com.espertech.esper.event
Interface EventPropertyGetter

All Known Subinterfaces:
TypedEventPropertyGetter
All Known Implementing Classes:
ArrayFastPropertyGetter, ArrayFieldPropertyGetter, ArrayMethodPropertyGetter, CGLibPropertyGetter, DynamicIndexedPropertyGetter, DynamicMappedPropertyGetter, DynamicPropertyGetterBase, DynamicSimplePropertyGetter, KeyedFastPropertyGetter, KeyedMethodPropertyGetter, MapEventPropertyGetter, MapIndexedPropertyGetter, MapMappedPropertyGetter, MapNestedEventPropertyGetter, MapNestedPropertyGetter, MapPOJOEntryPropertyGetter, MapPropertyGetter, NestedPropertyGetter, ReflectionPropFieldGetter, ReflectionPropMethodGetter, XPathPropertyGetter

public interface EventPropertyGetter

Get property values from an event instance for a given event property. Instances that implement this interface are usually bound to a particular EventType and cannot be used to access EventBean instances of a different type.


Method Summary
 Object get(EventBean eventBean)
          Return the value for the property in the event object specified when the instance was obtained.
 boolean isExistsProperty(EventBean eventBean)
          Returns true if the property exists, or false if the type does not have such a property.
 

Method Detail

get

Object get(EventBean eventBean)
           throws PropertyAccessException
Return the value for the property in the event object specified when the instance was obtained. Useful for fast access to event properties. Throws a PropertyAccessException if the getter instance doesn't match the EventType it was obtained from, and to indicate other property access problems.

Parameters:
eventBean - is the event to get the value of a property from
Returns:
value of property in event
Throws:
PropertyAccessException - to indicate that property access failed

isExistsProperty

boolean isExistsProperty(EventBean eventBean)
Returns true if the property exists, or false if the type does not have such a property.

Useful for dynamic properties of the syntax "property?" and the dynamic nested/indexed/mapped versions. Dynamic nested properties follow the syntax "property?.nested" which is equivalent to "property?.nested?". If any of the properties in the path of a dynamic nested property return null, the dynamic nested property does not exists and the method returns false.

For non-dynamic properties, this method always returns true since a getter would not be available unless

Parameters:
eventBean - is the event to check if the dynamic property exists
Returns:
indictor whether the property exists, always true for non-dynamic (default) properties

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