io.realm

Class RealmResults<E extends RealmObject>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

io.realm.RealmResults<E>

Type Parameters:

E - The class of objects in this list

All Implemented Interfaces:

java.lang.Iterable<E>, java.util.Collection<E>, java.util.List<E>

public class RealmResults<E extends RealmObject>
extends java.util.AbstractList<E>

This class holds all the matches of a RealmQuery for a given Realm. The objects are not copied from the Realm to the RealmResults list, but are just referenced from the RealmResult instead. This saves memory and increases speed.

RealmResults are live views, which means that if it is on an Looper thread, it will automatically update its query results after a transaction has been committed. If on a non-looper thread, Realm.refresh() must be called to update the results.

Updates to RealmObjects from a RealmResults list must be done from within a transaction and the modified objects are persisted to the Realm file during the commit of the transaction.

A RealmResults object cannot be passed between different threads.

Notice that a RealmResults is never null not even in the case where it contains no objects. You should always use the size() method to check if a RealmResults is empty or not.

See Also:

RealmQuery.findAll(), Realm.allObjects(Class), Realm.beginTransaction()

Field Summary

Fields

Modifier and Type	Field and Description
static boolean	SORT_ORDER_ASCENDING
static boolean	SORT_ORDER_DESCENDING

Method Summary

Methods

Modifier and Type	Method and Description
boolean	add(E element) Deprecated.
void	add(int index, E element) Deprecated.
double	average(java.lang.String fieldName) Returns the average of a given field.
void	clear() Removes all objects from the list.
E	first() Get the first object from the list.
E	get(int location) Returns the element at the specified location in this list.
int	indexOf(java.lang.Object o) This method is not supported.
java.util.Iterator<E>	iterator() Returns an iterator for the results of a query.
E	last() Get the last object from the list.
java.util.ListIterator<E>	listIterator() Returns a list iterator for the results of a query.
java.util.ListIterator<E>	listIterator(int location) Returns a list iterator on the results of a query.
java.lang.Number	max(java.lang.String fieldName) Find the maximum value of a field.
java.util.Date	maxDate(java.lang.String fieldName) Find the maximum date.
java.lang.Number	min(java.lang.String fieldName) Find the minimum value of a field.
java.util.Date	minDate(java.lang.String fieldName) Find the minimum date.
E	remove(int index) Removes an object at a given index.
void	removeLast() Removes and returns the last object in the list.
int	size() Returns the number of elements in this query result.
void	sort(java.lang.String fieldName) Sort (ascending) an existing RealmResults.
void	sort(java.lang.String[] fieldNames, boolean[] sortAscending) Sort existing RealmResults.
void	sort(java.lang.String fieldName, boolean sortAscending) Sort existing RealmResults.
void	sort(java.lang.String fieldName1, boolean sortAscending1, java.lang.String fieldName2, boolean sortAscending2) Sort existing RealmResults using two fields.
void	sort(java.lang.String fieldName1, boolean sortAscending1, java.lang.String fieldName2, boolean sortAscending2, java.lang.String fieldName3, boolean sortAscending3) Sort existing RealmResults using three fields.
java.lang.Number	sum(java.lang.String fieldName) Calculate the sum of a given field.
RealmQuery<E>	where() Returns a typed RealmQuery, which can be used to query for specific objects of this type.

Methods inherited from class java.util.AbstractList

addAll, equals, hashCode, lastIndexOf, set, subList

Methods inherited from class java.util.AbstractCollection

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

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface java.util.List

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

Field Detail

SORT_ORDER_ASCENDING

public static final boolean SORT_ORDER_ASCENDING

See Also:

Constant Field Values

SORT_ORDER_DESCENDING

public static final boolean SORT_ORDER_DESCENDING

See Also:

Constant Field Values

Method Detail

where

public RealmQuery<E> where()

Returns a typed RealmQuery, which can be used to query for specific objects of this type.

Returns:

A typed RealmQuery

See Also:

RealmQuery

get

public E get(int location)

Returns the element at the specified location in this list.

