FreeListBlock (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- net.metanotion.io.block.FreeListBlock

```
class FreeListBlock
extends Object
```
Manages free pages in a block file.
Tracks available pages for allocation using a linked list of blocks. Each block contains multiple free page references and fits on a single disk page.
On-disk format:
```
    Magic number (long)
    next freelist block page (unsigned int)
    size (unsigned int)
    that many free pages (unsigned ints)
 
```
Free page format:
```
    Magic number (long)
 
```

Field Summary
Fields
Modifier and Type Field and Description
int page
Page number of this free list block.

Fields
Modifier and Type	Field and Description
`int`	`page` Page number of this free list block.

Constructor Summary
Constructors
Constructor and Description
FreeListBlock(RandomAccessInterface file, int startPage)
Constructor.

Constructors
Constructor and Description
`FreeListBlock(RandomAccessInterface file, int startPage)` Constructor.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`addPage(int freePage)` Adds free page and writes new len to disk
`boolean`	`flbck(boolean fix)`
`int`	`getNextPage()`
`static void`	`initPage(RandomAccessInterface file, int page)` Initialize a new free list block page with default values.
`boolean`	`isEmpty()`
`boolean`	`isFull()`
`void`	`setNextPage(int nxt)` Set and write the next page only
`int`	`takePage()` Takes next page and writes new len to disk
`String`	`toString()`
`void`	`writeBlock()` Write this block's data to disk.

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

- Field Detail
  - page
```
public final int page
```
    Page number of this free list block.
- Constructor Detail
  - FreeListBlock
```
public FreeListBlock(RandomAccessInterface file,
                     int startPage)
              throws IOException
```
    Constructor.
    Parameters:
    file - the block file
    startPage - starting page number
    Throws:
    IOException - on I/O error
- Method Detail
  - addPage
```
public void addPage(int freePage)
             throws IOException
```
    Adds free page and writes new len to disk
    Throws:
    IllegalStateException - if full
    IOException
  - flbck
```
public boolean flbck(boolean fix)
              throws IOException
```
    Throws:
    IOException
  - getNextPage
```
public int getNextPage()
```
    Returns:
    the next page
  - initPage
```
public static void initPage(RandomAccessInterface file,
                            int page)
                     throws IOException
```
    Initialize a new free list block page with default values.
    Throws:
    IOException
  - isEmpty
```
public boolean isEmpty()
```
    Returns:
    whether empty
  - isFull
```
public boolean isFull()
```
    Returns:
    whether full
  - setNextPage
```
public void setNextPage(int nxt)
                 throws IOException
```
    Set and write the next page only
    Throws:
    IOException
  - takePage
```
public int takePage()
             throws IOException
```
    Takes next page and writes new len to disk
    Throws:
    IllegalStateException - if empty
    IOException
  - toString
```
public String toString()
```
    Overrides:
    toString in class Object
    Returns:
    a string representation of this block
  - writeBlock
```
public void writeBlock()
                throws IOException
```
    Write this block's data to disk.
    Throws:
    IOException

Class FreeListBlock

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

page

Constructor Detail

FreeListBlock

Method Detail

addPage

flbck

getNextPage

initPage

isEmpty

isFull

setNextPage

takePage

toString

writeBlock