Package io.ebean

Interface QueryIterator<T>

  • Type Parameters:
    T - the type of entity bean in the iteration
    All Superinterfaces:
    AutoCloseable, Closeable, Iterator<T>
    public interface QueryIterator<T>
extends Iterator<T>, Closeable
    Used to provide iteration over query results.

    This can be used when you want to process a very large number of results and means that you don't have to hold all the results in memory at once (unlike findList(), findSet() etc where all the beans are held in the List or Set etc).

    Note that findIterate (and findEach and findEachWhile) uses a "per graph" persistence context scope and adjusts jdbc fetch buffer size for large queries. As such it is better to use findList for small queries.

    Remember that with QueryIterator you must call close() when you have finished iterating the results. Use "try with resources" or ensure it is closed in a finally block.

    Try finally style

    

  Query<Customer> query = database.find(Customer.class)
     .where().gt("id", 0)
     .order("id")
     .setMaxRows(2);

  QueryIterator<Customer> it = query.findIterate();
  try {
    while (it.hasNext()) {
      Customer customer = it.next();
      // do something with customer ...
    }
  } finally {
    // close the underlying resources
    it.close();
  }

    Try with resources style

    

  // try with resources
  try (QueryIterator<Customer> it = query.findIterate()) {
    while (it.hasNext()) {
      Customer customer = it.next();
      // do something with customer ...
    }
  }