com.j256.ormlite.dao

Class StreamableLazyForeignCollection<T,ID>

java.lang.Object

com.j256.ormlite.dao.BaseForeignCollection<T,ID>

com.j256.ormlite.dao.LazyForeignCollection<T,ID>

com.j256.ormlite.dao.StreamableLazyForeignCollection<T,ID>

All Implemented Interfaces:

CloseableIterable<T>, ForeignCollection<T>, Serializable, Iterable<T>, Collection<T>

public class StreamableLazyForeignCollection<T,ID>
extends LazyForeignCollection<T,ID>

Lazy foreign collection that provides better support for Streams if running with JDK8+. Fortuitously this can be compiled under JDK6 even with the unknown imports as long as the code doesn't use lambdas or any newer language features. This allows ORMLite to stay compatible with older class files but still provide better stream support for Java8+.

We are trying to fix the below code issue where Account.orders is a LazyForeignCollection.

 try (Stream stream = account.getOrders().stream();) {
        Order firstOrder = stream.findFirst().orElse(null);
 }
 

Without this class, the spliterator that is returned by spliterator() has the Spliterator.SIZED characteristic enabled which implies that the collection is in memory and it is cheap to estimate its size -- with a lazy collection, this can be very expensive and it causes the collection to be iterated across an additional time unnecessarily. Also, the Stream returned from the stream() method registers a BaseStream.onClose(Runnable) runnable to ensure that the iterator is properly closed once the BaseStream.close() method is called.

WARNING: because we are currently building with a JDK before 8, this class cannot be unit tested.

Author:

graywatson, zhemaituk

See Also:

Serialized Form

Field Summary

Fields inherited from class com.j256.ormlite.dao.BaseForeignCollection

dao

Constructor Summary

Constructors

Constructor and Description
StreamableLazyForeignCollection(Dao<T,ID> dao, Object parent, Object parentId, FieldType foreignFieldType, String orderColumn, boolean orderAscending)

Method Summary

Modifier and Type	Method and Description
CloseableSpliterator<T>	spliterator()
java.util.stream.Stream<T>	stream()

Methods inherited from class com.j256.ormlite.dao.LazyForeignCollection

closeableIterator, closeableIterator, closeLastIterator, contains, containsAll, equals, getWrappedIterable, getWrappedIterable, hashCode, isEager, isEmpty, iterator, iterator, iteratorThrow, iteratorThrow, refreshAll, refreshCollection, remove, removeAll, size, toArray, toArray, toList, updateAll

Methods inherited from class com.j256.ormlite.dao.BaseForeignCollection

add, addAll, clear, getDao, getPreparedQuery, refresh, retainAll, update

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

parallelStream, removeIf

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

StreamableLazyForeignCollection

public StreamableLazyForeignCollection(Dao<T,ID> dao,
                                       Object parent,
                                       Object parentId,
                                       FieldType foreignFieldType,
                                       String orderColumn,
                                       boolean orderAscending)

Method Detail

spliterator

public CloseableSpliterator<T> spliterator()

stream

public java.util.stream.Stream<T> stream()