add Exception for null equipement

Signed-off-by: Leclerc Clement <[email protected]>

ucte/ucte-converter/src/main/java/com/powsybl/ucte/converter/AbstractNamingStrategy.java

@@ -7,6 +7,7 @@
  */
 package com.powsybl.ucte.converter;
 
+import com.powsybl.commons.PowsyblException;
 import com.powsybl.iidm.network.*;
 import com.powsybl.ucte.converter.util.UcteConverterConstants;
 import com.powsybl.ucte.network.UcteElementId;
@@ -36,6 +37,9 @@ public UcteNodeCode getUcteNodeCode(String id) {
 
     @Override
     public UcteNodeCode getUcteNodeCode(Bus bus) {
+        if(bus == null) {
+            throw  new PowsyblException("the bus is null");
+        }
         return getUcteNodeCode(bus.getId());
     }
 
@@ -55,16 +59,25 @@ public UcteElementId getUcteElementId(String id) {
 
     @Override
     public UcteElementId getUcteElementId(Switch sw) {
+        if(sw == null) {
+            throw  new PowsyblException("the bus is null");
+        }
         return getUcteElementId(sw.getId());
     }
 
     @Override
     public UcteElementId getUcteElementId(Branch branch) {
+        if(branch == null) {
+            throw  new PowsyblException("the bus is null");
+        }
         return getUcteElementId(branch.getId());
     }
 
     @Override
     public UcteElementId getUcteElementId(DanglingLine danglingLine) {
+        if(danglingLine == null) {
+            throw  new PowsyblException("the bus is null");
+        }
         return getUcteElementId(danglingLine.getId());
     }
 }