com.arjuna.ats.internal.arjuna.objectstore

Class LogStore

java.lang.Object

com.arjuna.ats.arjuna.objectstore.ObjectStore

com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore

com.arjuna.ats.internal.arjuna.objectstore.LogStore

All Implemented Interfaces:

BaseStore, ObjectStoreAPI, ParticipantStore, RecoveryStore, TxLog

public class LogStore
extends FileSystemStore

Field Summary

Fields

Modifier and Type	Field and Description
static long	LOG_SIZE

Fields inherited from class com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore

doSync, scanZeroLengthFiles, syncWrites

Fields inherited from class com.arjuna.ats.arjuna.objectstore.ObjectStore

_objectStoreRoot, shareStatus

Constructor Summary

Constructors

Constructor and Description
LogStore(ObjectStoreEnvironmentBean objectStoreEnvironmentBean)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	allLogUids(String tName, InputObjectState state, int match)
boolean	allObjUids(String tName, InputObjectState state, int match) This is a recovery-only method and should not be called during normal execution.
boolean	commit_state(Uid objUid, String tName) Commit a previous write_state operation which was made with the SHADOW StateType argument.
int	currentState(Uid objUid, String tName) Normally returns the current state of the log entry.
protected String	genPathName(Uid objUid, String tName, int ft)
boolean	hide_state(Uid u, String tn) Hide the object's state in the object store.
protected boolean	lock(File fd, int lmode, boolean create) Lock the file in the object store.
protected InputObjectState	read_state(Uid u, String tn, int s) Shouldn't be called during normal execution only during recovery.
InputObjectState	read_uncommitted(Uid u, String tn) Read the object's shadowed state.
protected boolean	remove_state(Uid u, String tn, int s) Does nothing except indicate that this thread is finished with the log on behalf of this transaction.
boolean	remove_uncommitted(Uid u, String tn) Remove the object's uncommitted state.
boolean	reveal_state(Uid u, String tn) Reveal a hidden object's state.
protected boolean	unlock(File fd) Unlock the file in the object store.
protected boolean	unlockAndClose(File fd, RandomAccessFile rf) Unlock and close the file.
boolean	write_committed(Uid storeUid, String tName, OutputObjectState state) Write a new copy of the object's committed state.
protected boolean	write_state(Uid objUid, String tName, OutputObjectState state, int ft) write_state saves the ObjectState in a file named by the type and Uid of the ObjectState.
boolean	write_uncommitted(Uid u, String tn, OutputObjectState s) Write a copy of the object's uncommitted state.

Methods inherited from class com.arjuna.ats.internal.arjuna.objectstore.FileSystemStore

addToCache, allTypes, allTypes, closeAndUnlock, createHierarchy, exists, getStoreName, openAndLock, read_committed, remove_committed, removeFromCache, removeFromCache, renameFromTo, supressEntry, synchronousWrites, truncate

Methods inherited from class com.arjuna.ats.arjuna.objectstore.ObjectStore

allObjUids, fullCommitNeeded, initialise, isType, locateStore, revealedId, shareState, start, stop, storeDir, storeRoot, sync

Methods inherited from class java.lang.Object

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

Field Detail

LOG_SIZE

public static final long LOG_SIZE

See Also:

Constant Field Values

Constructor Detail

LogStore

public LogStore(ObjectStoreEnvironmentBean objectStoreEnvironmentBean)
         throws ObjectStoreException

Throws:

ObjectStoreException

Method Detail

currentState

public int currentState(Uid objUid,
               String tName)
                 throws ObjectStoreException

Normally returns the current state of the log entry. However, this is never called during normal (non-recovery) execution. Therefore, the overhead of having to scan all of the logs (if it's not one we're using) is minimal.

Parameters:

objUid - The object to query.

tName - The type of the object to query.

Returns:

the current state of the object's state (e.g., shadowed, committed ...) [StateStatus]

Throws:

ObjectStoreException

commit_state

public boolean commit_state(Uid objUid,
                   String tName)
                     throws ObjectStoreException

Commit a previous write_state operation which was made with the SHADOW StateType argument. This is achieved by renaming the shadow and removing the hidden version.

Parameters:

objUid - The object to work on.

tName - The type of the object to work on.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

hide_state

public boolean hide_state(Uid u,
                 String tn)
                   throws ObjectStoreException

Description copied from interface: RecoveryStore

Hide the object's state in the object store. Used by crash recovery.

Parameters:

u - The object to work on.

tn - The type of the object to work on.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

reveal_state

public boolean reveal_state(Uid u,
                   String tn)
                     throws ObjectStoreException

Description copied from interface: RecoveryStore

Reveal a hidden object's state.

