package com.vaadin.data.util.filter;
import com.vaadin.data.Container.Filter;
import com.vaadin.data.Item;
import com.vaadin.data.Property;
/**
* Simple container filter checking whether an item property value is null.
*
* This filter also directly supports in-memory filtering.
*
* @since 6.6
*/
public final class IsNull implements Filter {
private final 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.
*
* @param propertyId
* the identifier (not null) of the property whose value to check
*/
public IsNull(Object propertyId) {
this.propertyId = propertyId;
}
public boolean passesFilter(Object itemId, Item item)
throws UnsupportedOperationException {
final Property p = item.getItemProperty(getPropertyId());
if (null == p) {
return false;
}
return null == p.getValue();
}
public boolean appliesToProperty(Object propertyId) {
return getPropertyId().equals(propertyId);
}
@Override
public boolean equals(Object obj) {
// Only objects of the same class can be equal
if (!getClass().equals(obj.getClass())) {
return false;
}
final IsNull o = (IsNull) obj;
// Checks the properties one by one
return (null != getPropertyId()) ? getPropertyId().equals(
o.getPropertyId()) : null == o.getPropertyId();
}
@Override
public int hashCode() {
return (null != getPropertyId() ? getPropertyId().hashCode() : 0);
}
/**
* Returns the property id of the property tested by the filter, not null
* for valid filters.
*
* @return property id (not null)
*/
public Object getPropertyId() {
return propertyId;
}
}