModel/src/tests/ASTTest.java
index c29320f..38d5144 100644
--- a/AlgebraicDataflowArchitectureModel/src/tests/ASTTest.java
+++ b/AlgebraicDataflowArchitectureModel/src/tests/ASTTest.java
@@ -1,6 +1,7 @@
 package tests;
 
 import code.ast.*;
+import models.algebra.Type;
 import models.dataConstraintModel.DataConstraintModel;
 
 import java.util.Arrays;
@@ -14,7 +15,7 @@
 
         VariableDeclarationStatement varStmt = new VariableDeclarationStatement();
         varStmt.setModifiers(List.of(new PlainStatement("private")));
-        varStmt.setType(new PrimitiveType(new SimpleName("int")));
+        varStmt.setType(new PrimitiveType(DataConstraintModel.typeInt));
         varStmt.setFragments(List.of(
                 new VariableDeclaration(DataConstraintModel.typeInt, "x"),
                 new VariableDeclaration(DataConstraintModel.typeInt, "sum")