Package net.metanotion.io.block.index

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

java.lang.Object

net.metanotion.util.skiplist.SkipSpan<K,V>

net.metanotion.io.block.index.BSkipSpan<K,V>

net.metanotion.io.block.index.IBSkipSpan<K,V>

All Implemented Interfaces:

Flushable

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

I2P version of BSkipSpan BSkipSpan stores all keys and values in-memory, backed by the file. IBSkipSpan stores only the first key, and no values, in-memory. For a get(), here we do a linear search through the span in the file and load only the found value (super() does a binary search in-memory). For a put() or remove(), we load all keys and values for the span from the file, make the modification, flush() out the keys and values, and null out the keys and values in-memory. Recommended span size is 16.

Author:

zzz

Field Summary

Fields inherited from class net.metanotion.io.block.index.BSkipSpan

bf, CONT_HEADER_LEN, HEADER_LEN, isKilled, keySer, MAGIC, nextPage, overflowPage, page, prevPage, spanSize, valSer

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

keys, MAX_SIZE, next, nKeys, prev, vals

Constructor Summary

Constructors

Constructor	Description
IBSkipSpan(BlockFile bf, BSkipList<K,V> bsl, int spanPage, Serializer<K> key, Serializer<V> val)

Method Summary

Modifier and Type	Method	Description
K	firstKey()	Does not call super, we always store first key here
void	flush()	Flush to disk and null out in-memory keys and values, saving only the first key
V	get(K key)	Linear search if in file, Binary search if in memory
SkipSpan<K,V>	getSpan(K key, int[] search)	Load whole span from file, do the operation, flush out, then null out in-memory data again.
protected void	loadData()	I2P - second half of load() Load the whole span's keys and values into memory
SkipSpan<K,V>	newInstance(SkipList<K,V> sl)
SkipSpan<K,V>	put(K key, V val, SkipList<K,V> sl)	Load whole span from file, do the operation, flush out, then null out in-memory data again.
Object[]	remove(K key, SkipList<K,V> sl)	Load whole span from file, do the operation, flush out, then null out in-memory data again.
(package private) void	seekAndLoadData()	Seek to the start of the span and load the data Package private so BSkipIterator can call it

Methods inherited from class net.metanotion.io.block.index.BSkipSpan

init, killInstance, loadData, loadInit, lostEntries, toString

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

getEnd, print

Methods inherited from class java.lang.Object

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

Constructor Detail

IBSkipSpan

public IBSkipSpan(BlockFile bf,
                  BSkipList<K,V> bsl,
                  int spanPage,
                  Serializer<K> key,
                  Serializer<V> val)
           throws IOException

Throws:

IOException

Method Detail

newInstance

public SkipSpan<K,V> newInstance(SkipList<K,V> sl)

Overrides:

newInstance in class BSkipSpan<K extends Comparable<? super K>,V>

flush

public void flush()

Flush to disk and null out in-memory keys and values, saving only the first key

Specified by:

flush in interface Flushable

Overrides:

flush in class BSkipSpan<K extends Comparable<? super K>,V>

loadData

protected void loadData()
                 throws IOException

I2P - second half of load() Load the whole span's keys and values into memory

Overrides:

loadData in class BSkipSpan<K extends Comparable<? super K>,V>

Throws:

IOException

seekAndLoadData

void seekAndLoadData()
              throws IOException

Seek to the start of the span and load the data Package private so BSkipIterator can call it

Throws:

IOException

firstKey

public K firstKey()

Does not call super, we always store first key here

Overrides:

firstKey in class SkipSpan<K extends Comparable<? super K>,V>

getSpan

public SkipSpan<K,V> getSpan(K key,
                                   int[] search)

Load whole span from file, do the operation, flush out, then null out in-memory data again. This is called only via SkipList.find()

Overrides:

getSpan in class SkipSpan<K extends Comparable<? super K>,V>

get

public V get(K key)

Linear search if in file, Binary search if in memory

Overrides:

get in class SkipSpan<K extends Comparable<? super K>,V>

put

public SkipSpan<K,V> put(K key,
                               V val,
                               SkipList<K,V> sl)

Load whole span from file, do the operation, flush out, then null out in-memory data again.

Overrides:

put in class SkipSpan<K extends Comparable<? super K>,V>

Returns:

the new span if it caused a split, else null if it went in an existing span

remove

public Object[] remove(K key,
                       SkipList<K,V> sl)

Load whole span from file, do the operation, flush out, then null out in-memory data again.

Overrides:

remove in class SkipSpan<K extends Comparable<? super K>,V>

Returns:

An array of two objects or null. rv[0] is the removed object. rv[1] is the deleted SkipSpan if the removed object was the last in the SkipSpan. rv is null if no object was removed.