//------------------------------------------------------
// Example of Dao, which is a generic DAO implementation
// based on JDO.
//------------------------------------------------------

// Persistence manager factory.
PersistenceManagerFactory factory = ...;

// Create a DAO with an entity class and the persistence manager factory.
Dao<Customer> dao = new Dao<Customer>(Customer.class, factory);

// Or using a static method.
Dao<Customer> dao = Dao.create(Customer.class, factory);

// Use the DAO.

// (1) Create an entity.
Customer customer = ...;
dao.put(customer);

// (2) Get an entity.
String customerId = ...;
Customer customer = dao.getById(customerId);

// (3) Delete an entity.
dao.delete(customer);

// (4) Delete an entity by ID.
dao.deleteById(customerId);

//------------------------------------------------------
// Example of TaskExecutor.
//------------------------------------------------------
// Persistence manager factory.
PersistenceManagerFactory factory = ...;

// Create a task executor.
TaskExecutor executor = new TaskExecutor(factory);

// Create a task.
Task task = new TaskAdapter() {
    @Override
    public void beforeTransactionBegin(PersistenceManager manager, Transaction tx) {
        tx.setOptimistic(false);
    }

    @Override
    public Object run(PersistenceManager manager) {
        ......
    }
};

// Execute the task.
executor.execute(task, true, 2);