com.atlassian.jira.ofbiz

Class PagedDatabaseIterable<E,K>

java.lang.Object

com.atlassian.jira.ofbiz.PagedDatabaseIterable<E,K>

All Implemented Interfaces:

EnclosedIterable<E>, Sized

public abstract class PagedDatabaseIterable<E,K>
extends Object
implements EnclosedIterable<E>

A abstract implementation of EnclosedIterable that takes a list of ids and then pages them by opening an OfBizListIterator for each page.

This implementation supports preserving the order of the elements in the returned list but will load all the elements into memory in order to do so.

This implementation uses the DatabaseIterator but implements paging and sorting on top of it.

Since:

v3.13

Nested Class Summary

Nested classes/interfaces inherited from interface com.atlassian.jira.util.collect.EnclosedIterable

EnclosedIterable.Functions, EnclosedIterable.ListResolver<T>

Constructor Summary

Constructors

Constructor and Description
PagedDatabaseIterable(List<K> ids) Use where the order of the result is not important.
PagedDatabaseIterable(List<K> ids, Resolver<E,K> keyResolver) Use where the order of the result is important.
PagedDatabaseIterable(List<K> ids, Resolver<E,K> keyResolver, int pageSize) Use where the order of the result is important.

Method Summary

Modifier and Type	Method and Description
protected abstract OfBizListIterator	createListIterator(List<K> ids) Create a new iterator from the subset of ids.
void	foreach(Consumer<E> consumer) Apply the sink to all elements in the Collection.
protected abstract Resolver<org.ofbiz.core.entity.GenericValue,E>	getResolver() Used to turn generic values into Domain objects
boolean	isEmpty()
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

PagedDatabaseIterable

public PagedDatabaseIterable(List<K> ids)

Use where the order of the result is not important.

Parameters:

ids - a List must not be null

PagedDatabaseIterable

public PagedDatabaseIterable(List<K> ids,
                             Resolver<E,K> keyResolver)

Use where the order of the result is important.

Parameters:

ids - a List must not be null

keyResolver - to get a domain object's key (ie. the element in the ids list). Null if sort order is unimportant

PagedDatabaseIterable

public PagedDatabaseIterable(List<K> ids,
                             Resolver<E,K> keyResolver,
                             int pageSize)

Use where the order of the result is important.

Parameters:

ids - a List must not be null

keyResolver - to get a domain object's key (ie. the element in the ids list). Null if sort order is unimportant

pageSize - the size of the pages to use

Method Detail

foreach

public final void foreach(Consumer<E> consumer)

Description copied from interface: EnclosedIterable

Apply the sink to all elements in the Collection.

Specified by:

foreach in interface EnclosedIterable<E>

createListIterator

protected abstract OfBizListIterator createListIterator(List<K> ids)

Create a new iterator from the subset of ids.

Parameters:

ids - list of ids

Returns:

an instance of OfBizListIterator

getResolver

protected abstract Resolver<org.ofbiz.core.entity.GenericValue,E> getResolver()

Used to turn generic values into Domain objects

Returns:

a resolver

size

public final int size()

Specified by:

size in interface EnclosedIterable<E>

Specified by:

size in interface Sized

Returns:

the likely size of the objects passed into the sink in EnclosedIterable.foreach(Consumer). Be careful depending on this size being exact, as in many cases its best efforts value or may be unstable due to concurrent changes.

isEmpty

public boolean isEmpty()

Specified by:

isEmpty in interface EnclosedIterable<E>

Specified by:

isEmpty in interface Sized

Returns:

true if the there is no data behind it.