casa.io

Class CASAFileFreeList

java.lang.Object

casa.io.CASAFileFreeList

public class CASAFileFreeList
extends Object

A representation of the free blocks list within a CASAFile. This class is of limited utility outside of the casa.io.package.

Copyright: Copyright 2003-2014, Knowledge Science Group, University of Calgary. Permission to use, copy, modify, distribute and sell this software and its documentation for any purpose is hereby granted without fee, provided that the above copyright notice appear in all copies and that both that copyright notice and this permission notice appear in supporting documentation. The Knowledge Science Group makes no representations about the suitability of this software for any purpose. It is provided "as is" without express or implied warranty.

Version:

0.9

Author:

Rob Kremer

Field Summary

Fields

Modifier and Type	Field and Description
private CASAFile	file
static String	FREE_LIST_ENTRY_NAME The reserved index name for the free list

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	CASAFileFreeList(CASAFile aFile)

Method Summary

Modifier and Type	Method and Description
protected void	addBlock(long freeBlock) Add a block to the free list.
protected long	getBlock() Remove a block from the free list and returns the file offset to it.
Vector	getFreeBlocks() Get a list of the file offsets to any free blocks.
boolean	hasBlocks() simple method to determine if the free list is empty or not

Methods inherited from class java.lang.Object

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

Field Detail

FREE_LIST_ENTRY_NAME

public static final String FREE_LIST_ENTRY_NAME

The reserved index name for the free list

See Also:

Constant Field Values

file

private CASAFile file

Constructor Detail

CASAFileFreeList

protected CASAFileFreeList(CASAFile aFile)

Method Detail

hasBlocks

public boolean hasBlocks()
                  throws CASAIOException,
                         IOException

simple method to determine if the free list is empty or not

Throws:

CASAIOException

IOException

getBlock

protected long getBlock()
                 throws IOException,
                        CASAIOException

Remove a block from the free list and returns the file offset to it.

Returns:

The offset to the free block or 0 if no free blocks. (0 is an invalid block offset)

Throws:

IOException

CASAIOException

addBlock

protected void addBlock(long freeBlock)
                 throws CASAIOException,
                        IOException

Add a block to the free list. The blocks' headers are reset.

Throws:

CASAIOException

IOException

getFreeBlocks

public Vector getFreeBlocks()
                     throws IOException,
                            CASAIOException

Get a list of the file offsets to any free blocks.

Returns:

null if file does not have a free block list, otherwise a Vector of Long offsets

Throws:

IOException

CASAIOException