Package org.dellroad.stuff.vaadin7

Class VaadinSessionContainer<T extends VaadinSessionInfo>

java.lang.Object

com.vaadin.data.util.AbstractContainer

com.vaadin.data.util.AbstractInMemoryContainer<I,String,BackedItem<T>>

org.dellroad.stuff.vaadin7.AbstractSimpleContainer<I,T>

org.dellroad.stuff.vaadin7.SimpleKeyedContainer<T,T>

org.dellroad.stuff.vaadin7.SelfKeyedContainer<T>

org.dellroad.stuff.vaadin7.VaadinSessionContainer<T>

Type Parameters:

T - the type of the Java objects that back each Item in the container

All Implemented Interfaces:

Container, Container.Filterable, Container.Indexed, Container.ItemSetChangeNotifier, Container.Ordered, Container.SimpleFilterable, Container.Sortable, Serializable, Connectable, PropertyExtractor<T>

public abstract class VaadinSessionContainer<T extends VaadinSessionInfo>
extends SelfKeyedContainer<T>

Container containing active VaadinSessions.

This class is useful when you need to display sessions in your GUI, for example, a table showing all logged-in users. Due to the fact that each VaadinSession has its own lock, building such a container without race conditions and deadlocks is somewhat tricky. This class performs the locking required during updates and provides thread-safe update() and reload() methods. Information about active VaadinSessions comes from the session tracking feature of the SpringVaadinServlet.

By subclassing this class and VaadinSessionInfo, additional session-related properties, such as logged-in user, can be added to the container by annotating the VaadinSessionInfo subclass with @ProvidesProperty annotations.

Note the following:

• This class only works with configurations where Vaadin sessions are stored in memory, and the SpringVaadinServlet must be used and configured with init parameter SpringVaadinServlet.SESSION_TRACKING_PARAMETER set to true.
• The connect() and disconnect() methods must be invoked before and after (respectively) this container is used; typically these would be invoked in the Component.attach() and ClientConnector.detach() methods of a corresponding widget.
• Connected instances retain a strong reference to each VaadinSession therein. Therefore, to avoid leaking closed sessions, instances should be periodically reloaded.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class com.vaadin.data.util.AbstractInMemoryContainer

AbstractInMemoryContainer.BaseItemAddEvent, AbstractInMemoryContainer.BaseItemRemoveEvent

Nested classes/interfaces inherited from class com.vaadin.data.util.AbstractContainer

AbstractContainer.BaseItemSetChangeEvent, AbstractContainer.BasePropertySetChangeEvent

Nested classes/interfaces inherited from interface com.vaadin.data.Container

Container.Editor, Container.Filter, Container.Filterable, Container.Hierarchical, Container.Indexed, Container.ItemSetChangeEvent, Container.ItemSetChangeListener, Container.ItemSetChangeNotifier, Container.Ordered, Container.PropertySetChangeEvent, Container.PropertySetChangeListener, Container.PropertySetChangeNotifier, Container.SimpleFilterable, Container.Sortable, Container.Viewer

Nested classes/interfaces inherited from interface com.vaadin.data.Container.Indexed

Container.Indexed.ItemAddEvent, Container.Indexed.ItemRemoveEvent

Field Summary

Fields

Modifier and Type	Field	Description
protected VaadinSession	session	The VaadinSession that this container instance is associated with.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	VaadinSessionContainer(Class<T> type)	Constructor.
protected	VaadinSessionContainer(PropertyExtractor<? super T> propertyExtractor, Collection<? extends PropertyDef<?>> propertyDefs)	Constructor.

Method Summary

Modifier and Type	Method	Description
void	connect()	Connect this container and start tracking sessions.
protected abstract T	createVaadinSessionInfo()	Create a VaadinSessionInfo backing object for the VaadinSession associated with the current thread.
void	disconnect()	Disconnect this container and stop tracking sessions.
protected void	doReload()	Reload this container.
protected void	doUpdate()	Update each VaadinSessionInfo instance in this container.
void	reload()	Asynchronously reload this container.
void	update()	Asynchronously update this container's items.

Methods inherited from class org.dellroad.stuff.vaadin7.SelfKeyedContainer

getKeyFor

Methods inherited from class org.dellroad.stuff.vaadin7.SimpleKeyedContainer

generateItemId, getItemIdFor, getItemIdForSame, getJavaObject, resetItemIds

Methods inherited from class org.dellroad.stuff.vaadin7.AbstractSimpleContainer

addContainerFilter, addContainerFilter, afterReload, createBackedItem, getContainerFilters, getContainerProperty, getContainerPropertyIds, getItemIds, getPropertyExtractor, getPropertyValue, getSortableContainerPropertyIds, getType, getUnfilteredItem, internalRemoveAllItems, load, load, removeAllContainerFilters, removeContainerFilter, removeContainerFilters, setProperties, setProperty, setPropertyExtractor, sort

