Enhancing VoltageLevel with hashCode method.

Author: staudtMarius

src/main/java/edu/ie3/datamodel/models/voltagelevels/CommonVoltageLevel.java

@@ -7,10 +7,7 @@
 
 import edu.ie3.datamodel.exceptions.VoltageLevelException;
 import edu.ie3.util.interval.RightOpenInterval;
-import java.util.Collections;
-import java.util.Set;
-import java.util.SortedSet;
-import java.util.TreeSet;
+import java.util.*;
 import javax.measure.quantity.ElectricPotential;
 import tech.units.indriya.ComparableQuantity;
 
@@ -88,6 +85,11 @@ public boolean equals(Object o) {
     return this.voltageRange.equals(that.voltageRange);
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(super.hashCode(), synonymousIds, voltageRange);
+  }
+
   @Override
   public String toString() {
     return "CommonVoltageLevel{"

src/main/java/edu/ie3/datamodel/models/voltagelevels/VoltageLevel.java

@@ -6,6 +6,7 @@
 package edu.ie3.datamodel.models.voltagelevels;
 
 import java.io.Serializable;
+import java.util.Objects;
 import javax.measure.quantity.ElectricPotential;
 import tech.units.indriya.ComparableQuantity;
 
@@ -56,6 +57,11 @@ public boolean equals(Object o) {
     return this.nominalVoltage.isEquivalentTo(that.nominalVoltage);
   }
 
+  @Override
+  public int hashCode() {
+    return Objects.hash(id, nominalVoltage);
+  }
+
   @Override
   public String toString() {
     return "VoltageLevel{" + "id='" + id + '\'' + ", nominalVoltage=" + nominalVoltage + '}';