org.minimalj.repository.list

Class QueryResultList<T>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<T>

org.minimalj.repository.list.QueryResultList<T>

Type Parameters:

T - Class of the Elements

All Implemented Interfaces:

Serializable, Iterable<T>, Collection<T>, List<T>, Sortable

public class QueryResultList<T>
extends AbstractList<T>
implements Sortable, Serializable

A repository may (but is not required to) return a QueryResultList when the find method is called. Only the size of the list is calculated when a QueryResultList is calculated. Every element read with a get(index) is loaded from the backend.

If you know you will use many elements of the List use the subList method to load a complete range of elements in a unmodifiable List. This is how such lists are used by the Frontend

A QueryResultList is unmodifiable. Every call of a add or remove method will result in a UnsupportedOperationException.

If the database has changed before you call a get or subList method you may get null as element or a unexpected reduced sub list. You don't get an exception in that cases.

QueryResultList is Sortable. The order of the elements can be changed at any time. The size of the List is not recalculated and the sub List created before a sort are not updated. Of course this is mainly used by a Frontend. Business methods should execute a new find on the Repository / Backend.

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor and Description
QueryResultList(Repository repository, Class<T> clazz, Query query)

Method Summary

Modifier and Type	Method and Description
boolean	canSortBy(Object sortKey)
T	get(int index)
int	size()
void	sort(Object[] sortKeys, boolean[] sortDirections)
List<T>	subList(int fromIndex, int toIndex)

Methods inherited from class java.util.AbstractList

add, add, addAll, clear, equals, hashCode, indexOf, iterator, lastIndexOf, listIterator, listIterator, remove, removeRange, set

Methods inherited from class java.util.AbstractCollection

addAll, contains, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.List

addAll, contains, containsAll, isEmpty, remove, removeAll, replaceAll, retainAll, sort, spliterator, toArray, toArray

Methods inherited from interface java.util.Collection

parallelStream, removeIf, stream

Methods inherited from interface java.lang.Iterable

forEach

Constructor Detail

QueryResultList

public QueryResultList(Repository repository,
                       Class<T> clazz,
                       Query query)

Method Detail

get

public T get(int index)

Specified by:

get in interface List<T>

Specified by:

get in class AbstractList<T>

subList

public List<T> subList(int fromIndex,
                       int toIndex)

Specified by:

subList in interface List<T>

Overrides:

subList in class AbstractList<T>

size

public int size()

Specified by:

size in interface Collection<T>

Specified by:

size in interface List<T>

Specified by:

size in class AbstractCollection<T>

sort

public void sort(Object[] sortKeys,
                 boolean[] sortDirections)

Specified by:

sort in interface Sortable

canSortBy

public boolean canSortBy(Object sortKey)

Specified by:

canSortBy in interface Sortable