BitstreamDispatcher (DSpace Kernel :: API and Implementation 7.6.1 API)

All Known Implementing Classes:

HandleDispatcher, IteratorDispatcher, LimitedCountDispatcher, LimitedDurationDispatcher, SimpleDispatcher
```
public interface BitstreamDispatcher
```
BitstreamDispatchers are strategy objects that hand bitstream ids out to workers. Implementations must be threadsafe.

The rationale behind the use of the Sentinel pattern (rather than the more traditional iterator pattern or a cursor c.f. java.sql.ResultSet): -
1. To make it easy to make implementations thread safe - multithreaded invocation of the dispatchers is seen as a next step use case. In simple terms, this requires that a single method does all the work.
2. Shouldn't an exception as the sentinel, as reaching the end of a loop is not an exceptional condition.
Author:

Jim Downing, Grace Carpenter, Nathan Sarr

- Field Summary
  
  Fields
  Modifier and Type Field Description
  
  static int SENTINEL
  This value should be returned by next() to indicate that there are no more values.
- Method Summary
  
  All Methods Instance Methods Abstract Methods
  Modifier and Type Method Description
  
  Bitstream next()
  Returns the next id for checking, or a sentinel value if there are no more to check.

- Field Detail
  - SENTINEL
```
static final int SENTINEL
```
    This value should be returned by next() to indicate that there are no more values.
    
    See Also:
    
    Constant Field Values
- Method Detail
  - next
```
Bitstream next()
        throws SQLException
```
    Returns the next id for checking, or a sentinel value if there are no more to check.
    
    Returns:
    
    the next bitstream id, or BitstreamDispatcher.SENTINEL if there isn't another value
    
    Throws:
    
    SQLException - if database error