FileSequence (Commons Transaction 1.3-SNAPSHOT API)

java.lang.Object
- org.apache.commons.transaction.file.FileSequence

```
public class FileSequence
extends Object
```
Fail-Safe sequence store implementation using the file system. Works by versioning values of sequences and throwing away all versions, but the current and the previous one.

Version:

$Id: FileSequence.java 493628 2007-01-07 01:42:48Z joerg $

Field Summary

Fields
Modifier and Type Field and Description

protected LoggerFacade logger

protected String storeDir

Fields
Modifier and Type	Field and Description
`protected LoggerFacade`	`logger`
`protected String`	`storeDir`

Constructor Summary

Constructors
Constructor and Description

FileSequence(String storeDir, LoggerFacade logger)
Creates a new resouce manager operation on the specified directories.

Constructors
Constructor and Description
`FileSequence(String storeDir, LoggerFacade logger)` Creates a new resouce manager operation on the specified directories.

Method Summary

Methods
Modifier and Type	Method and Description
`boolean`	`create(String sequenceName, long initialValue)` Creates a sequence if it does not already exist.
`boolean`	`delete(String sequenceName)` Deletes a sequence if it exists.
`boolean`	`exists(String sequenceName)` Checks if the sequence already exists.
`protected String`	`getPathI(String sequenceName)`
`protected String`	`getPathII(String sequenceName)`
`long`	`nextSequenceValueBottom(String sequenceName, long increment)` Gets the next value of the sequence.
`protected long`	`read(String sequenceName)`
`protected long`	`readFromPath(String path)`
`protected void`	`write(String sequenceName, long value)`
`protected void`	`writeToPath(String path, long value)`

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - storeDir
```
protected final String storeDir
```
  - logger
```
protected final LoggerFacade logger
```
- Constructor Detail
  - FileSequence
```
public FileSequence(String storeDir,
            LoggerFacade logger)
             throws ResourceManagerException
```
    Creates a new resouce manager operation on the specified directories.
    
    Parameters:
    storeDir - directory where sequence information is stored
    logger - logger used for warnings only
    
    Throws:
    
    ResourceManagerException
- Method Detail
  - exists
```
public boolean exists(String sequenceName)
```
    Checks if the sequence already exists.
    
    Parameters:
    sequenceName - the name of the sequence you want to check
    
    Returns:
    true if the sequence already exists, false otherwise
  - create
```
public boolean create(String sequenceName,
             long initialValue)
               throws ResourceManagerException
```
    Creates a sequence if it does not already exist.
    
    Parameters:
    sequenceName - the name of the sequence you want to create
    
    Returns:
    true if the sequence has been created, false if it already existed
    
    Throws:
    
    ResourceManagerException - if anything goes wrong while accessing the sequence
  - delete
```
public boolean delete(String sequenceName)
```
    Deletes a sequence if it exists.
    
    Parameters:
    sequenceName - the name of the sequence you want to delete
    
    Returns:
    true if the sequence has been deleted, false if not
  - nextSequenceValueBottom
```
public long nextSequenceValueBottom(String sequenceName,
                           long increment)
                             throws ResourceManagerException
```
    Gets the next value of the sequence.
    
    Parameters:
    sequenceName - the name of the sequence you want the next value for
    increment - the increment for the sequence, i.e. how much to add to the sequence with this call
    
    Returns:
    the next value of the sequence not yet incremented, i.e. the increment is recorded internally, but not returned with the next call to this method
    
    Throws:
    
    ResourceManagerException - if anything goes wrong while accessing the sequence
  - read
```
protected long read(String sequenceName)
             throws ResourceManagerException
```
    Throws:
    
    ResourceManagerException
  - write
```
protected void write(String sequenceName,
         long value)
              throws ResourceManagerException
```
    Throws:
    
    ResourceManagerException
  - getPathI
```
protected String getPathI(String sequenceName)
```
  - getPathII
```
protected String getPathII(String sequenceName)
```
  - readFromPath
```
protected long readFromPath(String path)
                     throws ResourceManagerException,
                            NumberFormatException,
                            FileNotFoundException,
                            IOException
```
    Throws:
    
    ResourceManagerException
    
    NumberFormatException
    
    FileNotFoundException
    
    IOException
  - writeToPath
```
protected void writeToPath(String path,
               long value)
                    throws ResourceManagerException
```
    Throws:
    
    ResourceManagerException

Class FileSequence

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

storeDir

logger

Constructor Detail

FileSequence

Method Detail

exists

create

delete

nextSequenceValueBottom

read

write

getPathI

getPathII

readFromPath

writeToPath