BSkipSpan (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.metanotion.util.skiplist.SkipSpan<K,V>
- - net.metanotion.io.block.index.BSkipSpan<K,V>

Type Parameters:: K - type of keys maintained by this skip span; V - type of values stored in this skip span

All Implemented Interfaces:: Flushable

Direct Known Subclasses:: IBSkipSpan

public class BSkipSpan<K extends Comparable<? super K>,V>
extends SkipSpan<K,V>

SkipList span implementation with in-memory key-value storage.

Stores all keys and values in memory for fast access while maintaining disk persistence. Supports overflow to additional pages when capacity is exceeded.

On-disk format:

   First Page:
     Magic number (int)
     overflow page (unsigned int)
     previous page (unsigned int)
     next page (unsigned int)
     max keys (unsigned short)
     number of keys (unsigned short)
     for each key:
         key length (unsigned short)
         value length (unsigned short)
         key data
         value data

   Overflow pages:
     Magic number (int)
     next overflow page (unsigned int)

Field Summary

Fields
Modifier and Type	Field and Description
`protected BlockFile`	`bf` Reference to the BlockFile
`static int`	`CONT_HEADER_LEN` Continuation page header length in bytes
`protected static int`	`HEADER_LEN` Fixed header length in bytes
`protected boolean`	`isKilled` Whether this span has been killed/deleted
`protected Serializer<K>`	`keySer` Key serializer
`protected static int`	`MAGIC` Magic number for span pages ("Span")
`protected int`	`nextPage` Next page number
`protected int`	`overflowPage` Overflow page number
`protected int`	`page` Page number of this span
`protected int`	`prevPage` Previous page number
`protected int`	`spanSize` Number of keys this span can hold
`protected Serializer<V>`	`valSer` Value serializer

Fields inherited from class net.metanotion.util.skiplist.SkipSpan
keys, MAX_SIZE, next, nKeys, prev, vals

Constructor Summary

Constructors
Modifier	Constructor and Description
`protected`	`BSkipSpan(BlockFile bf, BSkipList<K,V> bsl)` Create a new BSkipSpan with the given BlockFile and BSkipList.
	`BSkipSpan(BlockFile bf, BSkipList<K,V> bsl, int spanPage, Serializer<K> key, Serializer<V> val)` Create a BSkipSpan and load its data from disk.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`flush()` Flush this span to disk.
`static void`	`init(BlockFile bf, int page, int spanSize)` Initialize a new span page on disk.
`void`	`killInstance()` Mark this span instance as killed and free its resources.
`protected void`	`loadData()` Load the span's keys and values into memory (second half of load()).
`protected void`	`loadData(boolean flushOnError)` Load the span's keys and values into memory.
`protected static <X extends Comparable<? super X>,Y> void`	`loadInit(BSkipSpan<X,Y> bss, BlockFile bf, BSkipList<X,Y> bsl, int spanPage, Serializer<X> key, Serializer<Y> val)` Load the span headers from disk (first half of load()).
`protected void`	`lostEntries(int firstBadEntry, int lastGoodPage)` Attempt to recover from corrupt data in this span.
`SkipSpan<K,V>`	`newInstance(SkipList<K,V> sl)` Create a new instance of this span type.
`String`	`toString()` Get a string representation of this span.

Methods inherited from class net.metanotion.util.skiplist.SkipSpan
firstKey, get, getEnd, getSpan, print, put, remove

