Package com.sleepycat.db

Class Cursor

java.lang.Object

com.sleepycat.db.Cursor

Direct Known Subclasses:

SecondaryCursor

public class Cursor
extends java.lang.Object

A database cursor. Cursors are used for operating on collections of records, for iterating over a database, and for saving handles to individual records, so that they can be modified after they have been read.

Cursors may be used by multiple threads, but only serially. That is, the application must serialize access to the handle.

If the cursor is to be used to perform operations on behalf of a transaction, the cursor must be opened and closed within the context of that single transaction.

If you do not close the cursor before closing the database handle or the transaction handle that owns this cursor, then, closing a database handle or a transaction handle closes these open cursors. Once the cursor close method has been called, the handle may not be accessed again, regardless of the close method's success or failure.

To obtain a cursor with default attributes:

    Cursor cursor = myDatabase.openCursor(txn, null);

To customize the attributes of a cursor, use a CursorConfig object.

    CursorConfig config = new CursorConfig();
    config.setDirtyRead(true);
    Cursor cursor = myDatabase.openCursor(txn, config);

Modifications to the database during a sequential scan will be reflected in the scan; that is, records inserted behind a cursor will not be returned while records inserted in front of a cursor will be returned. In Queue and Recno databases, missing entries (that is, entries that were never explicitly created or that were created and then deleted) will be ignored during a sequential scan.

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Cursor(Database database, CursorConfig config)

Method Summary

Modifier and Type	Method	Description
void	close()	Discard the cursor.
int	compare(Cursor OtherCursor)	Return a comparison of the two cursors.
int	count()	Return a count of the number of data items for the key to which the cursor refers.
OperationStatus	delete()	Delete the key/data pair to which the cursor refers.
Cursor	dup(boolean samePosition)	Creates a new cursor that uses the same transaction and locker ID as the original cursor.
CursorConfig	getConfig()	Return this cursor's configuration.
OperationStatus	getCurrent(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Returns the key/data pair to which the cursor refers.
Database	getDatabase()	Return the Database handle associated with this Cursor.
OperationStatus	getFirst(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the first key/data pair of the database, and return that pair.
OperationStatus	getLast(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the last key/data pair of the database, and return that pair.
OperationStatus	getNext(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the next key/data pair and return that pair.
OperationStatus	getNextDup(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	If the next key/data pair of the database is a duplicate data record for the current key/data pair, move the cursor to the next key/data pair of the database and return that pair.
OperationStatus	getNextNoDup(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the next non-duplicate key/data pair and return that pair.
OperationStatus	getPrev(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the previous key/data pair and return that pair.
OperationStatus	getPrevDup(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	If the previous key/data pair of the database is a duplicate data record for the current key/data pair, move the cursor to the previous key/data pair of the database and return that pair.
OperationStatus	getPrevNoDup(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the previous non-duplicate key/data pair and return that pair.
CacheFilePriority	getPriority()	Get the cache priority for pages referenced by the cursor.
OperationStatus	getRecordNumber(DatabaseEntry data, LockMode lockMode)	Return the record number associated with the cursor.
OperationStatus	getSearchBoth(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the specified key/data pair, where both the key and data items must match.
OperationStatus	getSearchBothRange(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the specified key and matching data item of the database.
OperationStatus	getSearchKey(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the given key of the database, and return the datum associated with the given key.
OperationStatus	getSearchKeyRange(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the closest matching key of the database, and return the data item associated with the matching key.
OperationStatus	getSearchRecordNumber(DatabaseEntry key, DatabaseEntry data, LockMode lockMode)	Move the cursor to the specific numbered record of the database, and return the associated key/data pair.
DatabaseStream	openDatabaseStream(DatabaseStreamConfig config)	Return a database stream pointing to a key/data pair where the data item is an external file.
OperationStatus	put(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putAfter(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putBefore(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putCurrent(DatabaseEntry data)	Replaces the data in the key/data pair at the current cursor position.
OperationStatus	putKeyFirst(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putKeyLast(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putNoDupData(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
OperationStatus	putNoOverwrite(DatabaseEntry key, DatabaseEntry data)	Store a key/data pair into the database.
void	setPriority(CacheFilePriority priority)	Set the cache priority for pages referenced by the DBC handle.

Methods inherited from class java.lang.Object

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

Constructor Detail

Cursor

protected Cursor(Database database,
                 CursorConfig config)

Method Detail

close

public void close()
           throws DatabaseException

Discard the cursor.

