code: public boolean removeSearchFieldMapping(CmsLuceneField field, CmsSearchFieldMapping mapping)
      throws CmsIllegalStateException {
  
          if (field.getMappings().size() < 2) {
              throw new CmsIllegalStateException(
                  Messages.get().container(
                      Messages.ERR_FIELD_MAPPING_DELETE_2,
                      mapping.getType().toString(),
                      field.getName()));
          } else {
  
              if (LOG.isInfoEnabled()) {
                  LOG.info(
                      Messages.get().getBundle().key(
                          Messages.LOG_REMOVE_FIELD_MAPPING_INDEX_2,
                          mapping.toString(),
                          field.getName()));
              }
              return field.getMappings().remove(mapping);
          }
      }
docs: Removes a search field mapping from the given field.<p>
  
  @param field the field
  @param mapping mapping to remove from the field
  
  @return true if remove was successful, false if preconditions for removal are ok but the given
  mapping was unknown.
  
  @throws CmsIllegalStateException if the given mapping is the last mapping inside the given field.