org.datanucleus.store.query
Class AbstractQueryResult

java.lang.Object
  java.util.AbstractCollection<E>
      java.util.AbstractList
          org.datanucleus.store.query.AbstractQueryResult

All Implemented Interfaces:

java.io.Serializable, java.lang.Iterable, java.util.Collection, java.util.List, QueryResult

public abstract class AbstractQueryResult
extends java.util.AbstractList
implements QueryResult, java.io.Serializable

Abstract representation of a QueryResult. Provides default implementations of the majority of list methods that we aren't likely to be providing in a concrete query result. This class is used where your query implementation needs to return a wrapper to a List so that you can intercept calls and convert a row of the results into object(s), to avoid full instantiation at creation.

See Also:

Serialized Form

Field Summary

protected boolean	closed Whether the results are close.
protected java.util.List	connectionListeners List of listeners to notify when the query results are closed.
protected static Localiser	LOCALISER Localiser for messages.
protected Query	query The Query object.

Fields inherited from class java.util.AbstractList

modCount

Constructor Summary

AbstractQueryResult(Query query)
Constructor of the result from a Query.

Method Summary

void	add(int index, java.lang.Object element) Method to add a result.
boolean	add(java.lang.Object o) Method to add results.
boolean	addAll(int index, java.util.Collection c) Method to add results.
void	addConnectionListener(ManagedConnectionResourceListener listener) Method to register a listener to be notified when the query result is closing.
protected void	assertIsOpen() Internal method to throw an Exception if the ResultSet is open.
void	clear() Method to clear the results.
void	close() Method to close the results, meaning that they are inaccessible after this point.
protected abstract void	closeResults() Inform the query result that we are closing the results now.
protected abstract void	closingConnection() Inform the query result that the connection is being closed so perform any 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.
void	disconnect() Method to disconnect the results from the ObjectManager, meaning that thereafter it just behaves like a List.
abstract boolean	equals(java.lang.Object o) Equality operator for QueryResults.
abstract java.lang.Object	get(int index) Method to retrieve a particular element from the list.
int	hashCode() Accessor for the hashcode of this object
int	indexOf(java.lang.Object o) Method to check the index of a result.
boolean	isEmpty() Returns true if this collection contains no elements.
protected boolean	isOpen() Accessor whether the results are open.
abstract java.util.Iterator	iterator() Accessor for an iterator for the results.
int	lastIndexOf(java.lang.Object o) Method to check the last index of a result.
abstract java.util.ListIterator	listIterator() Accessor for a list iterator for the results.
java.lang.Object	remove(int index) Method to remove a result.
java.lang.Object	set(int index, java.lang.Object element) Method to set the position of a result.
abstract int	size() Method to return the size of the result.
java.util.List	subList(int fromIndex, int toIndex) Method return a sub list of results.
java.lang.Object[]	toArray() Method to return the results as an array.
java.lang.Object[]	toArray(java.lang.Object[] a) Method to return the results as an array.

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, remove, removeAll, retainAll

Methods inherited from interface java.util.List

addAll, remove, removeAll, retainAll

Field Detail

LOCALISER

protected static final Localiser LOCALISER

Localiser for messages.

query

protected Query query

The Query object.

closed

protected boolean closed

Whether the results are close.

connectionListeners

protected java.util.List connectionListeners

List of listeners to notify when the query results are closed.

Constructor Detail

AbstractQueryResult

public AbstractQueryResult(Query query)

Constructor of the result from a Query.

Parameters:

query - The Query

Method Detail

disconnect

public void disconnect()

Method to disconnect the results from the ObjectManager, meaning that thereafter it just behaves like a List. All remaining results are read in at this point (unless selected not to be).

Specified by:

disconnect in interface QueryResult

closingConnection

protected abstract void closingConnection()

Inform the query result that the connection is being closed so perform any operations now, or rest in peace.

closeResults

protected abstract void closeResults()

Inform the query result that we are closing the results now.

close

public void close()

Method to close the results, meaning that they are inaccessible after this point.

Specified by:

close in interface QueryResult

addConnectionListener

public void addConnectionListener(ManagedConnectionResourceListener listener)

Method to register a listener to be notified when the query result is closing.

Parameters:

listener - The listener

isOpen

protected boolean isOpen()

Accessor whether the results are open.

Returns:

Whether it is open.

assertIsOpen

protected void assertIsOpen()

Internal method to throw an Exception if the ResultSet is open.

add

public void add(int index,
                java.lang.Object element)

Method to add a result. Unsupported.

Specified by:

add in interface java.util.List

Overrides:

add in class java.util.AbstractList

Parameters:

index - The position to add

element - The results to add

add

public boolean add(java.lang.Object o)

Method to add results. Unsupported.

