com.arjuna.ats.internal.arjuna.objectstore

Class FileSystemStore

java.lang.Object

com.arjuna.ats.arjuna.objectstore.ObjectStore

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

All Implemented Interfaces:

BaseStore, ObjectStoreAPI, ParticipantStore, RecoveryStore, TxLog

Direct Known Subclasses:

FileLockingStore, LogStore, ShadowingStore

public abstract class FileSystemStore
extends ObjectStore

The basic class for file system object stores. This is not actually an object store implementation, since other classes must provide implementations of the abstract methods. It does provide implementations of common methods though.

Since:

JTS 1.0.

Version:

$Id: FileSystemStore.java 2342 2006-03-30 13:06:17Z $

Author:

Mark Little (mark@arjuna.com)

Field Summary

Fields

Modifier and Type	Field and Description
protected boolean	doSync
protected boolean	scanZeroLengthFiles
protected boolean	syncWrites

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

_objectStoreRoot, shareStatus

Constructor Summary

Constructors

Constructor and Description
FileSystemStore(ObjectStoreEnvironmentBean objectStoreEnvironmentBean)

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addToCache(String fname)
boolean	allObjUids(String tName, InputObjectState state, int match) Given a type name initialise the state to contains all of the Uids of objects of that type
boolean	allTypes(InputObjectState foundTypes) Obtain all types of objects stored in the object store.
protected boolean	allTypes(OutputObjectState foundTypes, String root)
protected boolean	closeAndUnlock(File fd, FileInputStream ifile, FileOutputStream ofile) Unlock and close the file.
protected boolean	createHierarchy(String path) Attempt to build up the object store in the file system dynamically.
protected boolean	exists(String path) If this object store implementation is exclusively working on a set of object states, then this method will check a file cache first.
protected String	genPathName(Uid objUid, String tName, int ostype)
String	getStoreName()
protected boolean	lock(File fd, int lmode, boolean create) Lock the file in the object store.
protected File	openAndLock(String fname, int lmode, boolean create)
InputObjectState	read_committed(Uid storeUid, String tName) Read the object's committed state.
protected abstract InputObjectState	read_state(Uid u, String tn, int s)
InputObjectState	read_uncommitted(Uid storeUid, String tName) Read the object's shadowed state.
boolean	remove_committed(Uid storeUid, String tName) Remove the object's committed state.
protected abstract boolean	remove_state(Uid u, String tn, int s)
boolean	remove_uncommitted(Uid storeUid, String tName) Remove the object's uncommitted state.
protected void	removeFromCache(String fname)
protected void	removeFromCache(String fname, boolean warn) Print a warning if the file to be removed is not in the cache.
protected boolean	renameFromTo(File from, File to)
protected boolean	supressEntry(String name) Suppress directories of the specified type from allTypes etc?
protected boolean	synchronousWrites() Are synchronous write enabled?
protected String	truncate(String value)
protected boolean	unlock(File fd) Unlock the file in the object store.
boolean	write_committed(Uid storeUid, String tName, OutputObjectState state) Write a new copy of the object's committed state.
protected abstract boolean	write_state(Uid u, String tn, OutputObjectState buff, int s)
boolean	write_uncommitted(Uid storeUid, String tName, OutputObjectState state) Write a copy of the object's uncommitted state.

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

Methods inherited from interface com.arjuna.ats.arjuna.objectstore.ParticipantStore

commit_state

Methods inherited from interface com.arjuna.ats.arjuna.objectstore.RecoveryStore

currentState, hide_state, reveal_state

Field Detail

syncWrites

protected boolean syncWrites

doSync

protected volatile boolean doSync

scanZeroLengthFiles

protected boolean scanZeroLengthFiles

Constructor Detail

FileSystemStore

public FileSystemStore(ObjectStoreEnvironmentBean objectStoreEnvironmentBean)
                throws ObjectStoreException

Throws:

ObjectStoreException

Method Detail

getStoreName

public String getStoreName()

Returns:

the "name" of the object store. Where in the hierarchy it appears, e.g., /ObjectStore/MyName/...

read_committed

public InputObjectState read_committed(Uid storeUid,
                              String tName)
                                throws ObjectStoreException

Description copied from interface: ParticipantStore

Read the object's committed state.

