org.minimalj.repository.list

Class RelationList<PARENT,ELEMENT>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<ELEMENT>

org.minimalj.repository.list.RelationList<PARENT,ELEMENT>

Type Parameters:

PARENT - Class of the parent entity

ELEMENT - Class of the element entity

All Implemented Interfaces:

Serializable, Iterable<ELEMENT>, Collection<ELEMENT>, List<ELEMENT>

public class RelationList<PARENT,ELEMENT>
extends AbstractList<ELEMENT>
implements Serializable

The class RelationList is used as a specialized list used if a (main) entity has a one-to-many relation to element entities (that have an id of their own).

RelationLists load their content lazy. At the beginning only the size is calculated. But the element entities are not loaded when the main entity is loaded. When a get method is called on the list the requested element is loaded through the backend. If you want avoid too many server roundtrips and you know that a lot of elements will be requested you should use the subList method. The subList method of a RelationList will return a unmodifiable List with all elements of the selected range preloaded.

Normally the use of this class should be completely transparent. But you have to know the additional meaning of the subList method.

As soon as this List should be changed it is loaded completely. This could be improved but at the moment it is the easiest way to make sure that the changes as saved when the main entity is saved.

See Also:

Serialized Form

Field Summary

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor and Description
RelationList(Repository repository, Class<ELEMENT> elementClass, PARENT parent, String crossName)

Method Summary

Modifier and Type	Method and Description
void	add(int index, ELEMENT element)
ELEMENT	get(int index)
boolean	isLoaded()
ELEMENT	remove(int index)
ELEMENT	set(int index, ELEMENT element)
int	size()
List<ELEMENT>	subList(int fromIndex, int toIndex)

Methods inherited from class java.util.AbstractList

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

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

RelationList

public RelationList(Repository repository,
                    Class<ELEMENT> elementClass,
                    PARENT parent,
                    String crossName)

Method Detail

isLoaded

public boolean isLoaded()

get

public ELEMENT get(int index)

Specified by:

get in interface List<ELEMENT>

Specified by:

get in class AbstractList<ELEMENT>

subList

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

Specified by:

subList in interface List<ELEMENT>

Overrides:

subList in class AbstractList<ELEMENT>

size

public int size()

Specified by:

size in interface Collection<ELEMENT>

Specified by:

size in interface List<ELEMENT>

Specified by:

size in class AbstractCollection<ELEMENT>

set

public ELEMENT set(int index,
                   ELEMENT element)

Specified by:

set in interface List<ELEMENT>

Overrides:

set in class AbstractList<ELEMENT>

add

public void add(int index,
                ELEMENT element)

Specified by:

add in interface List<ELEMENT>

Overrides:

add in class AbstractList<ELEMENT>

remove

public ELEMENT remove(int index)

Specified by:

remove in interface List<ELEMENT>

Overrides:

remove in class AbstractList<ELEMENT>