Specified by:

get in interface java.util.List<E extends RealmObject>

Specified by:

get in class java.util.AbstractList<E extends RealmObject>

Parameters:

location - the index of the element to return.

Returns:

the element at the specified index.

Throws:

java.lang.IndexOutOfBoundsException - if location < 0 || location >= size()

indexOf

public int indexOf(java.lang.Object o)

This method is not supported.

Specified by:

indexOf in interface java.util.List<E extends RealmObject>

Overrides:

indexOf in class java.util.AbstractList<E extends RealmObject>

Throws:

java.lang.NoSuchMethodError - always.

first

public E first()

Get the first object from the list.

Returns:

The first object.

Throws:

java.lang.ArrayIndexOutOfBoundsException - if RealmResults is empty.

last

public E last()

Get the last object from the list.

Returns:

The last object.

Throws:

java.lang.ArrayIndexOutOfBoundsException - if RealmResults is empty.

iterator

public java.util.Iterator<E> iterator()

Returns an iterator for the results of a query. Any change to Realm while iterating will cause this iterator to throw a ConcurrentModificationException if accessed.

Specified by:

iterator in interface java.lang.Iterable<E extends RealmObject>

Specified by:

iterator in interface java.util.Collection<E extends RealmObject>

Specified by:

iterator in interface java.util.List<E extends RealmObject>

Overrides:

iterator in class java.util.AbstractList<E extends RealmObject>

Returns:

an iterator on the elements of this list.

See Also:

Iterator

listIterator

public java.util.ListIterator<E> listIterator()

Returns a list iterator for the results of a query. Any change to Realm while iterating will cause the iterator to throw a ConcurrentModificationException if accessed.

Specified by:

listIterator in interface java.util.List<E extends RealmObject>

Overrides:

listIterator in class java.util.AbstractList<E extends RealmObject>

Returns:

a ListIterator on the elements of this list.

See Also:

ListIterator

listIterator

public java.util.ListIterator<E> listIterator(int location)

Returns a list iterator on the results of a query. Any change to Realm while iterating will cause the iterator to throw a ConcurrentModificationException if accessed.

Specified by:

listIterator in interface java.util.List<E extends RealmObject>

Overrides:

listIterator in class java.util.AbstractList<E extends RealmObject>

Parameters:

location - the index at which to start the iteration.

Returns:

a ListIterator on the elements of this list.

Throws:

java.lang.IndexOutOfBoundsException - if location < 0 || location > size()

See Also:

ListIterator

sort

public void sort(java.lang.String fieldName)

Sort (ascending) an existing RealmResults.

Parameters:

fieldName - The field name to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

Throws:

java.lang.IllegalArgumentException - if field name does not exist.

sort

public void sort(java.lang.String fieldName,
        boolean sortAscending)

Sort existing RealmResults.

Parameters:

fieldName - The field name to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortAscending - The direction to sort by; if true ascending, otherwise descending You can use the constants SORT_ORDER_ASCENDING and SORT_ORDER_DESCENDING for readability.

Throws:

java.lang.IllegalArgumentException - if field name does not exist.

sort

public void sort(java.lang.String[] fieldNames,
        boolean[] sortAscending)

Sort existing RealmResults.

Parameters:

fieldNames - an array of field names to sort by. Only fields of type boolean, short, int, long, float, double, Date, and String are supported.

sortAscending - The directions to sort by; if true ascending, otherwise descending You can use the constants SORT_ORDER_ASCENDING and SORT_ORDER_DESCENDING for readability.

Throws:

java.lang.IllegalArgumentException - if a field name does not exist.

sort

public void sort(java.lang.String fieldName1,
        boolean sortAscending1,
        java.lang.String fieldName2,
        boolean sortAscending2)

Sort existing RealmResults using two fields.

Parameters:

fieldName1 - first field name.

sortAscending1 - sort order for first field.

fieldName2 - second field name.

sortAscending2 - sort order for second field.

