to.etc.webapp.query

Class QAbstractDataContext

java.lang.Object

to.etc.webapp.query.QAbstractDataContext

All Implemented Interfaces:

AutoCloseable, QDataContext

public abstract class QAbstractDataContext
extends Object
implements QDataContext

A QDataContext proxy which allows queries to be sent to multiple rendering/selecting implementations. It delegates all query handling to the appropriate query handler.

Author:

Frits Jalvingh Created on Apr 29, 2010

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	QAbstractDataContext(QDataContextFactory contextFactory)

Method Summary

Modifier and Type	Method and Description
void	addListener(IQDataContextListener qDataContextListener) Add a listener to keep track of the events on an instance.
void	attach(Object o) If the object was from an earlier database session reattach it to another, live session.
void	delete(Object o) Cause the object to be deleted from the database.
<T> T	find(Class<T> clz, Object pk) Load the persistent object with the specified type and primary key from the database.
<T> T	find(ICriteriaTableDef<T> metatable, Object pk)
<T> T	get(Class<T> clz, Object pk) Load the persistent object with the specified type and primary key from the database.
QDataContextFactory	getFactory() Returns the context source which created this DataContext.
protected QQueryExecutorRegistry	getHandlerFactory()
<T> T	getInstance(Class<T> clz, Object pk) Load the persistent object with the specified type and primary key from the database.
<T> T	getInstance(ICriteriaTableDef<T> metatable, Object pk)
<R> List<R>	query(Class<R> resultInterface, QSelection<?> sel) Query a selection, and return the result in the specified proxied interface.
<T> List<T>	query(QCriteria<T> q) Execute the query specified by q and return a list of results.
List<Object[]>	query(QSelection<?> sel) Issue a selection query, where multiple fields or projections on fields are selected from a base class.
<R> R	queryOne(Class<R> resultInterface, QSelection<?> sel) Query a selection, and return the result in the specified proxied interface.
<T> T	queryOne(QCriteria<T> q) Execute the query specified by q, and expect and return at most 1 result.
Object[]	queryOne(QSelection<?> sel) Execute the selection query specified by q, and expect and return at most 1 result.
void	refresh(Object o) EXPERIMENTAL/NOT FINAL Refresh with latest content in the database.
void	save(Object o) Cause the object to be inserted in the database.

Methods inherited from class java.lang.Object

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

Methods inherited from interface to.etc.webapp.query.QDataContext

addCommitAction, close, commit, getConnection, inTransaction, original, rollback, setIgnoreClose, setKeepOriginals, startTransaction

Constructor Detail

QAbstractDataContext

protected QAbstractDataContext(QDataContextFactory contextFactory)

Method Detail

getHandlerFactory

protected QQueryExecutorRegistry getHandlerFactory()

getFactory

@Nonnull
public QDataContextFactory getFactory()

Returns the context source which created this DataContext. This context source is used to get query listeners to execute when a query is done.

Specified by:

getFactory in interface QDataContext

Returns:

find

public <T> T find(@Nonnull
                  Class<T> clz,
                  @Nonnull
                  Object pk)
           throws Exception

Load the persistent object with the specified type and primary key from the database. This will execute an actual select in the database if the object is not yet cached, ensuring that the object actually exists. If the object does not exist this will return null.

Specified by:

find in interface QDataContext

Type Parameters:

T - The object type.

Parameters:

clz - The persistent class for which an instance is being sought.

pk - The PK for the instance required.

Returns:

Null if the instance does not exist, the actual and fully initialized instance (or proxy) otherwise.

Throws:

Exception

See Also:

QDataContext.find(java.lang.Class, java.lang.Object)

get

@Nonnull
public <T> T get(@Nonnull
                          Class<T> clz,
                          @Nonnull
                          Object pk)
                   throws Exception

Load the persistent object with the specified type and primary key from the database. This will execute an actual select in the database if the object is not yet cached, ensuring that the object actually exists. If the object does not exist this will raise QNotFoundException.

Specified by:

get in interface QDataContext

Type Parameters:

T - The object type.

Parameters:

clz - The persistent class for which an instance is being sought.

pk - The PK for the instance required.

Returns:

The actual and fully initialized instance (or proxy).

Throws:

Exception

See Also:

QDataContext.get(java.lang.Class, java.lang.Object)

find

public <T> T find(@Nonnull
                  ICriteriaTableDef<T> metatable,
                  @Nonnull
                  Object pk)
           throws Exception

Specified by:

find in interface QDataContext

Throws:

Exception

getInstance

@Nonnull
public <T> T getInstance(@Nonnull
                                  Class<T> clz,
                                  @Nonnull
                                  Object pk)
                           throws Exception

Load the persistent object with the specified type and primary key from the database. This will return an object always even if the object does not exist in the database! This should only be used when you need an instance representing a given primary key that you know exists. This usually returns a proxy, meaning that nonexistent objects will throw exceptions as soon as properties other than it's primary key are accessed. To get an object and be sure it is present in the database use QDataContext.find(Class, Object).

