public void validate(Form<?> form) {
   String commonName = this.commonNameTextField.getInput();
   if (commonName != null) {
     commonName = commonName.toLowerCase();
     if (commonNameTextField.getModelObject() != null
         && commonName.equals(commonNameTextField.getModelObject().toLowerCase())) return;
     for (TransferCapability transferCapability :
         this.applicationEntity.getTransferCapabilities()) {
       if (transferCapability.getCommonName() != null
           && commonName.equals(transferCapability.getCommonName().toLowerCase()))
         commonNameTextField.error(
             new StringResourceModel("TransferCapabilityValidator.commonName.invalid", form, null)
                 .getObject());
     }
   }
   String sopClass = this.sopClassTextField.getInput();
   String role = this.roleDropDown.getInput().equals("0") ? "SCP" : "SCU";
   if (sopClass.equals(sopClassTextField.getModelObject())
       && role.equals(roleDropDown.getModelObject().name())) return;
   for (TransferCapability transferCapability : this.applicationEntity.getTransferCapabilities()) {
     if (sopClass.equals(transferCapability.getSopClass())
         && role.equals(transferCapability.getRole().name()))
       sopClassTextField.error(
           new StringResourceModel("TransferCapabilityValidator.sopClass-role.invalid", form, null)
               .getObject());
   }
 }