Package org.datanucleus.store.rdbms.query

Class ForwardQueryResult<E>

java.lang.Object

java.util.AbstractCollection<E>

java.util.AbstractList<E>

org.datanucleus.store.query.AbstractQueryResult<E>

org.datanucleus.store.rdbms.query.AbstractRDBMSQueryResult<E>

org.datanucleus.store.rdbms.query.ForwardQueryResult<E>

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.List<E>, org.datanucleus.store.query.QueryResult<E>

public final class ForwardQueryResult<E>
extends AbstractRDBMSQueryResult<E>
implements java.io.Serializable

Lazy collection results from a Query with the ResultSet in a forward direction. In general the actual result elements are only loaded when accessed with the exception of non-transactional or optimistic contexts that load the elements at initialisation.

If the query had a range defined and this was not handled in the datastore query then this QueryResult will skip the unrequired records and just return the range requested.

See Also:

Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	ForwardQueryResult.QueryResultIterator	An Iterator results of a pm.query.execute().iterator()

Field Summary

Fields

Modifier and Type	Field	Description
private java.util.Collection<java.lang.Object>	candidates	The candidate list restriction (optional).
protected boolean	moreResultSetRows	Whether there are still more rows to be processed in the ResultSet.
protected java.util.List<java.lang.Object>	resultIds
protected java.util.List<E>	resultObjs	The Result Objects.

Fields inherited from class org.datanucleus.store.rdbms.query.AbstractRDBMSQueryResult

applyRangeChecks, bulkLoadedMmds, bulkLoadedValueByMemberNumber, closeStatementWithResultSet, fp, rof, rs

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	Description
ForwardQueryResult(org.datanucleus.store.query.Query query, ResultObjectFactory<E> rof, java.sql.ResultSet rs, org.datanucleus.FetchPlan fp, java.util.Collection<java.lang.Object> candidates)	Constructor of the result from a Query.

Method Summary

Modifier and Type	Method	Description
private void	advanceToEndOfResultSet()	Internal method to advance to the end of the ResultSet, populating the resultObjs, and close the ResultSet when complete.
void	close()	Method to close the results, making the results unusable thereafter.
protected void	closeResults()	Internal method to close the ResultSet.
protected void	closingConnection()	Method called to inform the query result that the connection is being closed so perform any required operations now, or rest in peace.
boolean	contains(java.lang.Object o)	Method to check if the specified object is contained in this result.
boolean	containsAll(java.util.Collection c)	Method to check if all of the specified objects are contained here.
boolean	equals(java.lang.Object o)
E	get(int index)	Method to retrieve a particular element from the list.
protected int	getSizeUsingMethod()	Method to get the size using the "resultSizeMethod".
int	hashCode()
void	initialise()
boolean	isEmpty()	Accessor for whether there are any results.
java.util.Iterator<E>	iterator()	Accessor for an iterator for the results.
java.util.ListIterator<E>	listIterator()	Accessor for an iterator for the results.
protected E	nextResultSetElement()	Accessor for the next object from the ResultSet.
private void	processNumberOfResults(int number)	Method to advance through the results, processing the specified number of results.
java.lang.Object[]	toArray()	Method to return the results as an array.
<T> T[]	toArray(T[] a)	Method to return the results as an array.
protected java.lang.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.rdbms.query.AbstractRDBMSQueryResult

disconnect, registerMemberBulkResultSet, setCloseStatementWithResultSet

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

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

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

parallelStream, removeIf, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface java.util.List

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

Field Detail

moreResultSetRows

protected boolean moreResultSetRows

Whether there are still more rows to be processed in the ResultSet.

resultObjs

protected java.util.List<E> resultObjs

The Result Objects.

resultIds

protected java.util.List<java.lang.Object> resultIds

candidates

private java.util.Collection<java.lang.Object> candidates

The candidate list restriction (optional).

Constructor Detail

ForwardQueryResult

public ForwardQueryResult(org.datanucleus.store.query.Query query,
                          ResultObjectFactory<E> rof,
                          java.sql.ResultSet rs,
                          org.datanucleus.FetchPlan fp,
                          java.util.Collection<java.lang.Object> candidates)

Constructor of the result from a Query.

