Example 8.20 SkillSet Dependent Object Implements DirtyMarker 
Interface

public class SkillSetVO implements DirtyMarker, 
  java.io.Serializable {
  private String skillName;
  private String expertiseLevel;
  private String info;
  ...

  // dirty flag
  private boolean dirty = false;

  // new flag
  private boolean isnew = true;

  // deleted flag
  private boolean deleted = false;

  public SkillSetVO(...) {
    // initialization
    ...
    // is new VO
    setNew();
  }

  // get, set and other methods for SkillSet
  // all set methods and modifier methods
  // must call setDirty()
  public setSkillName(String newSkillName) {
    skillName = newSkillName;
    setDirty();
  }
  ...

  // DirtyMarker methods
  // used for modified value objects only
  public void setDirty() {
    dirty = true;
  }
  public void resetDirty() {
    dirty = false;
  }
  public boolean isDirty() {
    return dirty;
  }

  // used for new value objects only
  public void setNew() {
    isnew = true;
  }
  public void resetNew() {
    isnew = false;
  }
  public boolean isNew() {
    return isnew;
  }

  // used for deleted objects only
  public void setDeleted() {
    deleted = true;
  }
  public boolean isDeleted() {
    return deleted;
  }
  public void resetDeleted() {
    deleted = false;
  }

}