code: protected void setRelatedLock(CmsLock relatedLock) {
  
          if (this == NULL_LOCK) {
              throw new RuntimeException("null lock");
          }
          if ((relatedLock == null) || relatedLock.isUnlocked()) {
              m_relatedLock = null;
          } else {
              m_relatedLock = relatedLock;
              m_relatedLock.m_relatedLock = this;
          }
      }
docs: Sets the related Lock.<p>
  
  @param relatedLock the related Lock to set