After the close method has been called, you cannot use the cursor handle again.

It is not required to close the cursor explicitly before closing the database handle or the transaction handle that owns this cursor because closing a database handle or transaction handle closes those open cursor.

However, it is recommended that you always close all cursor handles immediately after their use to promote concurrency and to release resources such as page locks.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock. If the application is already intending to abort the transaction, this exception should be ignored, and the application should proceed.

DatabaseException - if a failure occurs.

dup

public Cursor dup(boolean samePosition)
           throws DatabaseException

Creates a new cursor that uses the same transaction and locker ID as the original cursor.

This is useful when an application is using locking and requires two or more cursors in the same thread of control.

Parameters:

samePosition - If true, the newly created cursor is initialized to refer to the same position in the database as the original cursor (if any) and hold the same locks (if any). If false, or the original cursor does not hold a database position and locks, the returned cursor is uninitialized and will behave like a newly created cursor.

Returns:

A new cursor with the same transaction and locker ID as the original cursor.

Throws:

DatabaseException - if a failure occurs.

getConfig

public CursorConfig getConfig()

Return this cursor's configuration.

This may differ from the configuration used to open this object if the cursor existed previously.

Returns:

This cursor's configuration.

getDatabase

public Database getDatabase()

Return the Database handle associated with this Cursor.

Returns:

The Database handle associated with this Cursor.

compare

public int compare(Cursor OtherCursor)
            throws DatabaseException

Return a comparison of the two cursors. Two cursors are equal if and only if they are positioned on the same item in the same database.

Parameters:

OtherCursor - the other cursor to be compared

Returns:

An integer representing the result of the comparison between this cursor and OtherCursor (another cursor handle used as the comparator). 0 indicates that this cursor and OtherCursor are positioned on the same item, 1 indicates this cursor is greater than OtherCursor, -1 indicates that OtherCursor is greater than this cursor.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

DatabaseException - if a failure occurs.

count

public int count()
          throws DatabaseException

Return a count of the number of data items for the key to which the cursor refers.

Returns:

A count of the number of data items for the key to which the cursor refers.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

DatabaseException - if a failure occurs.

delete

public OperationStatus delete()
                       throws DatabaseException

Delete the key/data pair to which the cursor refers.

When called on a cursor opened on a database that has been made into a secondary index, this method deletes the key/data pair from the primary database and all secondary indices.

The cursor position is unchanged after a delete, and subsequent calls to cursor functions expecting the cursor to refer to an existing key will fail.

Returns:

OperationStatus.KEYEMPTY if the key/pair at the cursor position has been deleted; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

DatabaseException - if a failure occurs.

getCurrent

public OperationStatus getCurrent(DatabaseEntry key,
                                  DatabaseEntry data,
                                  LockMode lockMode)
                           throws DatabaseException

Returns the key/data pair to which the cursor refers.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.KEYEMPTY if the key/pair at the cursor position has been deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getFirst

public OperationStatus getFirst(DatabaseEntry key,
                                DatabaseEntry data,
                                LockMode lockMode)
                         throws DatabaseException

Move the cursor to the first key/data pair of the database, and return that pair. If the first key has duplicate values, the first data item in the set of duplicates is returned.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getLast

public OperationStatus getLast(DatabaseEntry key,
                               DatabaseEntry data,
                               LockMode lockMode)
                        throws DatabaseException

Move the cursor to the last key/data pair of the database, and return that pair. If the last key has duplicate values, the last data item in the set of duplicates is returned.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getNext

public OperationStatus getNext(DatabaseEntry key,
                               DatabaseEntry data,
                               LockMode lockMode)
                        throws DatabaseException

Move the cursor to the next key/data pair and return that pair. If the matching key has duplicate values, the first data item in the set of duplicates is returned.

If the cursor is not yet initialized, move the cursor to the first key/data pair of the database, and return that pair. Otherwise, the cursor is moved to the next key/data pair of the database, and that pair is returned. In the presence of duplicate key values, the value of the key may not change.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getNextDup

public OperationStatus getNextDup(DatabaseEntry key,
                                  DatabaseEntry data,
                                  LockMode lockMode)
                           throws DatabaseException

If the next key/data pair of the database is a duplicate data record for the current key/data pair, move the cursor to the next key/data pair of the database and return that pair.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getNextNoDup

public OperationStatus getNextNoDup(DatabaseEntry key,
                                    DatabaseEntry data,
                                    LockMode lockMode)
                             throws DatabaseException

Move the cursor to the next non-duplicate key/data pair and return that pair. If the matching key has duplicate values, the first data item in the set of duplicates is returned.