Throws:

java.lang.IllegalArgumentException - if a field name does not exist.

sort

public void sort(java.lang.String fieldName1,
        boolean sortAscending1,
        java.lang.String fieldName2,
        boolean sortAscending2,
        java.lang.String fieldName3,
        boolean sortAscending3)

Sort existing RealmResults using three fields.

Parameters:

fieldName1 - first field name.

sortAscending1 - sort order for first field.

fieldName2 - second field name.

sortAscending2 - sort order for second field.

fieldName3 - third field name.

sortAscending3 - sort order for third field.

Throws:

java.lang.IllegalArgumentException - if a field name does not exist.

size

public int size()

Returns the number of elements in this query result.

Specified by:

size in interface java.util.Collection<E extends RealmObject>

Specified by:

size in interface java.util.List<E extends RealmObject>

Specified by:

size in class java.util.AbstractCollection<E extends RealmObject>

Returns:

the number of elements in this query result.

min

public java.lang.Number min(java.lang.String fieldName)

Find the minimum value of a field.

Parameters:

fieldName - The field to look for a minimum on. Only int, float, and double are supported.

Returns:

The minimum value.

Throws:

java.lang.IllegalArgumentException - if field is not int, float or double.

minDate

public java.util.Date minDate(java.lang.String fieldName)

Find the minimum date.

Parameters:

fieldName - The field to look for the minimum date. If fieldName is not of Date type, an exception is thrown.

Returns:

The minimum date.

Throws:

java.lang.IllegalArgumentException - if fieldName is not a Date field.

max

public java.lang.Number max(java.lang.String fieldName)

Find the maximum value of a field.

Parameters:

fieldName - The field to look for a maximum on. Only int, float, and double are supported.

Returns:

The maximum value.

Throws:

java.lang.IllegalArgumentException - if field is not int, float or double.

maxDate

public java.util.Date maxDate(java.lang.String fieldName)

Find the maximum date.

Parameters:

fieldName - The field to look for the maximum date. If fieldName is not of Date type, an exception is thrown.

Returns:

The maximum date.

Throws:

java.lang.IllegalArgumentException - if fieldName is not a Date field.

sum

public java.lang.Number sum(java.lang.String fieldName)

Calculate the sum of a given field.

Parameters:

fieldName - The field to sum. Only int, float, and double are supported.

Returns:

The sum.

Throws:

java.lang.IllegalArgumentException - if field is not int, float or double.

average

public double average(java.lang.String fieldName)

Returns the average of a given field.

Parameters:

fieldName - The field to calculate average on. Only properties of type int, float and double are supported.

Returns:

The average for the given field amongst objects in an RealmList. This will be of type double for both float and double field.

Throws:

java.lang.IllegalArgumentException - if field is not int, float or double.

remove

public E remove(int index)

Removes an object at a given index. This also deletes the object from the underlying Realm. Using this method while iterating the list can result in a undefined behavior. Use RealmResults.RealmResultsIterator.remove() instead.

Specified by:

remove in interface java.util.List<E extends RealmObject>

Overrides:

remove in class java.util.AbstractList<E extends RealmObject>

Parameters:

index - The array index identifying the object to be removed.

Returns:

Always return null.

removeLast

public void removeLast()

Removes and returns the last object in the list. This also deletes the object from the underlying Realm. Using this method while iterating the list can result in a undefined behavior. Use removeLast() instead.

clear

public void clear()

Removes all objects from the list. This also deletes the objects from the underlying Realm.

Specified by:

clear in interface java.util.Collection<E extends RealmObject>

Specified by:

clear in interface java.util.List<E extends RealmObject>

Overrides:

clear in class java.util.AbstractList<E extends RealmObject>

add

@Deprecated
public boolean add(E element)

Deprecated.

Specified by:

add in interface java.util.Collection<E extends RealmObject>

Specified by:

add in interface java.util.List<E extends RealmObject>

Overrides:

add in class java.util.AbstractList<E extends RealmObject>

add

@Deprecated
public void add(int index,
                  E element)

Deprecated.

Specified by:

add in interface java.util.List<E extends RealmObject>

Overrides:

add in class java.util.AbstractList<E extends RealmObject>