hirondelle.web4j.database
Class ForeignKeyException

Object
  Throwable
      Exception
          ServletException
              hirondelle.web4j.model.AppException
                  hirondelle.web4j.database.DAOException
                      hirondelle.web4j.database.ForeignKeyException

All Implemented Interfaces:

MessageList, Serializable

public final class ForeignKeyException
extends DAOException

Thrown when a violation of a foreign key constraint occurs in the datastore during an ADD, CHANGE, or DELETE operation.

This type of exception is singled out since it is so common. It allows Actions to catch this specific kind of exception.

For relational databases, this exception should be thrown for INSERT, UPDATE, or DELETE operation which may violate a foreign key constraint. Db, DbTx, and TxTemplate will throw a ForeignKeyException exception for SQLExceptions having an error code matching the ErrorCodeForForeignKey setting configured in web.xml. See web.xml for more information.

Typical Use Case

Here, an Action is calling a DAO method which may throw a ForeignKeyException:

private void deleteSomething throws DAOException {
  //this try..catch is needed only if the operation 
  //can have a foreign key problem
  try {
    dao.deleteSomething();
  }
  catch (ForeignKeyException ex){
    addError("Cannot delete. Referenced by some other item.");
  }
}

Here is the DAO operation which may have a foreign key constraint problem.

//It is highly recommended, but optional, to declare 
//ForeignKeyException in this method header, to bring 
//it to the attention of the caller
public deleteSomething() throws DAOException, ForeignKeyException {
  //...elided
}

See Also:

Serialized Form

Constructor Summary

ForeignKeyException(String aMessage, Throwable aRootCause)
Constructor.

Method Summary

Methods inherited from class hirondelle.web4j.model.AppException

add, add, add, getMessages, isEmpty, isNotEmpty, toString

Methods inherited from class ServletException

getRootCause

Methods inherited from class Throwable

fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

ForeignKeyException

public ForeignKeyException(String aMessage,
                           Throwable aRootCause)

Constructor.

Arguments are passed to DAOException.DAOException(String, Throwable).