Methods inherited from class com.vaadin.data.util.AbstractInMemoryContainer

addContainerProperty, addFilter, addItem, addItem, addItemAfter, addItemAfter, addItemAt, addItemAt, addItemSetChangeListener, addListener, containsId, doFilterContainer, doSort, filterAll, fireItemAdded, fireItemRemoved, fireItemsAdded, fireItemsRemoved, firstItemId, getAllItemIds, getFilteredItemIds, getFilters, getFirstVisibleItem, getIdByIndex, getItem, getItemIds, getItemSorter, getSortablePropertyIds, getVisibleItemIds, hasContainerFilters, indexOfId, internalAddItemAfter, internalAddItemAt, internalAddItemAtEnd, internalRemoveItem, isFiltered, isFirstId, isLastId, isPropertyFiltered, lastItemId, nextItemId, passesFilters, prevItemId, registerNewItem, removeAllFilters, removeAllItems, removeContainerProperty, removeFilter, removeFilters, removeItem, removeItemSetChangeListener, removeListener, setAllItemIds, setFilteredItemIds, setFilters, setItemSorter, size, sortContainer

Methods inherited from class com.vaadin.data.util.AbstractContainer

addListener, addPropertySetChangeListener, fireContainerPropertySetChange, fireContainerPropertySetChange, fireItemSetChange, fireItemSetChange, getItemSetChangeListeners, getListeners, getPropertySetChangeListeners, removeListener, removePropertySetChangeListener, setItemSetChangeListeners, setPropertySetChangeListeners

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.vaadin.data.Container

addContainerProperty, addItem, addItem, containsId, getItem, removeAllItems, removeContainerProperty, removeItem, size

Methods inherited from interface com.vaadin.data.Container.Ordered

addItemAfter, addItemAfter, firstItemId, isFirstId, isLastId, lastItemId, nextItemId, prevItemId

Field Detail

session

protected final VaadinSession session

The VaadinSession that this container instance is associated with. Determined by whatever VaadinSession is associated with the current thread at construction time.

Constructor Detail

VaadinSessionContainer

protected VaadinSessionContainer(Class<T> type)

Constructor.

Properties will be determined by the @ProvidesProperty and @ProvidesPropertySort annotated methods in the given class.

Parameters:

type - class to introspect for annotated methods

Throws:

IllegalArgumentException - if type is null

IllegalArgumentException - if type has two @ProvidesProperty or @ProvidesPropertySort annotated methods for the same property

IllegalArgumentException - if a @ProvidesProperty-annotated method with no property name specified has a name which cannot be interpreted as a bean property "getter" method

IllegalStateException - if there is no VaadinSession associated with the current thread

IllegalStateException - if there is no SpringVaadinServlet associated with the current thread's VaadinSession

See Also:

ProvidesProperty, ProvidesPropertySort, ProvidesPropertyScanner

VaadinSessionContainer

protected VaadinSessionContainer(PropertyExtractor<? super T> propertyExtractor,
                                 Collection<? extends PropertyDef<?>> propertyDefs)

Constructor.

Parameters:

propertyExtractor - used to extract properties from the underlying Java objects; may be null but then container is not usable until one is configured via setPropertyExtractor()

propertyDefs - container property definitions; null is treated like the empty set

Method Detail

connect

public void connect()

Connect this container and start tracking sessions.

Specified by:

connect in interface Connectable

Overrides:

connect in class AbstractSimpleContainer<T extends VaadinSessionInfo,T extends VaadinSessionInfo>

disconnect

public void disconnect()

Disconnect this container and stop tracking sessions.

Specified by:

disconnect in interface Connectable

Overrides:

disconnect in class AbstractSimpleContainer<T extends VaadinSessionInfo,T extends VaadinSessionInfo>

reload

public void reload()

Asynchronously reload this container.

This method can be invoked from any thread. It creates a new thread to do the actual reloading via doReload() to avoid potential deadlocks.

update

public void update()

Asynchronously update this container's items.

This method can be invoked from any thread. It creates a new thread to do the actual updating via doUpdate() to avoid potential deadlocks.

doUpdate

protected void doUpdate()

Update each VaadinSessionInfo instance in this container. Using this method is more efficient than reloading the entire container.

This method handles the complicated locking required to avoid deadlocks: first, for each VaadinSessionInfo, VaadinSessionInfo.updateInformation() is invoked while the VaadinSession corresponding to that VaadinSessionInfo instance is locked, so that information from that session can be safely gathered; then, VaadinSessionInfo.makeUpdatesVisible() is invoked while the VaadinSession associated with this container is locked, so item properties can be safely updated, etc.

This method must not be invoked while any VaadinSession is locked. For example, it may be invoked by a regular timer (only while this container is connected).

Throws:

IllegalStateException - if there is a locked VaadinSession associated with the current thread

doReload

protected void doReload()

Reload this container. Reloads this container with VaadinSessionInfo instances for each VaadinSession (created via createVaadinSessionInfo()), and then invokes doUpdate().

This method must not be invoked while any VaadinSession is locked.

Throws:

IllegalStateException - if there is a locked VaadinSession associated with the current thread

createVaadinSessionInfo

protected abstract T createVaadinSessionInfo()

Create a VaadinSessionInfo backing object for the VaadinSession associated with the current thread. The VaadinSession will be already locked.

Returns:

VaadinSessionInfo backing object for the current session