Parameters:

u - The object to work on.

tn - The type of the object to work on.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

read_uncommitted

public InputObjectState read_uncommitted(Uid u,
                                String tn)
                                  throws ObjectStoreException

Description copied from interface: ParticipantStore

Read the object's shadowed state.

Specified by:

read_uncommitted in interface ParticipantStore

Overrides:

read_uncommitted in class FileSystemStore

Parameters:

u - The object to work on.

tn - The type of the object to work on.

Returns:

the state of the object.

Throws:

ObjectStoreException

remove_uncommitted

public boolean remove_uncommitted(Uid u,
                         String tn)
                           throws ObjectStoreException

Description copied from interface: ParticipantStore

Remove the object's uncommitted state.

Specified by:

remove_uncommitted in interface ParticipantStore

Overrides:

remove_uncommitted in class FileSystemStore

Parameters:

u - The object to work on.

tn - The type of the object to work on.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

write_committed

public boolean write_committed(Uid storeUid,
                      String tName,
                      OutputObjectState state)
                        throws ObjectStoreException

Description copied from interface: TxLog

Write a new copy of the object's committed state.

Specified by:

write_committed in interface TxLog

Overrides:

write_committed in class FileSystemStore

Parameters:

storeUid - The object to work on.

tName - The type of the object to work on.

state - The state to write.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

write_uncommitted

public boolean write_uncommitted(Uid u,
                        String tn,
                        OutputObjectState s)
                          throws ObjectStoreException

Description copied from interface: ParticipantStore

Write a copy of the object's uncommitted state.

Specified by:

write_uncommitted in interface ParticipantStore

Overrides:

write_uncommitted in class FileSystemStore

Parameters:

u - The object to work on.

tn - The type of the object to work on.

s - The state to write.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

allLogUids

public boolean allLogUids(String tName,
                 InputObjectState state,
                 int match)
                   throws ObjectStoreException

Throws:

ObjectStoreException

allObjUids

public boolean allObjUids(String tName,
                 InputObjectState state,
                 int match)
                   throws ObjectStoreException

This is a recovery-only method and should not be called during normal execution. As such we need to load in all of the logs we can find that aren't already loaded (or activated).

Specified by:

allObjUids in interface RecoveryStore

Overrides:

allObjUids in class FileSystemStore

Parameters:

tName - The type to scan for.

state - The object state in which to store the Uids

match - The file type to look for (e.g., committed, shadowed). [StateStatus]

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

unlockAndClose

protected boolean unlockAndClose(File fd,
                     RandomAccessFile rf)

Unlock and close the file. Note that if the unlock fails we set the return value to false to indicate an error but rely on the close to really do the unlock.

write_state

protected boolean write_state(Uid objUid,
                  String tName,
                  OutputObjectState state,
                  int ft)
                       throws ObjectStoreException

write_state saves the ObjectState in a file named by the type and Uid of the ObjectState. If the second argument is SHADOW, then the file name is different so that a subsequent commit_state invocation will rename the file. We need to make sure that each entry is written to the next empty location in the log even if there's already an entry for this tx.

Specified by:

write_state in class FileSystemStore

Throws:

ObjectStoreException

read_state

protected InputObjectState read_state(Uid u,
                          String tn,
                          int s)
                               throws ObjectStoreException

Shouldn't be called during normal execution only during recovery.

Specified by:

read_state in class FileSystemStore

Throws:

ObjectStoreException

remove_state

protected boolean remove_state(Uid u,
                   String tn,
                   int s)
                        throws ObjectStoreException

Does nothing except indicate that this thread is finished with the log on behalf of this transaction.

Specified by:

remove_state in class FileSystemStore

Throws:

ObjectStoreException

lock

protected boolean lock(File fd,
           int lmode,
           boolean create)

Description copied from class: FileSystemStore

Lock the file in the object store.

Overrides:

lock in class FileSystemStore

unlock

protected boolean unlock(File fd)

Description copied from class: FileSystemStore

Unlock the file in the object store.

Overrides:

unlock in class FileSystemStore

genPathName

protected String genPathName(Uid objUid,
                 String tName,
                 int ft)
                      throws ObjectStoreException

Overrides:

genPathName in class FileSystemStore

Returns:

the file name for the state of the object identified by the Uid and TypeName. If the StateType argument is OS_SHADOW then the Uid part of the name includes # characters. The magic number SLOP below is the number of extra characters needed to make up the entire path.

Throws:

ObjectStoreException