Parameters:

storeUid - The object to work on.

tName - The type of the object to work on.

Returns:

the state of the object.

Throws:

ObjectStoreException

read_uncommitted

public InputObjectState read_uncommitted(Uid storeUid,
                                String tName)
                                  throws ObjectStoreException

Description copied from interface: ParticipantStore

Read the object's shadowed state.

Parameters:

storeUid - The object to work on.

tName - The type of the object to work on.

Returns:

the state of the object.

Throws:

ObjectStoreException

remove_committed

public boolean remove_committed(Uid storeUid,
                       String tName)
                         throws ObjectStoreException

Description copied from interface: TxLog

Remove the object's committed state.

Parameters:

storeUid - The object to work on.

tName - The type of the object to work on.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

remove_uncommitted

public boolean remove_uncommitted(Uid storeUid,
                         String tName)
                           throws ObjectStoreException

Description copied from interface: ParticipantStore

Remove the object's uncommitted state.

Parameters:

storeUid - The object to work on.

tName - 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.

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 storeUid,
                        String tName,
                        OutputObjectState state)
                          throws ObjectStoreException

Description copied from interface: ParticipantStore

Write a copy of the object's uncommitted state.

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

allObjUids

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

Given a type name initialise the state to contains all of the Uids of objects of that type

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

allTypes

public boolean allTypes(InputObjectState foundTypes)
                 throws ObjectStoreException

Description copied from interface: RecoveryStore

Obtain all types of objects stored in the object store.

Parameters:

foundTypes - The state in which to store the types.

Returns:

true if no errors occurred, false otherwise.

Throws:

ObjectStoreException

read_state

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

Throws:

ObjectStoreException

remove_state

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

Throws:

ObjectStoreException

write_state

protected abstract boolean write_state(Uid u,
                  String tn,
                  OutputObjectState buff,
                  int s)
                                throws ObjectStoreException

Throws:

ObjectStoreException

synchronousWrites

protected final boolean synchronousWrites()

Are synchronous write enabled?

lock

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

Lock the file in the object store.

unlock

protected boolean unlock(File fd)

Unlock the file in the object store.

closeAndUnlock

protected boolean closeAndUnlock(File fd,
                     FileInputStream ifile,
                     FileOutputStream ofile)

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.

openAndLock

protected File openAndLock(String fname,
               int lmode,
               boolean create)
                    throws ObjectStoreException

Throws:

ObjectStoreException

renameFromTo

protected final boolean renameFromTo(File from,
                   File to)

allTypes

protected boolean allTypes(OutputObjectState foundTypes,
               String root)
                    throws ObjectStoreException

Throws:

ObjectStoreException

genPathName

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

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

supressEntry

protected boolean supressEntry(String name)

Description copied from class: ObjectStore

Suppress directories of the specified type from allTypes etc?

Specified by:

supressEntry in class ObjectStore

truncate

protected String truncate(String value)

createHierarchy

protected final boolean createHierarchy(String path)
                                 throws ObjectStoreException

Attempt to build up the object store in the file system dynamically. This creates directories as required as new types are added to the store. Note that we made sure the root object store was created and writable at construction time. WARNING: on a multi-processor box it is possible that multiple threads may try to create the same hierarchy at the same time. What will tend to happen is that one thread will succeed and the other(s) will fail. However, if a failed thread just assumes that the directory is being created by another thread, then we're in trouble, because although this may be the case, the directory structure may not have actually been created - it may still be in the process of being created. So, we have to err on the side of caution and try to create the directory a few times. (This can happen across processes too.)

Throws:

ObjectStoreException

exists

protected final boolean exists(String path)

If this object store implementation is exclusively working on a set of object states, then this method will check a file cache first. Otherwise, we must go back to the file system each time to check the status of the file. If we add a FileDescriptor cache a la the C++ version then we would be able to get rid of the state cache and simply check to see if we had a fd for it.

addToCache

protected final void addToCache(String fname)

removeFromCache

protected final void removeFromCache(String fname)

removeFromCache

protected final void removeFromCache(String fname,
                   boolean warn)

Print a warning if the file to be removed is not in the cache.

Since:

2.1.1.