Module io.ebean.api

Package io.ebean

Interface QueryIterator<T>

Type Parameters:

T - the type of entity bean in the iteration

All Superinterfaces:

AutoCloseable, Iterator<T>

public interface QueryIterator<T>
extends Iterator<T>, AutoCloseable

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 ...
    }
  }

 

Method Summary

Modifier and Type	Method	Description
void	close()	Close the underlying resources held by this iterator.
boolean	hasNext()	Returns true if the iteration has more elements.
T	next()	Returns the next element in the iteration.

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Method Details

hasNext

boolean hasNext()

Returns true if the iteration has more elements.

Specified by:

hasNext in interface Iterator<T>

next

T next()

Returns the next element in the iteration.

Specified by:

next in interface Iterator<T>

close

void close()

Close the underlying resources held by this iterator.

Specified by:

close in interface AutoCloseable