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

- Field Detail
  - bf
```
protected final BlockFile bf
```
    Reference to the BlockFile
  - CONT_HEADER_LEN
```
public static final int CONT_HEADER_LEN
```
    Continuation page header length in bytes
    See Also:
    Constant Field Values
  - HEADER_LEN
```
protected static final int HEADER_LEN
```
    Fixed header length in bytes
    See Also:
    Constant Field Values
  - isKilled
```
protected boolean isKilled
```
    Whether this span has been killed/deleted
  - keySer
```
protected Serializer<K extends Comparable<? super K>> keySer
```
    Key serializer
  - MAGIC
```
protected static final int MAGIC
```
    Magic number for span pages ("Span")
    See Also:
    Constant Field Values
  - nextPage
```
protected int nextPage
```
    Next page number
  - overflowPage
```
protected int overflowPage
```
    Overflow page number
  - page
```
protected int page
```
    Page number of this span
  - prevPage
```
protected int prevPage
```
    Previous page number
  - spanSize
```
protected int spanSize
```
    Number of keys this span can hold
  - valSer
```
protected Serializer<V> valSer
```
    Value serializer
- Constructor Detail
  - BSkipSpan
```
protected BSkipSpan(BlockFile bf,
                    BSkipList<K,V> bsl)
```
    Create a new BSkipSpan with the given BlockFile and BSkipList.
    Parameters:
    bf - the BlockFile
    bsl - the BSkipList
  - BSkipSpan
```
public BSkipSpan(BlockFile bf,
                 BSkipList<K,V> bsl,
                 int spanPage,
                 Serializer<K> key,
                 Serializer<V> val)
          throws IOException
```
    Create a BSkipSpan and load its data from disk.
    Parameters:
    bf - the BlockFile
    bsl - the BSkipList
    spanPage - the page number of this span
    key - the key
    val - the value serializer
    Throws:
    IOException - if an I/O error occurs
- Method Detail
  - flush
```
public void flush()
```
    Flush this span to disk.
    Specified by:
    flush in interface Flushable
    Overrides:
    flush in class SkipSpan<K extends Comparable<? super K>,V>
  - init
```
public static void init(BlockFile bf,
                        int page,
                        int spanSize)
                 throws IOException
```
    Initialize a new span page on disk.
    Parameters:
    bf - the BlockFile to write to
    page - the page number to initialize
    spanSize - the size of the span
    Throws:
    IOException - if an I/O error occurs
  - killInstance
```
public void killInstance()
```
    Mark this span instance as killed and free its resources.
    Overrides:
    killInstance in class SkipSpan<K extends Comparable<? super K>,V>
  - loadData
```
protected void loadData()
                 throws IOException
```
    Load the span's keys and values into memory (second half of load()).
    Throws:
    IOException - if an I/O error occurs
  - loadData
```
protected void loadData(boolean flushOnError)
                 throws IOException
```
    Load the span's keys and values into memory.
    Parameters:
    flushOnError - set to false if you are going to flush anyway
    Throws:
    IOException - if an I/O error occurs
  - loadInit
```
protected static <X extends Comparable<? super X>,Y> void loadInit(BSkipSpan<X,Y> bss,
                                                                   BlockFile bf,
                                                                   BSkipList<X,Y> bsl,
                                                                   int spanPage,
                                                                   Serializer<X> key,
                                                                   Serializer<Y> val)
                                                            throws IOException
```
    Load the span headers from disk (first half of load()). Only reads the span headers.
    Type Parameters:
    X - the key type
    Y - the value type
    Parameters:
    bss - the BSkipSpan to load into
    bf - the BlockFile
    bsl - the BSkipList
    spanPage - the page number
    key - the key
    val - the value serializer
    Throws:
    IOException - if an I/O error occurs
  - lostEntries
```
protected void lostEntries(int firstBadEntry,
                           int lastGoodPage)
```
    Attempt to recover from corrupt data in this span. All entries starting with firstBadEntry are lost. Zero out the overflow page on lastGoodPage, and correct the number of entries in the first page. We don't attempt to free the lost continuation pages.
    Parameters:
    firstBadEntry - the first entry index that is corrupted
    lastGoodPage - the last good page number
  - newInstance
```
public SkipSpan<K,V> newInstance(SkipList<K,V> sl)
```
    Create a new instance of this span type.
    Overrides:
    newInstance in class SkipSpan<K extends Comparable<? super K>,V>
    Parameters:
    sl - the SkipList to create the span for
    Returns:
    a new SkipSpan instance
  - toString
```
public String toString()
```
    Get a string representation of this span.
    Overrides:
    toString in class Object
    Returns:
    a string representation

Class BSkipSpan<K extends Comparable<? super K>,V>

Field Summary

Fields inherited from class net.metanotion.util.skiplist.SkipSpan

Constructor Summary

Method Summary

Methods inherited from class net.metanotion.util.skiplist.SkipSpan

Methods inherited from class java.lang.Object

Field Detail

bf

CONT_HEADER_LEN

HEADER_LEN

isKilled

keySer

MAGIC

nextPage

overflowPage

page

prevPage

spanSize

valSer

Constructor Detail

BSkipSpan

BSkipSpan

Method Detail

flush

init

killInstance

loadData

loadData

loadInit

lostEntries

newInstance

toString