编辑“︁Refactoring Database Access in Marauroa”︁（章节）

== Porting of JMaPacman ==

The following diff shows the complete list of changes that were required to port JMaPacman. I think it may help you to get a feeling on how to adjust your own code.
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<source lang="java">
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  public class MaPacmanRPRuleProcessor implements IRPRuleProcessor
    {
    public AccountResult createAccount(String username, String password, String email) {
 
 -    IDatabase database = DatabaseFactory.getDatabase();
 +    '''TransactionPool transactionPool = TransactionPool.get();'''
 
 -    Transaction trans = database.getTransaction();
 +    '''DBTransaction trans = transactionPool.beginWork();'''
 +    '''AccountDAO accountDAO = DAORegister.get().get(AccountDAO.class);'''
 
      try {
 -      trans.begin();
  
 -      if (database.hasPlayer(trans, username)) {
 +      if ('''accountDAO'''.hasPlayer(trans, username)) {
          return new AccountResult(Result.FAILED_PLAYER_EXISTS, username);
        }
  
 -      database.addPlayer(trans, username, Hash.hash(password), email);
 +      '''accountDAO'''.addPlayer(trans, username, Hash.hash(password), email);
  
 -      trans.commit();
 +      '''transactionPool.commit(trans);'''
  
        return new AccountResult(Result.OK_CREATED, username);
      } catch (SQLException e1) {
 
 -      try {
 -        trans.rollback();
 -      } catch (SQLException e2) {
 -        //logger.error("Rollback failed: ", e2);
 -        System.out.println("Rollback failed: " + e2);
 -      }
 +      '''transactionPool.rollback(trans);'''
 
        return new AccountResult(Result.FAILED_EXCEPTION, username);
      }
    }
 
 
    public CharacterResult createCharacter(String username, String character, RPObject tmpl) {
 
 -    IDatabase database = DatabaseFactory.getDatabase();
 +    '''TransactionPool transactionPool = TransactionPool.get();'''
 
 -    Transaction trans = database.getTransaction();
 +    '''DBTransaction trans = transactionPool.beginWork();'''
 +    CharacterDAO characterDAO = DAORegister.get().get(CharacterDAO.class);
 
      try {
 -      trans.begin();
  
 -      if (database.hasCharacter(trans, username, character)) {
 +      if ('''characterDAO'''.hasCharacter(trans, username, character)) {
          return new CharacterResult(Result.FAILED_PLAYER_EXISTS, character, tmpl);
        }
 
 @@ -196,18 +190,13 @@
 
 -      database.addCharacter(trans, username, character, object);
 +      '''characterDAO'''.addCharacter(trans, username, character, object);
 
 -      trans.commit();
 +      '''transactionPool.commit(trans);'''
 
        return new CharacterResult(Result.OK_CREATED, character, object);
      } catch (Exception e1) {
        //logger.warn("SQL exception while trying to create a new character: ", e1);
 
 -      try {
 -        trans.rollback();
 -      } catch (SQLException e2) {
 -        //logger.error("Rollback failed: ", e2);
 -        System.out.println("Rollback failed: " + e2);
 -      }
 +      '''transactionPool.rollback(trans);'''
 
        return new CharacterResult(Result.FAILED_EXCEPTION, character, tmpl);
      }
    }


[[Category:Marauroa]]