IEMessageStore (eBus Feed 7.4.0 API)

All Known Implementing Classes:

InMemoryMessageStore, SqlMessageStore
```
public interface IEMessageStore
```
This interface provides EHistoricPublishFeed the ability to persist notification messages and to retrieve those message for a given historic time interval. Notification messages are persisted when an historic publisher publishes a notification message. Notification messages are retrieved when EHistoricPublishFeed receives a request for historic messages.
Please note that this message store is not only used to persist application notification messages but also PublishStatusEvent messages.

An IEMessageStore instance may be shared among multiple EHistoricPublishFeeds but the implementation is responsible for maintaining thread-safety.

When building an EHistoricPublishFeed, a non-null, open message store must be passed to EHistoricPublishFeed.Builder.messageStore(IEMessageStore). Failure to do so results in an exception. The appropriate opening and closing of the IEMessageStore is outside the scope of the historic publish feed and left up to the application. The restriction is that the message store must be opened prior to opening the historic publish feed and closed after closing the historic publish feed.

It is left up to the implementation to decide how messages are persisted or retrieved.

Author:

Charles W. Rapp

See Also:

EHistoricPublishFeed, EInterval

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`isOpen()`	Returns `true` if this message store is open and ready to store or retrieve notification messages.
`EMessageKey`	`key()`	Returns message key associated with message store.
`Collection<ENotificationMessage>`	`retrieve(EInterval interval)`	Retrieves historic messages as defined by given date/time interval.
`void`	`store(ENotificationMessage message)`	Persists given notification message to store.

- Method Detail
  - isOpen
```
boolean isOpen()
```
    Returns true if this message store is open and ready to store or retrieve notification messages.
    
    Returns:
    
    true if message store is open.
  - key
```
EMessageKey key()
```
    Returns message key associated with message store.
    
    Returns:
    
    message store's associated key.
  - store
```
void store(ENotificationMessage message)
```
    Persists given notification message to store.
    
    Parameters:
    
    message - persist this message.
    
    Throws:
    
    NullPointerException - if message is null.
    
    See Also:
    
    retrieve(EInterval)
  - retrieve
```
Collection<ENotificationMessage> retrieve(EInterval interval)
```
    Retrieves historic messages as defined by given date/time interval. Returned collection may be empty but never null.
    Please note that implementation are not required to validate interval since this is performed by EHistoricPublishFeed. That said, such validation is encourage if store is used outside of eBus historic feed framework.
    
    Parameters:
    
    interval - date/time interval.
    
    Returns:
    
    iterator over historic messages. Does not return null but may return iterator where Iterator.hasNext() returns false.
    
    See Also:
    
    store(ENotificationMessage)