Parameters:

query - The Query

rof - The factory to retrieve results from

rs - The ResultSet from the Query Statement

fp - FetchPlan

candidates - Candidate elements

Method Detail

initialise

public void initialise()
                throws java.sql.SQLException

Specified by:

initialise in class AbstractRDBMSQueryResult<E>

Throws:

java.sql.SQLException

processNumberOfResults

private void processNumberOfResults(int number)

Method to advance through the results, processing the specified number of results.

Parameters:

number - Number of results (-1 means process all)

advanceToEndOfResultSet

private void advanceToEndOfResultSet()

Internal method to advance to the end of the ResultSet, populating the resultObjs, and close the ResultSet when complete.

nextResultSetElement

protected E nextResultSetElement()

Accessor for the next object from the ResultSet.

Returns:

The next element from the ResultSet.

closeResults

protected void closeResults()

Internal method to close the ResultSet.

Overrides:

closeResults in class AbstractRDBMSQueryResult<E>

close

public void close()

Method to close the results, making the results unusable thereafter.

Specified by:

close in interface org.datanucleus.store.query.QueryResult<E>

Overrides:

close in class AbstractRDBMSQueryResult<E>

closingConnection

protected void closingConnection()

Method called to inform the query result that the connection is being closed so perform any required operations now, or rest in peace.

Specified by:

closingConnection in class org.datanucleus.store.query.AbstractQueryResult<E>

iterator

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

Accessor for an iterator for the results.

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.List<E>

Specified by:

iterator in class org.datanucleus.store.query.AbstractQueryResult<E>

Returns:

The iterator

listIterator

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

Accessor for an iterator for the results.

Specified by:

listIterator in interface java.util.List<E>

Specified by:

listIterator in class org.datanucleus.store.query.AbstractQueryResult<E>

Returns:

The iterator

contains

public boolean contains(java.lang.Object o)

Method to check if the specified object is contained in this result.

Specified by:

contains in interface java.util.Collection<E>

Specified by:

contains in interface java.util.List<E>

Overrides:

contains in class org.datanucleus.store.query.AbstractQueryResult<E>

Parameters:

o - The object

Returns:

Whether it is contained here.

containsAll

public boolean containsAll(java.util.Collection c)

Method to check if all of the specified objects are contained here.

Specified by:

containsAll in interface java.util.Collection<E>

Specified by:

containsAll in interface java.util.List<E>

Overrides:

containsAll in class org.datanucleus.store.query.AbstractQueryResult<E>

Parameters:

c - The collection of objects

Returns:

Whether they are all contained here.

equals

public boolean equals(java.lang.Object o)

Specified by:

equals in interface java.util.Collection<E>

Specified by:

equals in interface java.util.List<E>

Overrides:

equals in class AbstractRDBMSQueryResult<E>

hashCode

public int hashCode()

Specified by:

hashCode in interface java.util.Collection<E>

Specified by:

hashCode in interface java.util.List<E>

Overrides:

hashCode in class AbstractRDBMSQueryResult<E>

get

public E get(int index)

Method to retrieve a particular element from the list.

Specified by:

get in interface java.util.List<E>

Specified by:

get in class org.datanucleus.store.query.AbstractQueryResult<E>

Parameters:

index - The index of the element

Returns:

The element at index

isEmpty

public boolean isEmpty()

Accessor for whether there are any results.

Specified by:

isEmpty in interface java.util.Collection<E>

Specified by:

isEmpty in interface java.util.List<E>

Overrides:

isEmpty in class org.datanucleus.store.query.AbstractQueryResult<E>

Returns:

true if these results are empty.

getSizeUsingMethod

protected int getSizeUsingMethod()

Method to get the size using the "resultSizeMethod". This implementation supports "LAST" method. Override this in subclasses to implement other methods.

Overrides:

getSizeUsingMethod in class org.datanucleus.store.query.AbstractQueryResult<E>

Returns:

The size

toArray

public java.lang.Object[] toArray()

Method to return the results as an array.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.List<E>

Overrides:

toArray in class org.datanucleus.store.query.AbstractQueryResult<E>

Returns:

The array.

toArray

public <T> T[] toArray(T[] a)

Method to return the results as an array.

Specified by:

toArray in interface java.util.Collection<E>

Specified by:

toArray in interface java.util.List<E>

Overrides:

toArray in class org.datanucleus.store.query.AbstractQueryResult<E>

Parameters:

a - The array to copy into.

Returns:

The array.

writeReplace

protected java.lang.Object writeReplace()
                                 throws java.io.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:

java.io.ObjectStreamException - Thrown if an error occurs