BlockAllocationTableWriter (POI API Documentation)

java.lang.Object
- org.apache.poi.poifs.storage.BlockAllocationTableWriter

All Implemented Interfaces:

BATManaged, BlockWritable
```
public final class BlockAllocationTableWriter
extends java.lang.Object
implements BlockWritable, BATManaged
```
This class manages and creates the Block Allocation Table, which is basically a set of linked lists of block indices.
Each block of the filesystem has an index. The first block, the header, is skipped; the first block after the header is index 0, the next is index 1, and so on.
A block's index is also its index into the Block Allocation Table. The entry that it finds in the Block Allocation Table is the index of the next block in the linked list of blocks making up a file, or it is set to -2: end of list.

Constructor Summary

Constructors
Constructor and Description

BlockAllocationTableWriter(POIFSBigBlockSize bigBlockSize)
create a BlockAllocationTableWriter

Constructors
Constructor and Description
`BlockAllocationTableWriter(POIFSBigBlockSize bigBlockSize)` create a BlockAllocationTableWriter

Method Summary

Methods
Modifier and Type	Method and Description
`int`	`allocateSpace(int blockCount)` Allocate space for a block of indices
`int`	`countBlocks()` Return the number of BigBlock's this instance uses
`int`	`createBlocks()` Create the BATBlocks we need
`int`	`getStartBlock()` get the starting block
`void`	`setStartBlock(int start_block)` Set the start block for this instance
`static void`	`writeBlock(BATBlock bat, java.nio.ByteBuffer block)` Write the BAT into its associated block
`void`	`writeBlocks(java.io.OutputStream stream)` Write the storage to an OutputStream

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

- Constructor Detail
  - BlockAllocationTableWriter
```
public BlockAllocationTableWriter(POIFSBigBlockSize bigBlockSize)
```
    create a BlockAllocationTableWriter
- Method Detail
  - createBlocks
```
public int createBlocks()
```
    Create the BATBlocks we need
    
    Returns:
    start block index of BAT blocks
  - allocateSpace
```
public int allocateSpace(int blockCount)
```
    Allocate space for a block of indices
    
    Parameters:
    blockCount - the number of blocks to allocate space for
    
    Returns:
    the starting index of the blocks
  - getStartBlock
```
public int getStartBlock()
```
    get the starting block
    
    Returns:
    the starting block index
  - writeBlocks
```
public void writeBlocks(java.io.OutputStream stream)
                 throws java.io.IOException
```
    Write the storage to an OutputStream
    
    Specified by:
    
    writeBlocks in interface BlockWritable
    
    Parameters:
    stream - the OutputStream to which the stored data should be written
    
    Throws:
    
    java.io.IOException - on problems writing to the specified stream
  - writeBlock
```
public static void writeBlock(BATBlock bat,
              java.nio.ByteBuffer block)
                       throws java.io.IOException
```
    Write the BAT into its associated block
    
    Throws:
    
    java.io.IOException
  - countBlocks
```
public int countBlocks()
```
    Return the number of BigBlock's this instance uses
    
    Specified by:
    
    countBlocks in interface BATManaged
    
    Returns:
    count of BigBlock instances
  - setStartBlock
```
public void setStartBlock(int start_block)
```
    Set the start block for this instance
    
    Specified by:
    
    setStartBlock in interface BATManaged
    
    Parameters:
    start_block - index into the array of BigBlock instances making up the the filesystem

Class BlockAllocationTableWriter

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

BlockAllocationTableWriter

Method Detail

createBlocks

allocateSpace

getStartBlock

writeBlocks

writeBlock

countBlocks

setStartBlock