BlockStore (POI API Documentation)

Overview

Package

Class

Tree

Deprecated

Index

Help

PREV CLASS NEXT CLASS

FRAMES NO FRAMES

SUMMARY: NESTED | FIELD | CONSTR | METHOD

DETAIL: FIELD | CONSTR | METHOD

org.apache.poi.poifs.filesystem
Class BlockStore

java.lang.Object
  org.apache.poi.poifs.filesystem.BlockStore

Direct Known Subclasses:: NPOIFSFileSystem, NPOIFSMiniStore

public abstract class BlockStore
extends java.lang.Object
extends java.lang.Object

This abstract class describes a way to read, store, chain and free a series of blocks (be they Big or Small ones)

Nested Class Summary
`protected class`	`BlockStore.ChainLoopDetector` Used to detect if a chain has a loop in it, so we can bail out with an error rather than spinning away for ever...

Constructor Summary
`BlockStore()`

Method Summary
`protected abstract java.nio.ByteBuffer`	`createBlockIfNeeded(int offset)` Extends the file if required to hold blocks up to the specified offset, and return the block from there.
`protected abstract BATBlock.BATBlockAndIndex`	`getBATBlockAndIndex(int offset)` Returns the BATBlock that handles the specified offset, and the relative index within it
`protected abstract java.nio.ByteBuffer`	`getBlockAt(int offset)` Load the block at the given offset.
`protected abstract int`	`getBlockStoreBlockSize()` Returns the size of the blocks managed through the block store.
`protected abstract BlockStore.ChainLoopDetector`	`getChainLoopDetector()` Creates a Detector for loops in the chain
`protected abstract int`	`getFreeBlock()` Finds a free block, and returns its offset.
`protected abstract int`	`getNextBlock(int offset)` Works out what block follows the specified one.
`protected abstract void`	`setNextBlock(int offset, int nextBlock)` Changes the record of what block follows the specified one.

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

Constructor Detail

BlockStore

public BlockStore()

Method Detail

getBlockStoreBlockSize

protected abstract int getBlockStoreBlockSize()

Returns the size of the blocks managed through the block store.

getBlockAt

protected abstract java.nio.ByteBuffer getBlockAt(int offset)
                                           throws java.io.IOException

Load the block at the given offset.

Throws:: java.io.IOException

createBlockIfNeeded

protected abstract java.nio.ByteBuffer createBlockIfNeeded(int offset)
                                                    throws java.io.IOException

Extends the file if required to hold blocks up to the specified offset, and return the block from there.

Throws:: java.io.IOException

getBATBlockAndIndex

protected abstract BATBlock.BATBlockAndIndex getBATBlockAndIndex(int offset)

Returns the BATBlock that handles the specified offset, and the relative index within it

getNextBlock

protected abstract int getNextBlock(int offset)

Works out what block follows the specified one.

setNextBlock

protected abstract void setNextBlock(int offset,
                                     int nextBlock)

Changes the record of what block follows the specified one.

getFreeBlock

protected abstract int getFreeBlock()
                             throws java.io.IOException

Finds a free block, and returns its offset. This method will extend the file/stream if needed, and if doing so, allocate new FAT blocks to address the extra space.

Throws:: java.io.IOException

getChainLoopDetector

protected abstract BlockStore.ChainLoopDetector getChainLoopDetector()
                                                              throws java.io.IOException

Creates a Detector for loops in the chain

Throws:: java.io.IOException