code: private void setAttrValue(final AttrName _attrName,
                                final String _value)
      {
          synchronized (this.attrValues) {
              this.attrValues.put(_attrName, _value);
          }
      }
docs: The method sets the attribute values in the cache for given attribute
  name to given new attribute value.
  
  @param _attrName name of attribute to set
  @param _value new value to set
  @see #attrValues