org.apache.derby.iapi.store.access
Interface FileResource

All Known Implementing Classes:

RFResource

public interface FileResource

Management of file resources within a database. Suitable for jar files, images etc.

A file resource is identified by the pair (name,generationId). Name is an arbitrary String supplied by the caller. GenerationId is a non-repeating sequence number constructed by the database. Within a database a (name,generationId) pair uniquely identifies a version of a file resource for all time. Newer generation numbers reflect newer versions of the file.

A database supports the concept of a designated current version of a fileResource. The management of the current version is transactional. The following rules apply

1. Adding a FileResource makes the added version the current version
2. Removing a FileResource removes the current version of the resource. After this operation the database holds no current version of the FileResoure.
3. Replacing a FileResource removes the current version of the resource.

For the benefit of replication, a database optionally retains historic versions of stored files. These old versions are useful when processing old transactions in the stage.

Field Summary

static java.lang.String

JAR_DIRECTORY_NAME The name of the jar directory

Method Summary

long	add(java.lang.String name, java.io.InputStream source) Add a file resource, copying from the input stream.
StorageFile	getAsFile(java.lang.String name, long generationId) Get the StorageFile for a file resource.
char	getSeparatorChar()
void	remove(java.lang.String name, long currentGenerationId) Remove the current generation of a file resource from the database.
void	removeJarDir(java.lang.String f) During hard upgrade to >= 10.9, remove a jar directory (at post-commit time) from the database.
long	replace(java.lang.String name, long currentGenerationId, java.io.InputStream source) Replace a file resource with a new version.

Field Detail

JAR_DIRECTORY_NAME

static final java.lang.String JAR_DIRECTORY_NAME

The name of the jar directory

See Also:

Constant Field Values

Method Detail

add

long add(java.lang.String name,
         java.io.InputStream source)
         throws StandardException

Add a file resource, copying from the input stream. The InputStream will be closed by this method.

Parameters:

name - the name of the file resource.

source - an input stream for reading the content of the file resource.

Returns:

the generationId for the file resource. This quantity increases when you replace the file resource.

Throws:

StandardException - some error occured.

remove

void remove(java.lang.String name,
            long currentGenerationId)
            throws StandardException

Remove the current generation of a file resource from the database.

Parameters:

name - the name of the fileResource to remove.

Throws:

StandardException - some error occured.

removeJarDir

void removeJarDir(java.lang.String f)
                  throws StandardException

During hard upgrade to >= 10.9, remove a jar directory (at post-commit time) from the database.

Parameters:

f -

Throws:

standard - error policy

StandardException

replace

long replace(java.lang.String name,
             long currentGenerationId,
             java.io.InputStream source)
             throws StandardException

Replace a file resource with a new version.

The InputStream will be closed by this method.

Parameters:

name - the name of the file resource.

source - an input stream for reading the content of the file resource.

Returns:

the generationId for the new 'current' version of the file resource.

Throws:

StandardException - some error occured.

getAsFile

StorageFile getAsFile(java.lang.String name,
                      long generationId)

Get the StorageFile for a file resource.

Parameters:

name - The name of the fileResource

generationId - the generationId of the fileResource

Returns:

A StorageFile object representing the file.

getSeparatorChar

char getSeparatorChar()

Returns:

the separator character to be used in file names.