Implement state transition methods

Now you can code the implementations of your specialized state transition methods:

Figure 1. Implementing state transition methods

/**
   * {@inheritDoc}
   */
  public void close(Date endDate, int versionNo)
    throws InformationalException {
    // store the date of closure
    setEndDate(endDate);

    // transition to "closed"
    transitionTo(CLOSED, versionNo);
  }

  /**
   * {@inheritDoc}
   */
  public void resume(int versionNo) throws InformationalException {
    // blank the suspension reason
    setSuspensionReason(null);

    // transition to "open"
    transitionTo(OPEN, versionNo);
  }

  /**
   * {@inheritDoc}
   */
  public void suspend(String reason, int versionNo)
      throws InformationalException {
    // store the suspension reason
    setSuspensionReason(reason);

    // transition to "suspended"
    transitionTo(SUSPENDED, versionNo);
  }

These methods are publicly visible and callable through the entity's interface. Note that in the figure above, additional setter methods (setEndDate and setSuspensionReason) are assumed.