This XML Schema document has N sections: 0 Defines types for generic data (e.g. time) 1 Defines types for the Event discovery 2 Defines types for the Notifications syntax 3 Defines types for Notification exchanges 4 Defines types for the subscription mechanism This is a union type to represent an EventSelectorType. It could be: * A single URI to match a single event type * A string represting a regular expression to match event types * The tokent 'all' to match all the known event types at the producer. An element of type EventTypeDefinitionListType contains zero or more child elements of type EventTypeDefinition. An element of type EventInstanceInfoListType contains zero or more child elements of type EventInstanceInfo. This is the root element that encapsulates zero, one or more Notification. It is used in the WS-Events WSDL to define the part of messages which carry notifications.There are no constraints on how the Notification elements are grouped in a NotificationList. For instance, a NotificationList can contain Notification elements of various types or from different sources. This element contains the URL of the event producer. The URL SHOULD be a valid network address even though it MAY not always be dereferencable because of network connectivity issues (e.g firewall). The notification source URL MAY be different from the one of the sender of the notification if, for instance, there is a broker acting as an intermediary between the event producer and consumer. However, the URL Source element SHOULD be the same than the one used in a subscribe call. Describes the type of the notification. Wildcard are not allowed. The date and time that uniquely identify the instant when the notification was created. This time should be equal to the event or events time that generated this notification. An optional element to indicate how long the notification is valid for. Events happen at a single point in time but notification can last longer since they are a physical representation of the event that propagates through systems. A system SHOULD not propagate any notification that have expired though the mechanisms described in this specification. However, for audit and logging purpose, it is expected that expired notifications will be transmistted using the apropriate means. If ExpiresOn is present, the value should be bigger or equal to the one in Timestamp. The Notification element is the basic building block used to convey information about events. It contains the minimal set of information to sustain the subscription protocal and ensure scalability. It is very generic and extensible. The optional Id attribute can be used to uniquely identify the notification in the list. To uniquely identify a notification, the concatenation of the content of the Source, Type and Timestamp can be used. If ExpiresOn is present, the value should be bigger or equal to the one in Timestamp.