org.datanucleus.store.mongodb.query

Class LazyLoadQueryResult

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

org.datanucleus.store.query.AbstractQueryResult

org.datanucleus.store.mongodb.query.LazyLoadQueryResult

All Implemented Interfaces:

Serializable, Iterable, Collection, List, org.datanucleus.store.query.QueryResult

public class LazyLoadQueryResult
extends org.datanucleus.store.query.AbstractQueryResult

QueryResult for MongoDB queries that tries to lazy load results from the provided DBCursor(s) so to avoid problems with memory.

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected List<org.datanucleus.store.mongodb.query.LazyLoadQueryResult.CandidateClassResult>	candidateResults Candidate results for this query that have not been (completely) processed yet.
protected Iterator<com.mongodb.DBObject>	currentCursorIterator Iterator for the DBCursor that is being processed (if any).
protected org.datanucleus.ExecutionContext	ec
protected Map<Integer,Object>	itemsByIndex Map of object, keyed by the index (0, 1, etc).

Fields inherited from class org.datanucleus.store.query.AbstractQueryResult

api, closed, connectionListeners, loadResultsAtCommit, query, resultSizeMethod, size

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

Constructors

Constructor and Description
LazyLoadQueryResult(org.datanucleus.store.query.Query q)

Method Summary

Modifier and Type	Method and Description
void	addCandidateResult(org.datanucleus.metadata.AbstractClassMetaData cmd, com.mongodb.DBCursor cursor, int[] fpMembers)
void	close()
protected void	closeResults()
protected void	closingConnection()
boolean	contains(Object o)
boolean	containsAll(Collection c)
boolean	equals(Object o)
Object	get(int index)
protected Object	getNextObject() Method to extract the next object from the candidateResults (if there is one).
boolean	getOrderProcessed()
boolean	getRangeProcessed()
protected int	getSizeUsingMethod()
int	hashCode()
Iterator	iterator()
ListIterator	listIterator()
void	setOrderProcessed(boolean processed) Allow the creator to signify that the query order was processed when generating this QueryResult
void	setRangeProcessed(boolean processed) Allow the creator to signify that the query range was processed when generating this QueryResult
protected Object	writeReplace() Handle serialisation by returning a java.util.ArrayList of all of the results for this query after disconnecting the query which has the consequence of enforcing the load of all objects.

Methods inherited from class org.datanucleus.store.query.AbstractQueryResult

add, add, addAll, addConnectionListener, assertIsOpen, clear, disconnect, indexOf, isEmpty, isOpen, lastIndexOf, remove, set, size, subList, toArray, toArray

Methods inherited from class java.util.AbstractList

listIterator, removeRange

Methods inherited from class java.util.AbstractCollection

addAll, remove, removeAll, retainAll, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

addAll, parallelStream, remove, removeAll, removeIf, retainAll, spliterator, stream

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.List

addAll, remove, removeAll, replaceAll, retainAll, sort, spliterator

Field Detail

ec

protected org.datanucleus.ExecutionContext ec

candidateResults

protected List<org.datanucleus.store.mongodb.query.LazyLoadQueryResult.CandidateClassResult> candidateResults

Candidate results for this query that have not been (completely) processed yet.

currentCursorIterator

protected Iterator<com.mongodb.DBObject> currentCursorIterator

Iterator for the DBCursor that is being processed (if any).

itemsByIndex

protected Map<Integer,Object> itemsByIndex

Map of object, keyed by the index (0, 1, etc).

Constructor Detail

LazyLoadQueryResult

public LazyLoadQueryResult(org.datanucleus.store.query.Query q)

Method Detail

addCandidateResult

public void addCandidateResult(org.datanucleus.metadata.AbstractClassMetaData cmd,
                               com.mongodb.DBCursor cursor,
                               int[] fpMembers)

setRangeProcessed

public void setRangeProcessed(boolean processed)

Allow the creator to signify that the query range was processed when generating this QueryResult

Parameters:

processed - Whether the range was processed when the query was executed

getRangeProcessed

public boolean getRangeProcessed()

setOrderProcessed

public void setOrderProcessed(boolean processed)

Allow the creator to signify that the query order was processed when generating this QueryResult

Parameters:

processed - Whether the order was processed when the query was executed

getOrderProcessed

public boolean getOrderProcessed()

closingConnection

protected void closingConnection()

Specified by:

closingConnection in class org.datanucleus.store.query.AbstractQueryResult

close

public void close()

Specified by:

close in interface org.datanucleus.store.query.QueryResult

Overrides:

close in class org.datanucleus.store.query.AbstractQueryResult

closeResults

protected void closeResults()

Specified by:

closeResults in class org.datanucleus.store.query.AbstractQueryResult

getSizeUsingMethod

protected int getSizeUsingMethod()

Overrides:

getSizeUsingMethod in class org.datanucleus.store.query.AbstractQueryResult

get

public Object get(int index)

Specified by:

get in interface List

Specified by:

get in class org.datanucleus.store.query.AbstractQueryResult

getNextObject

protected Object getNextObject()

Method to extract the next object from the candidateResults (if there is one). If a result is present, this puts it into "itemsByIndex". Returns null if no more results.

Returns:

The next result (or null if no more).

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection

Specified by:

contains in interface List

Overrides:

contains in class org.datanucleus.store.query.AbstractQueryResult

containsAll

public boolean containsAll(Collection c)

Specified by:

containsAll in interface Collection

Specified by:

containsAll in interface List

Overrides:

containsAll in class org.datanucleus.store.query.AbstractQueryResult

iterator

public Iterator iterator()

Specified by:

iterator in interface Iterable

Specified by:

iterator in interface Collection

Specified by:

iterator in interface List

Specified by:

iterator in class org.datanucleus.store.query.AbstractQueryResult

listIterator

public ListIterator listIterator()

Specified by:

listIterator in interface List

Specified by:

listIterator in class org.datanucleus.store.query.AbstractQueryResult

equals

public boolean equals(Object o)

Specified by:

equals in interface Collection

Specified by:

equals in interface List

Specified by:

equals in class org.datanucleus.store.query.AbstractQueryResult

hashCode

public int hashCode()

Specified by:

hashCode in interface Collection

Specified by:

hashCode in interface List

Overrides:

hashCode in class org.datanucleus.store.query.AbstractQueryResult

writeReplace

protected Object writeReplace()
                       throws ObjectStreamException

Handle serialisation by returning a java.util.ArrayList of all of the results for this query after disconnecting the query which has the consequence of enforcing the load of all objects.

Returns:

The object to serialise

Throws:

ObjectStreamException - Throw if there is a problem in disconnect