Skill.java

abstract class Skill {
  
  public boolean itemOnItem(Player p, int itemId, int otherItem) {
    if(!prepared(p))
      return false;
    
    return handleItemOnItem(p, itemId, otherItem);
  }
  
  public boolean objectClick(Player p, int objectId, int clickIndex) {
    if(!prepared(p))
      return false;
    
    return handleObjectClick(p, objectId, clickIndex);
  }
  
  public boolean prepared(Player p) {
    if(playerBusy(p)) {
      p,sendMessage("Please stop what you are doing first.");
      return false;
    }
    
    if(!hasLevelRequirements(p)) {
      p.sendMessage("You do not have the level requirements for this.");
      return false;
    }
    
    if(!hasItemRequirements(p)) {
      p.sendMessage("You do not have the items required for this.");
      return false;
    }
    
    return true;
  }
  
  private boolean playerBusy(Player p) {
    return ...;
  }
  
  protected abstract boolean hasLevelRequirement(Player p);
  protected abstract boolean hasItemRequirements(Player p);
  protected boolean handleItemOnItem(Player p, int itemId, int otherItem) { return false; }
  protected boolean handleObjectClick(Player p, int objectId, int clickIndex) { rerurn false; }
}