code: public boolean expireId(final String identifier, final long expirationTime) {
  
  		if (identifier == null) {
  			log.error("Unable to expire a null Identifier value.");
  			return false;
  		}
  
  		if (this.originString == null) {
  			log.error("Origin has not been set.  Cannot expire Ids without a valid origin.");
  			return false;
  		}
  		ExpireIdentifierMessage message = new ExpireIdentifierMessage();
  		message.setOrigin(this.originString);
  		message.setId(identifier);
  		message.setExpirationTime(expirationTime);
  
  		this.session.write(message);
  		log.debug("Sent {}", message);
  
  		return true;
  	}
docs: Expires all Attributes for an Identifier in the world model.
  
  @param identifier
  the identifier to expire.
  @param expirationTime
  the expiration timestamp.
  @return {@code true} if the message is sent successfully, else
  {@code false}.