galileo.fs

Interface PhysicalGraph

All Known Implementing Classes:

FileSystem, GeospatialFileSystem

public interface PhysicalGraph

Defines the interface for "physical graphs" --- on-disk storage hierarchies.

Author:

malensek

Method Summary

Modifier and Type	Method and Description
Block	loadBlock(java.lang.String blockPath) Retrieves a Block instance, given its path on disk.
Metadata	loadMetadata(java.lang.String blockPath) Retrieves a Metadata instance, given a Block path on disk.
java.lang.String	storeBlock(Block block) Stores a Block on disk.
void	storeMetadata(Metadata metadata, java.lang.String blockPath) Inserts Metadata into the file system.

Method Detail

loadBlock

Block loadBlock(java.lang.String blockPath)
         throws java.io.IOException,
                galileo.serialization.SerializationException

Retrieves a Block instance, given its path on disk.

Parameters:

blockPath - the physical (on-disk) location of the Block to load.

Returns:

Block stored at blockPath.

Throws:

java.io.IOException

galileo.serialization.SerializationException

loadMetadata

Metadata loadMetadata(java.lang.String blockPath)
               throws java.io.IOException,
                      galileo.serialization.SerializationException

Retrieves a Metadata instance, given a Block path on disk.

Parameters:

blockPath - the physical location of the Block to load metadata from.

Returns:

Metadata stored in the Block specified by blockPath.

Throws:

java.io.IOException

galileo.serialization.SerializationException

storeBlock

java.lang.String storeBlock(Block block)
                     throws FileSystemException,
                            java.io.IOException

Stores a Block on disk. The location of the Block will be determined by the particular FileSystem implementation being used rather than as a method parameter, so only the Block itself is provided.

Parameters:

block - the Block instance to persist to disk.

Returns:

String representation of the Block path on disk.

Throws:

FileSystemException

java.io.IOException

storeMetadata

void storeMetadata(Metadata metadata,
                   java.lang.String blockPath)
            throws FileSystemException,
                   java.io.IOException

Inserts Metadata into the file system. In many cases, Metadata is not stored individually on disk but placed in an index instead. This method is useful during a full recovery operation for re-linking indexed Metadata with its associated files on disk, or could be used in situations where information should only be indexed and not stored.

Parameters:

metadata - the Metadata to 'store,' which may just involve updating index structures.

blockPath - the on-disk path of the Block the Metadata being stored belongs to.

Throws:

FileSystemException

java.io.IOException