gr.uoa.di.madgik.commons.state.store.registry

Class StateStoreRegistryKey

java.lang.Object

gr.uoa.di.madgik.commons.state.store.registry.StateStoreRegistryKey

public class StateStoreRegistryKey
extends Object

The StateStoreRegistryKey class holds metadata information for one entry registrered with the State repository. The metadata kept for each such entry include the key with which the entry is identified, the offset within the registry file that this metadata entry is persisted, the location of the actual data the key is associated with in the data file, whether or not the entry is to be considered active or a client has deleted it and the type of the entry data.

Author:

gpapanikos

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	StateStoreRegistryKey.EntryType The type of data an entry persisted with the state repository holds

Constructor Summary

Constructors

Constructor and Description
StateStoreRegistryKey() Creates a new instance
StateStoreRegistryKey(String Key, long StartingDataOffset, long EndingDataOffset, long StartingRegistryOffset, StateStoreRegistryKey.EntryType TypeOfEntry) Creates a new instance with the provided values

Method Summary

Methods

Modifier and Type	Method and Description
void	Deactivate() Sets the entry as deactivated
void	Decode(DataInputStream stream) Decodes a StateStoreRegistryKey as the Encode(java.io.RandomAccessFile) wrote it in the provided file.
void	Encode(RandomAccessFile stream) Stores this instance in the provided file leaving the file pointer at the end of the written entry.
long	GetEndingDataOffset() Retrieves the ending offset in the data fale where the entry's data are stored
String	GetKey() Retrieves the key with which the entry is identified
long	GetStartingDataOffset() Retrieves the offset in the data falie where the entry's data are stored
long	GetStartingRegistryOffset() Retrieves the offset in the registry file where this metadata entry is stored
StateStoreRegistryKey.EntryType	GetTypeOfEntry() Retrieves the type of entry
Boolean	IsActive() Whether or not the entry is considered active or it has been deleted
void	SetEndingDataOffset(long Offset) Sets the ending offset in the data fale where the entry's data are stored
void	SetStartingDataOffset(long Offset) Sets the offset in the data falie where the entry's data are stored
void	SetStartingRegistryOffset(long Offset) Sets the offset in the registry file where this metadata entry is stored

Methods inherited from class java.lang.Object

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

Constructor Detail

StateStoreRegistryKey

public StateStoreRegistryKey()

Creates a new instance

StateStoreRegistryKey

public StateStoreRegistryKey(String Key,
                     long StartingDataOffset,
                     long EndingDataOffset,
                     long StartingRegistryOffset,
                     StateStoreRegistryKey.EntryType TypeOfEntry)

Creates a new instance with the provided values

Parameters:

Key - The key with which this entry is reachable

StartingDataOffset - The starting offset of the actual data in the data file

EndingDataOffset - The ending offset of the actual data in the data file

StartingRegistryOffset - The starting offset of this metadata record in the registry file

TypeOfEntry - The type of the actual data stored

Method Detail

IsActive

public Boolean IsActive()

Whether or not the entry is considered active or it has been deleted

Returns:

whether or not the entry is considered active or it has been deactivated

Deactivate

public void Deactivate()

Sets the entry as deactivated

GetKey

public String GetKey()

Retrieves the key with which the entry is identified

Returns:

The key

GetTypeOfEntry

public StateStoreRegistryKey.EntryType GetTypeOfEntry()

Retrieves the type of entry

Returns:

the type of entry

GetStartingRegistryOffset

public long GetStartingRegistryOffset()

Retrieves the offset in the registry file where this metadata entry is stored

Returns:

the offset

SetStartingRegistryOffset

public void SetStartingRegistryOffset(long Offset)

Sets the offset in the registry file where this metadata entry is stored

Parameters:

Offset - the offset

GetStartingDataOffset

public long GetStartingDataOffset()

Retrieves the offset in the data falie where the entry's data are stored

Returns:

the offset

SetStartingDataOffset

public void SetStartingDataOffset(long Offset)

Sets the offset in the data falie where the entry's data are stored

Parameters:

Offset - the offset

GetEndingDataOffset

public long GetEndingDataOffset()

Retrieves the ending offset in the data fale where the entry's data are stored

Returns:

The offset

SetEndingDataOffset

public void SetEndingDataOffset(long Offset)

Sets the ending offset in the data fale where the entry's data are stored

Parameters:

Offset - the offset

Encode

public void Encode(RandomAccessFile stream)
            throws Exception

Stores this instance in the provided file leaving the file pointer at the end of the written entry. The method also update the position of the metadata entry it just written to point to the position of the file it started serializing its content

Parameters:

stream - the file to write the entry to

Throws:

Exception - The encoding could not be performed

Decode

public void Decode(DataInputStream stream)
            throws Exception

Decodes a StateStoreRegistryKey as the Encode(java.io.RandomAccessFile) wrote it in the provided file.

Parameters:

stream - The file to read the entry from

Throws:

Exception - The decoding could not be performed