# LogCursor (Oracle - Berkeley DB Java API)
Date: 2017-04-13

com.sleepycat.db

## Class LogCursor

- java.lang.Object
- - com.sleepycat.db.LogCursor

    public class LogCursor
    extends java.lang.Object

The LogCursor object is the handle for a cursor into the log files, supporting sequential access to the records stored in log files.

The handle is not free-threaded. Once the `LogCursor.close` method is called, the handle may not be accessed again, regardless of that method's success or failure.

### Method Summary

All Methods Instance Methods Concrete Methods
`void` `close()` Discard the log cursor.
`OperationStatus` `getCurrent(LogSequenceNumber lsn, DatabaseEntry data)` Return the LogSequenceNumber and log record to which the log cursor currently refers.
`OperationStatus` `getFirst(LogSequenceNumber lsn, DatabaseEntry data)` Return the first LogSequenceNumber and log record.
`OperationStatus` `getLast(LogSequenceNumber lsn, DatabaseEntry data)` Return the last LogSequenceNumber and log record.
`OperationStatus` `getNext(LogSequenceNumber lsn, DatabaseEntry data)` Return the next LogSequenceNumber and log record.
`OperationStatus` `getPrev(LogSequenceNumber lsn, DatabaseEntry data)` Return the previous LogSequenceNumber and log record.
`OperationStatus` `set(LogSequenceNumber lsn, DatabaseEntry data)` Return a specific log record.
`int` `version()` Get the log file version.

### Methods inherited from class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

### Method Detail

#### close

    public void close()
               throws DatabaseException

Discard the log cursor. After close() has been called, regardless of its return, the cursor handle may not be used again.

Throws:
  `DatabaseException` - if a failure occurs.

#### getCurrent

    public OperationStatus getCurrent(LogSequenceNumber lsn,
                                      DatabaseEntry data)
                               throws DatabaseException

Return the LogSequenceNumber and log record to which the log cursor currently refers.

Parameters:
  `lsn` - The returned LogSequenceNumber.

  `data` - The returned log record. The data field is set to the record retrieved, and the size field indicates the number of bytes in the record.

Returns:
  The status of the operation.

Throws:
  `DatabaseException` - if a failure occurs.

#### getNext

    public OperationStatus getNext(LogSequenceNumber lsn,
                                   DatabaseEntry data)
                            throws DatabaseException

Return the next LogSequenceNumber and log record.

The current log position is advanced to the next record in the log, and its LogSequenceNumber and data are returned. If the cursor has not been initialized, the first available log record in the log will be returned.

Parameters:
  `lsn` - The returned LogSequenceNumber.

  `data` - The returned log record.

Returns:
  The status of the operation; a return of NOTFOUND indicates the last log record has already been returned or the log is empty.

Throws:
  `DatabaseException` - if a failure occurs.

#### getFirst

    public OperationStatus getFirst(LogSequenceNumber lsn,
                                    DatabaseEntry data)
                             throws DatabaseException

Return the first LogSequenceNumber and log record.

The current log position is set to the first record in the log, and its LogSequenceNumber and data are returned.

Parameters:
  `lsn` - The returned LogSequenceNumber.

  `data` - The returned log record.

Returns:
  The status of the operation; a return of NOTFOUND indicates the log is empty.

Throws:
  `DatabaseException` - if a failure occurs.

#### getLast

    public OperationStatus getLast(LogSequenceNumber lsn,
                                   DatabaseEntry data)
                            throws DatabaseException

Return the last LogSequenceNumber and log record.

The current log position is set to the last record in the log, and its LogSequenceNumber and data are returned.

Parameters:
  `lsn` - The returned LogSequenceNumber.

  `data` - The returned log record.

Returns:
  The status of the operation; a return of NOTFOUND indicates the log is empty.

Throws:
  `DatabaseException` - if a failure occurs.

#### getPrev

    public OperationStatus getPrev(LogSequenceNumber lsn,
                                   DatabaseEntry data)
                            throws DatabaseException

Return the previous LogSequenceNumber and log record.

The current log position is advanced to the previous record in the log, and its LogSequenceNumber and data are returned. If the cursor has not been initialized, the last available log record in the log will be returned.

Parameters:
  `lsn` - The returned LogSequenceNumber.

  `data` - The returned log record.

Returns:
  The status of the operation; a return of NOTFOUND indicates the first log record has already been returned or the log is empty.

Throws:
  `DatabaseException` - if a failure occurs.

#### set

    public OperationStatus set(LogSequenceNumber lsn,
                               DatabaseEntry data)
                        throws DatabaseException

Return a specific log record.

The current log position is set to the specified record in the log, and its data is returned.

Parameters:
  `lsn` - The specified LogSequenceNumber.

  `data` - The returned log record.

Returns:
  The status of the operation.

Throws:
  `DatabaseException` - if a failure occurs.

#### version

    public int version()
                throws DatabaseException

Get the log file version.

Returns:
  The log file version.

Throws:
  `DatabaseException` - if a failure occurs.