jdbm.htree
Class HTree

java.lang.Object
  jdbm.htree.HTree

public class HTree
extends Object

Persistent hashtable implementation for PageManager. Implemented as an H*Tree structure. WARNING! If this instance is used in a transactional context, it *must* be discarded after a rollback.

Author:

Alex Boisvert

Method Summary

static HTree	createInstance(RecordManager recman) Create a persistent hashtable.
Object	get(Object key) Returns the value which is associated with the given key.
long	getRecid() Get the record identifier used to load this hashtable.
FastIterator	keys() Returns an enumeration of the keys contained in this
static HTree	load(RecordManager recman, long root_recid) Load a persistent hashtable
void	put(Object key, Object value) Associates the specified value with the specified key.
void	remove(Object key) Remove the value which is associated with the given key.
FastIterator	values() Returns an enumeration of the values contained in this

Methods inherited from class java.lang.Object

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

Method Detail

createInstance

public static HTree createInstance(RecordManager recman)
                            throws IOException

Create a persistent hashtable.

Parameters:

recman - Record manager used for persistence.

Throws:

IOException

load

public static HTree load(RecordManager recman,
                         long root_recid)
                  throws IOException

Load a persistent hashtable

Parameters:

recman - RecordManager used to store the persistent hashtable

root_recid - Record id of the root directory of the HTree

Throws:

IOException

put

public void put(Object key,
                Object value)
         throws IOException

Associates the specified value with the specified key.

Parameters:

key - key with which the specified value is to be assocated.

value - value to be associated with the specified key.

Throws:

IOException

get

public Object get(Object key)
           throws IOException

Returns the value which is associated with the given key. Returns null if there is not association for this key.

Parameters:

key - key whose associated value is to be returned

Throws:

IOException

remove

public void remove(Object key)
            throws IOException

Remove the value which is associated with the given key. If the key does not exist, this method simply ignores the operation.

Parameters:

key - key whose associated value is to be removed

Throws:

IOException

keys

public FastIterator keys()
                  throws IOException

Returns an enumeration of the keys contained in this

Throws:

IOException

values

public FastIterator values()
                    throws IOException

Returns an enumeration of the values contained in this

Throws:

IOException

getRecid

public long getRecid()

Get the record identifier used to load this hashtable.