org.garret.perst
Interface BitIndex

All Superinterfaces:

java.io.Externalizable, IPersistent, IResource, ITable, java.io.Serializable

public interface BitIndex

extends IPersistent, IResource, ITable

Interface of bit index. Bit index allows to effiicently search object with specified set of properties. Each object has associated mask of 32 bites. Meaning of bits is application dependent. Usually each bit stands for some binary or boolean property, for example "sex", but it is possible to use group of bits to represent enumerations with more possible values.

Method Summary

void	clear() Remove all objects from the index
int	get(IPersistent obj) Get properties of specified object
java.util.Iterator	iterator() Get iterator through all objects in the index This iterator doesn't support remove() method.
java.util.Iterator	iterator(int set, int clear) Get iterator for selecting objects with specified properties.
void	put(IPersistent obj, int mask) Put new object in the index.
void	remove(IPersistent obj) Remove object from the index
int	size() Get number of objects in the index

Methods inherited from interface org.garret.perst.IPersistent

assignOid, deallocate, getOid, getStorage, invalidate, isDeleted, isModified, isPersistent, isRaw, load, loadAndModify, makePersistent, modify, onLoad, onStore, recursiveLoading, store

Methods inherited from interface java.io.Externalizable

readExternal, writeExternal

Methods inherited from interface org.garret.perst.IResource

exclusiveLock, exclusiveLock, reset, sharedLock, sharedLock, unlock

Methods inherited from interface org.garret.perst.ITable

select

Method Detail

clear

public void clear()

Remove all objects from the index

get

public int get(IPersistent obj)

Get properties of specified object

Parameters:

obj - object which properties are requested

Returns:

bit mask associated with this objects

Throws:

StorageError(StorageError.KEY_NOT_FOUND) - exception if there is no object in the index

iterator

public java.util.Iterator iterator()

Get iterator through all objects in the index This iterator doesn't support remove() method. It is not possible to modify bit index during iteration.

Specified by:

iterator in interface ITable

Returns:

iterator through all objects in the index

iterator

public java.util.Iterator iterator(int set,
                                   int clear)

Get iterator for selecting objects with specified properties. To select all record this method should be invoked with (0, 0) parameters This iterator doesn't support remove() method. It is not possible to modify bit index during iteration.

Parameters:

set - bitmask specifying bits which should be set (1)

clear - bitmask specifying bits which should be cleared (0)

Returns:

selection iterator

put

public void put(IPersistent obj,
                int mask)

Put new object in the index. If such objct already exists in index, then its mask will be rewritten

Parameters:

obj - object to be placed in the index. Object can be not yet peristent, in this case its forced to become persistent by assigning OID to it.

mask - bit mask associated with this objects

remove

public void remove(IPersistent obj)

Remove object from the index

Parameters:

obj - object removed from the index

Throws:

StorageError(StorageError.KEY_NOT_FOUND) - exception if there is no such object in the index

size

public int size()

Get number of objects in the index

Specified by:

size in interface ITable

Returns:

number of objects in the index