com.goldencode.p2j.persist

Class AdaptiveQuery.DynamicResults

java.lang.Object

com.goldencode.p2j.persist.AdaptiveQuery.DynamicResults

All Implemented Interfaces:

Results

Enclosing class:

AdaptiveQuery

private class AdaptiveQuery.DynamicResults
extends java.lang.Object
implements Results

An implementation of the Results interface which uses a single table or multi-table DynamicQuery as a delegate. An instance of this method replaces the enclosing query's preselected results when a DMO state change invalidates those results. If a single table must be accessed, a modified RandomAccessQuery is used as a delegate. For multiple tables, a CompoundQuery is used.

The adaptive query's original query components are interrogated for their properties in order to create the dynamic query (and its components in the multi-table case).

Field Summary

Fields

Modifier and Type	Field and Description
private RecordBuffer[]	buffers All buffers being updated by the dynamic query
private boolean	closed Flag indicating this results object has been closed
private boolean[]	idOnly ID-only flags, ordered by column
private DynamicQuery	query Underlying query which manages the navigation of results

Fields inherited from interface com.goldencode.p2j.persist.Results

LOG

Constructor Summary

Constructors

Constructor and Description
DynamicResults(DynamicQuery query, boolean[] idOnly) Constructor which accepts a backing, dynamic query and turns scrolling on for that query.

Method Summary

Modifier and Type	Method and Description
void	cleanup() Clean up and release any resources which this object is holding, such as open result sets.
boolean	first() Move cursor to the first results row.
java.lang.Object[]	get() Get the array of objects at the current result row.
java.lang.Object	get(int column) Get the object at the current result row, at the specified column.
java.lang.Long	getID(int column) Get the primary key ID at the current result row, at the specified column.
int	getRowNumber() Get the row number currently under the cursor.
boolean	isAutoFetch() Is the result delegate responsible for fetching? This is usually true when using query delegates which handle the fetching process already.
boolean	isFirst() Is the cursor on the first row in the results set?
boolean	isLast() Is the cursor on the last row in the results set?
boolean	last() Move cursor to the last results row.
boolean	next() Move cursor to the next results row.
private boolean	postFetch(boolean revalidate) Optionally switch the enclosing back to preselect mode if possible and provide a return value which indicates whether the results object currently is positioned on a row.
boolean	previous() Move cursor to the previous results row.
private void	reposition(int row) Reposition the backing query to the given row.
void	reset() Reset the cursor to its natural starting position, before the first result row.
boolean	scroll(int rows) Scroll the cursor ahead by the specified number of rows.
void	sessionClosing() Invoked when the current Hibernate session is about to close.
boolean	setRowNumber(int row) Set the row number currently under the cursor.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.goldencode.p2j.persist.Results

addRow, deleteRow, get, getNumberOfLoadedRows, isResultSetCached

Field Detail

query

private final DynamicQuery query

Underlying query which manages the navigation of results

buffers

private final RecordBuffer[] buffers

All buffers being updated by the dynamic query

idOnly

private final boolean[] idOnly

ID-only flags, ordered by column

closed

private boolean closed

Flag indicating this results object has been closed

Constructor Detail

DynamicResults

DynamicResults(DynamicQuery query,
               boolean[] idOnly)
        throws PersistenceException

Constructor which accepts a backing, dynamic query and turns scrolling on for that query.

Parameters:

query - Dynamic query which will back this results object.

idOnly - Array of ID only flags, ordered by column.

Throws:

PersistenceException - if there is an error beginning a new transaction.

Method Detail

first

public boolean first()

Move cursor to the first results row.

Specified by:

first in interface Results

Returns:

true if there are any results.

last

public boolean last()

Move cursor to the last results row.

Specified by:

last in interface Results

Returns:

true if there are any results.

next

public boolean next()

Move cursor to the next results row.

Specified by:

next in interface Results

Returns:

true if there is a result under the cursor after the move.

previous

public boolean previous()

Move cursor to the previous results row.

Specified by:

previous in interface Results

Returns:

true if there is a result under the cursor after the move.

isFirst

public boolean isFirst()

Is the cursor on the first row in the results set?

Specified by:

isFirst in interface Results

Returns:

true if the cursor is on the first row.

isLast

public boolean isLast()

Is the cursor on the last row in the results set?

Specified by:

isLast in interface Results

Returns:

true if the cursor is on the last row.

isAutoFetch

public boolean isAutoFetch()

Is the result delegate responsible for fetching? This is usually true when using query delegates which handle the fetching process already.

Specified by:

isAutoFetch in interface Results

Returns:

true for complex results which also do the fetching

get

public java.lang.Object[] get()

Get the array of objects at the current result row.

Specified by:

get in interface Results

Returns:

Object array or null.

get

public java.lang.Object get(int column)

Get the object at the current result row, at the specified column.

Specified by:

get in interface Results

Parameters:

column - Zero-based index column of the desired object.

Returns:

Object at column or null.

getID

public java.lang.Long getID(int column)

Get the primary key ID at the current result row, at the specified column.

Specified by:

getID in interface Results

Parameters:

column - Zero-based index column of the desired ID.

Returns:

ID of the record or null.

getRowNumber

public int getRowNumber()

Get the row number currently under the cursor.

Specified by:

getRowNumber in interface Results

Returns:

Zero-based index of the current row, or 0 by default if the cursor's position is not currently known.

setRowNumber

public boolean setRowNumber(int row)

Set the row number currently under the cursor.

Specified by:

setRowNumber in interface Results

Parameters:

row - Zero-based index of the row to be set as the current row.

Returns:

true if there is a row at the specified row number; else false.

scroll

public boolean scroll(int rows)

Scroll the cursor ahead by the specified number of rows. If the number is negative, the cursor is moved backward. This may put the cursor off the end (either end) of the query's results.

Specified by:

scroll in interface Results

Parameters:

rows - Number of rows to jump ahead or back.

Returns:

true if there is a row at the new location; else false.

reset

public void reset()

Reset the cursor to its natural starting position, before the first result row.

Specified by:

reset in interface Results

sessionClosing

public void sessionClosing()

Invoked when the current Hibernate session is about to close. Gives the implementation an opportunity to perform appropriate processing in response to this event.

Specified by:

sessionClosing in interface Results

cleanup

public void cleanup()

Clean up and release any resources which this object is holding, such as open result sets.

Specified by:

cleanup in interface Results

reposition

private void reposition(int row)

Reposition the backing query to the given row. This method sets the fetch-on-reposition strategy of the backing query to that of the enclosing query before attempting the reposition.

Parameters:

row - Zero-based index of the target row.

postFetch

private boolean postFetch(boolean revalidate)

Optionally switch the enclosing back to preselect mode if possible and provide a return value which indicates whether the results object currently is positioned on a row.

Parameters:

revalidate - true if query should attempt to switch back to preselect mode, else false. The switch should only be made if the last operation moved forward through the query's results.

Returns:

true if positioned on a row, else false if off-end.