TSK-664: added hash and equals methods to KeyDomain.

lib/taskana-core/src/main/java/pro/taskana/KeyDomain.java

@@ -42,4 +42,35 @@ public class KeyDomain {
         return builder.toString();
     }
 
+    @Override
+    public int hashCode() {
+        final int prime = 31;
+        int result = 1;
+        result = prime * result + ((domain == null) ? 0 : domain.hashCode());
+        result = prime * result + ((key == null) ? 0 : key.hashCode());
+        return result;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj)
+            return true;
+        if (obj == null)
+            return false;
+        if (getClass() != obj.getClass())
+            return false;
+        KeyDomain other = (KeyDomain) obj;
+        if (domain == null) {
+            if (other.domain != null)
+                return false;
+        } else if (!domain.equals(other.domain))
+            return false;
+        if (key == null) {
+            if (other.key != null)
+                return false;
+        } else if (!key.equals(other.key))
+            return false;
+        return true;
+    }
+
 }