info.aduna.collections.iterators
Class DelayedIterator<E>

java.lang.Object
  info.aduna.iteration.CloseableIterationBase<E,X>
      info.aduna.iteration.DelayedIteration<E,RuntimeException>
          info.aduna.collections.iterators.DelayedIterator<E>

All Implemented Interfaces:

CloseableIterator<E>, CloseableIteration<E,RuntimeException>, Iteration<E,RuntimeException>, Closeable, Iterator<E>

public abstract class DelayedIterator<E>
extends DelayedIteration<E,RuntimeException>
implements CloseableIterator<E>

An iterator that delays the creation of the underlying iterator until it is being accessed. This is mainly useful for situations where iterator creation adds considerable overhead but where the iterator may not actually be used, or where a created iterator consumes scarce resources like JDBC-connections or memory. Subclasses must implement the createIterator method, which is called once when the iterator is first needed.

Field Summary

Fields inherited from class info.aduna.iteration.CloseableIterationBase

logger

Constructor Summary

DelayedIterator()

Method Summary

protected Iteration<? extends E,RuntimeException>	createIteration() Creates the iteration that should be iterated over.
protected abstract Iterator<? extends E>	createIterator() Creates the iterator that should be iterated over.

Methods inherited from class info.aduna.iteration.DelayedIteration

handleClose, hasNext, next, remove

Methods inherited from class info.aduna.iteration.CloseableIterationBase

close, isClosed

Methods inherited from class java.lang.Object

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

Methods inherited from interface info.aduna.collections.iterators.CloseableIterator

close

Methods inherited from interface java.util.Iterator

hasNext, next, remove

Constructor Detail

DelayedIterator

public DelayedIterator()

Method Detail

createIteration

protected final Iteration<? extends E,RuntimeException> createIteration()
                                                                 throws RuntimeException

Description copied from class: DelayedIteration

Creates the iteration that should be iterated over. This method is called only once, when the iteration is first needed.

Specified by:

createIteration in class DelayedIteration<E,RuntimeException>

Throws:

RuntimeException

createIterator

protected abstract Iterator<? extends E> createIterator()

Creates the iterator that should be iterated over. This method is called only once, when the iterator is first needed.