If the cursor is not yet initialized, move the cursor to the first key/data pair of the database, and return that pair. Otherwise, the cursor is moved to the next non-duplicate key of the database, and that key/data pair is returned.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getPrev

public OperationStatus getPrev(DatabaseEntry key,
                               DatabaseEntry data,
                               LockMode lockMode)
                        throws DatabaseException

Move the cursor to the previous key/data pair and return that pair. If the matching key has duplicate values, the last data item in the set of duplicates is returned.

If the cursor is not yet initialized, move the cursor to the last key/data pair of the database, and return that pair. Otherwise, the cursor is moved to the previous key/data pair of the database, and that pair is returned. In the presence of duplicate key values, the value of the key may not change.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getPrevDup

public OperationStatus getPrevDup(DatabaseEntry key,
                                  DatabaseEntry data,
                                  LockMode lockMode)
                           throws DatabaseException

If the previous key/data pair of the database is a duplicate data record for the current key/data pair, move the cursor to the previous key/data pair of the database and return that pair.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getPrevNoDup

public OperationStatus getPrevNoDup(DatabaseEntry key,
                                    DatabaseEntry data,
                                    LockMode lockMode)
                             throws DatabaseException

Move the cursor to the previous non-duplicate key/data pair and return that pair. If the matching key has duplicate values, the last data item in the set of duplicates is returned.

If the cursor is not yet initialized, move the cursor to the last key/data pair of the database, and return that pair. Otherwise, the cursor is moved to the previous non-duplicate key of the database, and that key/data pair is returned.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getRecordNumber

public OperationStatus getRecordNumber(DatabaseEntry data,
                                       LockMode lockMode)
                                throws DatabaseException

Return the record number associated with the cursor. The record number will be returned in the data parameter.

For this method to be called, the underlying database must be of type Btree, and it must have been configured to support record numbers.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

data - the data returned as output. Its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getSearchKey

public OperationStatus getSearchKey(DatabaseEntry key,
                                    DatabaseEntry data,
                                    LockMode lockMode)
                             throws DatabaseException

Move the cursor to the given key of the database, and return the datum associated with the given key. If the matching key has duplicate values, the first data item in the set of duplicates is returned.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key used as input. It must be initialized with a non-null byte array by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getSearchKeyRange

public OperationStatus getSearchKeyRange(DatabaseEntry key,
                                         DatabaseEntry data,
                                         LockMode lockMode)
                                  throws DatabaseException

Move the cursor to the closest matching key of the database, and return the data item associated with the matching key. If the matching key has duplicate values, the first data item in the set of duplicates is returned.

The returned key/data pair is for the smallest key greater than or equal to the specified key (as determined by the key comparison function), permitting partial key matches and range searches.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key used as input and returned as output. It must be initialized with a non-null byte array by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getSearchBoth

public OperationStatus getSearchBoth(DatabaseEntry key,
                                     DatabaseEntry data,
                                     LockMode lockMode)
                              throws DatabaseException

Move the cursor to the specified key/data pair, where both the key and data items must match.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key used as input. It must be initialized with a non-null byte array by the caller.

data - the data used as input. It must be initialized with a non-null byte array by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getSearchBothRange

public OperationStatus getSearchBothRange(DatabaseEntry key,
                                          DatabaseEntry data,
                                          LockMode lockMode)
                                   throws DatabaseException

Move the cursor to the specified key and matching data item of the database.

In the case of any database supporting sorted duplicate sets, the returned key/data pair is for the smallest data item greater than or equal to the specified data item (as determined by the duplicate comparison function), permitting partial matches and range searches in duplicate data sets.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key used as input and returned as output. It must be initialized with a non-null byte array by the caller.

data - the data used as input and returned as output. It must be initialized with a non-null byte array by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

getSearchRecordNumber

public OperationStatus getSearchRecordNumber(DatabaseEntry key,
                                             DatabaseEntry data,
                                             LockMode lockMode)
                                      throws DatabaseException

Move the cursor to the specific numbered record of the database, and return the associated key/data pair.

