DiskOrderedCursorImpl (starrocks-bdb-je 18.3.17 API)

```
public class DiskOrderedCursorImpl
extends Object
```
This class implements the DiskOrderedCursor. When an instance is constructed, a Producer Thread is created which runs a DiskOrderedScanner against the DiskOrderedCursor's Database. The callback for the DiskOrderedScanner takes key/data byte arrays that are passed to it, and then place those entries on a BlockingQueue which is shared between the Producer Thread and the application thread. When the application calls getNext(), it simply takes an entry off the queue and hands it to the caller. The entries on the queue are simple KeyAndData structs which hold byte[]'s for the key (and optional) data. A special instance of KeyAndData is used to indicate that the cursor scan has finished. The consistency guarantees are documented in the public javadoc for DiskOrderedCursor, and are based on the use of DiskOrderedScanner (see its javadoc for details). If the cleaner is operating concurrently with the DiskOrderedScanner, then it is possible for a file to be deleted and a not-yet-processed LSN (i.e. one which has not yet been returned to the user) might be pointing to that deleted file. Therefore, we must disable file deletion (but not cleaner operation) during the DOS.

Constructors
Constructor and Description
`DiskOrderedCursorImpl(DatabaseImpl[] dbImpls, DiskOrderedCursorConfig config)`

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`checkEnv()`
`void`	`close()`
`int`	`getCurrDb()`
`OperationResult`	`getCurrent(DatabaseEntry foundKey, DatabaseEntry foundData)`
`OperationResult`	`getNext(DatabaseEntry foundKey, DatabaseEntry foundData)`
`int`	`getNScannerIterations()` For testing and other internal use.
`boolean`	`isClosed()`
`boolean`	`isProcessorClosed()`

public DiskOrderedCursorImpl(DatabaseImpl[] dbImpls,
                             DiskOrderedCursorConfig config)

public OperationResult getCurrent(DatabaseEntry foundKey,
                                  DatabaseEntry foundData)

public OperationResult getNext(DatabaseEntry foundKey,
                               DatabaseEntry foundData)

getNScannerIterations
```
public int getNScannerIterations()
```
For testing and other internal use.

Class DiskOrderedCursorImpl