Specified by:

getInstance in interface QDataContext

Type Parameters:

T - The object type

Parameters:

clz - The persistent class for which an instance is being sought.

pk - The PK for the instance required.

Returns:

Always returns an instance; it can be invalid when it does not really exist on the backing store.

Throws:

Exception

See Also:

QDataContext.getInstance(java.lang.Class, java.lang.Object)

getInstance

@Nonnull
public <T> T getInstance(@Nonnull
                                  ICriteriaTableDef<T> metatable,
                                  @Nonnull
                                  Object pk)
                           throws Exception

Specified by:

getInstance in interface QDataContext

Throws:

Exception

query

@Nonnull
public <T> List<T> query(@Nonnull
                                  QCriteria<T> q)
                           throws Exception

Execute the query specified by q and return a list of results. Before and after the query execution all registered listeners will be called.

Specified by:

query in interface QDataContext

Type Parameters:

T - The return type for this query, a persistent class type

Parameters:

q - The selection criteria

Returns:

Throws:

Exception

See Also:

QDataContext.query(to.etc.webapp.query.QCriteria)

query

@Nonnull
public List<Object[]> query(@Nonnull
                                     QSelection<?> sel)
                              throws Exception

Issue a selection query, where multiple fields or projections on fields are selected from a base class. This overrides the behaviour of Hibernate where a single-column selection does not return an array but that single object, for consistency's sake. It is slightly more expensive because an Object[1] is needed for every row, but compared with the heaps of memory Hibernate is already wasting this is peanuts.

Specified by:

query in interface QDataContext

Returns:

Throws:

Exception

See Also:

QDataContext.query(to.etc.webapp.query.QSelection)

query

@Nonnull
public <R> List<R> query(@Nonnull
                                  Class<R> resultInterface,
                                  @Nonnull
                                  QSelection<?> sel)
                           throws Exception

Description copied from interface: QDataContext

Query a selection, and return the result in the specified proxied interface. Members in the interface must be annotated with QFld annotations to define the order in the result set.

Specified by:

query in interface QDataContext

Returns:

Throws:

Exception

queryOne

@Nullable
public <R> R queryOne(@Nonnull
                                Class<R> resultInterface,
                                @Nonnull
                                QSelection<?> sel)
                         throws Exception

Description copied from interface: QDataContext

Query a selection, and return the result in the specified proxied interface. Members in the interface must be annotated with QFld annotations to define the order in the result set.

Specified by:

queryOne in interface QDataContext

Returns:

Throws:

Exception

queryOne

public <T> T queryOne(@Nonnull
                      QCriteria<T> q)
               throws Exception

Execute the query specified by q, and expect and return at most 1 result. If the query has no result this will return null. If more than one result is obtained this will throw an IllegalStateException.

Specified by:

queryOne in interface QDataContext

Returns:

Throws:

Exception

See Also:

QDataContext.queryOne(to.etc.webapp.query.QCriteria)

queryOne

public Object[] queryOne(@Nonnull
                         QSelection<?> sel)
                  throws Exception

Execute the selection query specified by q, and expect and return at most 1 result. If the query has no result this will return null. If more than one result is obtained this will throw an IllegalStateException.

Specified by:

queryOne in interface QDataContext

Returns:

Throws:

Exception

See Also:

QDataContext.queryOne(to.etc.webapp.query.QCriteria)

attach

public void attach(@Nonnull
                   Object o)
            throws Exception

If the object was from an earlier database session reattach it to another, live session.

Specified by:

attach in interface QDataContext

Throws:

Exception

See Also:

QDataContext.attach(java.lang.Object)

delete

public void delete(@Nonnull
                   Object o)
            throws Exception

Cause the object to be deleted from the database.

Specified by:

delete in interface QDataContext

Throws:

Exception

See Also:

QDataContext.delete(java.lang.Object)

save

public void save(@Nonnull
                 Object o)
          throws Exception

Cause the object to be inserted in the database.

Specified by:

save in interface QDataContext

Throws:

Exception

See Also:

QDataContext.save(java.lang.Object)

refresh

public void refresh(@Nonnull
                    Object o)
             throws Exception

EXPERIMENTAL/NOT FINAL Refresh with latest content in the database.

Specified by:

refresh in interface QDataContext

Throws:

Exception

See Also:

QDataContext.refresh(java.lang.Object)

addListener

public void addListener(@Nonnull
                        IQDataContextListener qDataContextListener)

Add a listener to keep track of the events on an instance.

Specified by:

addListener in interface QDataContext

See Also:

QDataContext.addListener(to.etc.webapp.query.IQDataContextListener)