The data field of the specified key must be a byte array containing a record number, as described in DatabaseEntry. This determines the record to be retrieved.

For this method to be called, the underlying database must be of type Btree, and it must have been configured to support record numbers.

If this method fails for any reason, the position of the cursor will be unchanged.

Parameters:

key - the key returned as output. Its byte array does not need to be initialized by the caller.

data - the data returned as output. Multiple results can be retrieved by passing an object that is a subclass of MultipleEntry, otherwise its byte array does not need to be initialized by the caller.

lockMode - the locking attributes; if null, default attributes are used.

Returns:

OperationStatus.NOTFOUND if no matching key/data pair is found; OperationStatus.KEYEMPTY if the database is a Queue or Recno database and the specified key exists, but was never explicitly created by the application or was later deleted; otherwise, OperationStatus.SUCCESS.

Throws:

java.lang.NullPointerException - if a DatabaseEntry parameter is null or does not contain a required non-null byte array.

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

put

public OperationStatus put(DatabaseEntry key,
                           DatabaseEntry data)
                    throws DatabaseException

Store a key/data pair into the database.

If the put method succeeds, the cursor is always positioned to refer to the newly inserted item. If the put method fails for any reason, the state of the cursor will be unchanged.

If the key already appears in the database and duplicates are supported, the new data value is inserted at the correct sorted location. If the key already appears in the database and duplicates are not supported, the existing key/data pair will be replaced.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.SUCCESS

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putAfter

public OperationStatus putAfter(DatabaseEntry key,
                                DatabaseEntry data)
                         throws DatabaseException

Store a key/data pair into the database.

If the putAfter method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putAfter method fails for any reason, the state of the cursor will be unchanged.

In the case of the Btree and Hash access methods, insert the data element as a duplicate element of the key to which the cursor refers. The new element appears immediately after the current cursor position. It is an error to call this method if the underlying Btree or Hash database does not support duplicate data items. The key parameter is ignored.

In the case of the Hash access method, the putAfter method will fail and throw an exception if the current cursor record has already been deleted.

In the case of the Recno access method, it is an error to call this method if the underlying Recno database was not configured to have mutable record numbers. A new key is created, all records after the inserted item are automatically renumbered, and the key of the new record is returned in the key parameter. The initial value of the key parameter is ignored.

The putAfter method may not be called for the Queue access method.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.NOTFOUND if the current cursor record has already been deleted and the underlying access method is Hash; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putBefore

public OperationStatus putBefore(DatabaseEntry key,
                                 DatabaseEntry data)
                          throws DatabaseException

Store a key/data pair into the database.

If the putBefore method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putBefore method fails for any reason, the state of the cursor will be unchanged.

In the case of the Btree and Hash access methods, insert the data element as a duplicate element of the key to which the cursor refers. The new element appears immediately before the current cursor position. It is an error to call this method if the underlying Btree or Hash database does not support duplicate data items. The key parameter is ignored.

In the case of the Hash access method, the putBefore method will fail and throw an exception if the current cursor record has already been deleted.

In the case of the Recno access method, it is an error to call this method if the underlying Recno database was not configured to have mutable record numbers. A new key is created, all records after the inserted item are automatically renumbered, and the key of the new record is returned in the key parameter. The initial value of the key parameter is ignored.

The putBefore method may not be called for the Queue access method.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.NOTFOUND if the current cursor record has already been deleted and the underlying access method is Hash; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putNoOverwrite

public OperationStatus putNoOverwrite(DatabaseEntry key,
                                      DatabaseEntry data)
                               throws DatabaseException

Store a key/data pair into the database.

If the putNoOverwrite method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putNoOverwrite method fails for any reason, the state of the cursor will be unchanged.

If the key already appears in the database, putNoOverwrite will return OperationStatus.KEYEXIST.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.KEYEXIST if a matching key/data pair already exists in the database; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putKeyFirst

public OperationStatus putKeyFirst(DatabaseEntry key,
                                   DatabaseEntry data)
                            throws DatabaseException

Store a key/data pair into the database.

If the putKeyFirst method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putKeyFirst method fails for any reason, the state of the cursor will be unchanged.

In the case of the Btree and Hash access methods, insert the specified key/data pair into the database.

If the underlying database supports duplicate data items, and if the key already exists in the database and a duplicate sort function has been specified, the inserted data item is added in its sorted location. If the key already exists in the database and no duplicate sort function has been specified, the inserted data item is added as the first of the data items for that key.

