com.vaadin.data.util.filter
Class IsNull

java.lang.Object
  com.vaadin.data.util.filter.IsNull

All Implemented Interfaces:

Container.Filter, Serializable

public final class IsNull
extends Object
implements Container.Filter

Simple container filter checking whether an item property value is null. This filter also directly supports in-memory filtering.

Since:

6.6

See Also:

Serialized Form

Constructor Summary

IsNull(Object propertyId)
Constructor for a filter that compares the value of an item property with null.

Method Summary

boolean	appliesToProperty(Object propertyId) Check if a change in the value of a property can affect the filtering result.
boolean	equals(Object obj)
Object	getPropertyId() Returns the property id of the property tested by the filter, not null for valid filters.
int	hashCode()
boolean	passesFilter(Object itemId, Item item) Check if an item passes the filter (in-memory filtering).

Methods inherited from class java.lang.Object

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

Constructor Detail

IsNull

public IsNull(Object propertyId)

Constructor for a filter that compares the value of an item property with null. For in-memory filtering, a simple == check is performed. For other containers, the comparison implementation is container dependent but should correspond to the in-memory null check.

Parameters:

propertyId - the identifier (not null) of the property whose value to check

Method Detail

passesFilter

public boolean passesFilter(Object itemId,
                            Item item)
                     throws UnsupportedOperationException

Description copied from interface: Container.Filter

Check if an item passes the filter (in-memory filtering).

Specified by:

passesFilter in interface Container.Filter

Parameters:

itemId - identifier of the item being filtered; may be null when the item is being added to the container

item - the item being filtered

Returns:

true if the item is accepted by this filter

Throws:

UnsupportedOperationException - if the filter cannot be used for in-memory filtering

appliesToProperty

public boolean appliesToProperty(Object propertyId)

Description copied from interface: Container.Filter

Check if a change in the value of a property can affect the filtering result. May always return true, at the cost of performance. If the filter cannot determine whether it may depend on the property or not, should return true.

Specified by:

appliesToProperty in interface Container.Filter

Returns:

true if the filtering result may/does change based on changes to the property identified by propertyId

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

getPropertyId

public Object getPropertyId()

Returns the property id of the property tested by the filter, not null for valid filters.

Returns:

property id (not null)