Specified by:

add in interface java.util.Collection

Specified by:

add in interface java.util.List

Overrides:

add in class java.util.AbstractList

Parameters:

o - The result to add

Returns:

true if added successfully

addAll

public boolean addAll(int index,
                      java.util.Collection c)

Method to add results. Unsupported.

Specified by:

addAll in interface java.util.List

Overrides:

addAll in class java.util.AbstractList

Parameters:

index - The position to add

c - The results to add

Returns:

true if added successfully

clear

public void clear()

Method to clear the results.

Specified by:

clear in interface java.util.Collection

Specified by:

clear in interface java.util.List

Overrides:

clear in class java.util.AbstractList

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

Specified by:

contains in interface java.util.List

Overrides:

contains in class java.util.AbstractCollection

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

Specified by:

containsAll in interface java.util.List

Overrides:

containsAll in class java.util.AbstractCollection

Parameters:

c - The collection of objects

Returns:

Whether they are all contained here.

equals

public abstract boolean equals(java.lang.Object o)

Equality operator for QueryResults. Overrides the AbstractList implementation since that uses size() and iterator() and that would cause problems when closed.

Specified by:

equals in interface java.util.Collection

Specified by:

equals in interface java.util.List

Overrides:

equals in class java.util.AbstractList

Parameters:

o - The object to compare against

Returns:

Whether they are equal

get

public abstract java.lang.Object get(int index)

Method to retrieve a particular element from the list.

Specified by:

get in interface java.util.List

Specified by:

get in class java.util.AbstractList

Parameters:

index - The index of the element

Returns:

The element at index

hashCode

public int hashCode()

Accessor for the hashcode of this object

Specified by:

hashCode in interface java.util.Collection

Specified by:

hashCode in interface java.util.List

Overrides:

hashCode in class java.util.AbstractList

Returns:

The hash code

indexOf

public int indexOf(java.lang.Object o)

Method to check the index of a result. Not supported.

Specified by:

indexOf in interface java.util.List

Overrides:

indexOf in class java.util.AbstractList

Parameters:

o - The result

Returns:

The position

isEmpty

public boolean isEmpty()

Returns true if this collection contains no elements.

Specified by:

isEmpty in interface java.util.Collection

Specified by:

isEmpty in interface java.util.List

Overrides:

isEmpty in class java.util.AbstractCollection

Returns:

true if this collection contains no elements.

iterator

public abstract java.util.Iterator iterator()

Accessor for an iterator for the results.

Specified by:

iterator in interface java.lang.Iterable

Specified by:

iterator in interface java.util.Collection

Specified by:

iterator in interface java.util.List

Overrides:

iterator in class java.util.AbstractList

Returns:

The iterator

lastIndexOf

public int lastIndexOf(java.lang.Object o)

Method to check the last index of a result. Not supported.

Specified by:

lastIndexOf in interface java.util.List

Overrides:

lastIndexOf in class java.util.AbstractList

Parameters:

o - The result

Returns:

The last index

listIterator

public abstract java.util.ListIterator listIterator()

Accessor for a list iterator for the results.

Specified by:

listIterator in interface java.util.List

Overrides:

listIterator in class java.util.AbstractList

Returns:

a ListIterator with the query results

remove

public java.lang.Object remove(int index)

Method to remove a result. Not supported.

Specified by:

remove in interface java.util.List

Overrides:

remove in class java.util.AbstractList

Parameters:

index - The position of the result.

Returns:

The removed object.

set

public java.lang.Object set(int index,
                            java.lang.Object element)

Method to set the position of a result. Not supported.

Specified by:

set in interface java.util.List

Overrides:

set in class java.util.AbstractList

Parameters:

index - Position of the result

element - The result

Returns:

The element

size

public abstract int size()

Method to return the size of the result.

Specified by:

size in interface java.util.Collection

Specified by:

size in interface java.util.List

Specified by:

size in class java.util.AbstractCollection

Returns:

The size of the result.

subList

public java.util.List subList(int fromIndex,
                              int toIndex)

Method return a sub list of results. Method create new ArrayList, iterate and call get() in subclass for optimum perfomance.

Specified by:

subList in interface java.util.List

Overrides:

subList in class java.util.AbstractList

Parameters:

fromIndex - start position

toIndex - end position (exclusive)

Returns:

The list of results

toArray

public java.lang.Object[] toArray()

Method to return the results as an array.

Specified by:

toArray in interface java.util.Collection

Specified by:

toArray in interface java.util.List

Overrides:

toArray in class java.util.AbstractCollection

Returns:

The array.

toArray

public java.lang.Object[] toArray(java.lang.Object[] a)

Method to return the results as an array.

Specified by:

toArray in interface java.util.Collection

Specified by:

toArray in interface java.util.List

Overrides:

toArray in class java.util.AbstractCollection

Parameters:

a - The array to copy into.

Returns:

The array.