The putKeyFirst method may not be called for the Queue or Recno access methods.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.SUCCESS

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putKeyLast

public OperationStatus putKeyLast(DatabaseEntry key,
                                  DatabaseEntry data)
                           throws DatabaseException

Store a key/data pair into the database.

If the putKeyLast method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putKeyLast method fails for any reason, the state of the cursor will be unchanged.

In the case of the Btree and Hash access methods, insert the specified key/data pair into the database.

If the underlying database supports duplicate data items, and if the key already exists in the database and a duplicate sort function has been specified, the inserted data item is added in its sorted location. If the key already exists in the database and no duplicate sort function has been specified, the inserted data item is added as the last of the data items for that key.

The putKeyLast method may not be called for the Queue or Recno access methods.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.SUCCESS

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putNoDupData

public OperationStatus putNoDupData(DatabaseEntry key,
                                    DatabaseEntry data)
                             throws DatabaseException

Store a key/data pair into the database.

If the putNoDupData method succeeds, the cursor is always positioned to refer to the newly inserted item. If the putNoDupData method fails for any reason, the state of the cursor will be unchanged.

In the case of the Btree and Hash access methods, insert the specified key/data pair into the database, unless a key/data pair comparing equally to it already exists in the database. If a matching key/data pair already exists in the database, OperationStatus.KEYEXIST is returned.

This method may only be called if the underlying database has been configured to support sorted duplicate data items.

This method may not be called for the Queue or Recno access methods.

Parameters:

key - the key DatabaseEntry operated on.

data - the data DatabaseEntry stored.

Returns:

OperationStatus.KEYEXIST if a matching key/data pair already exists in the database; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - if an invalid parameter was specified.

DatabaseException - if a failure occurs.

putCurrent

public OperationStatus putCurrent(DatabaseEntry data)
                           throws DatabaseException

Replaces the data in the key/data pair at the current cursor position.

Whether the putCurrent method succeeds or fails for any reason, the state of the cursor will be unchanged.

Overwrite the data of the key/data pair to which the cursor refers with the specified data item. This method will return OperationStatus.NOTFOUND if the cursor currently refers to an already-deleted key/data pair.

For a database that does not support duplicates, the data may be changed by this method. If duplicates are supported, the data may be changed only if a custom partial comparator is configured and the comparator considers the old and new data to be equal (that is, the comparator returns zero). For more information on partial comparators see DatabaseConfig.setDuplicateComparator(java.util.Comparator).

If the old and new data are unequal according to the comparator, a DatabaseException is thrown. Changing the data in this case would change the sort order of the record, which would change the cursor position, and this is not allowed. To change the sort order of a record, delete it and then re-insert it.

Parameters:

data - the data DatabaseEntry stored.

Returns:

OperationStatus.NOTFOUND if the current cursor record has already been deleted; otherwise, OperationStatus.SUCCESS.

Throws:

DeadlockException - - if the operation was selected to resolve a deadlock.

java.lang.IllegalArgumentException - - if an invalid parameter was specified.

DatabaseException - - if the old and new data are not equal according to the configured duplicate comparator or default comparator, or if a failure occurs.

getPriority

public CacheFilePriority getPriority()
                              throws DatabaseException

Get the cache priority for pages referenced by the cursor.

This method may be called at any time during the life of the application.

Returns:

the cache priority for pages referenced by the cursor

Throws:

DatabaseException - if a failure occurs.

setPriority

public void setPriority(CacheFilePriority priority)
                 throws DatabaseException

Set the cache priority for pages referenced by the DBC handle.

The priority of a page biases the replacement algorithm to be more or less likely to discard a page when space is needed in the buffer pool. The bias is temporary, and pages will eventually be discarded if they are not referenced again. The setPriority method is only advisory, and does not guarantee pages will be treated in a specific way.

This method may be called at any time during the life of the application.

Parameters:

priority - the new cache priority

Throws:

DatabaseException - if a failure occurs.

openDatabaseStream

public DatabaseStream openDatabaseStream(DatabaseStreamConfig config)
                                  throws DatabaseException

Return a database stream pointing to a key/data pair where the data item is an external file.

Parameters:

config - The database stream attributes. If null, default attributes are used.

Returns:

A database stream.

Throws:

DatabaseException - if the data item is not an external file.