ChainedScatterTable

org.supermind.crawl
Class ChainedScatterTable

java.lang.Object
  org.supermind.crawl.util.ChainedScatterTable

A fixed-size chained scatter table that implements the clock/second-chance algorithm for purging entries.

Implemented for storing longs. The 16 most significant bits are used as the hashkey, whilst the 48 least significant bits are used as the value.

Nested Class Summary
`static class`	`ChainedScatterTable.Entry`

Field Summary
`protected ChainedScatterTable.Entry[]`	`array`
`protected int`	`clockIndex`
`protected int`	`count`
`protected static java.util.logging.Logger`	`LOG` Logger.
`protected ScatterPurger`	`purger`

Constructor Summary
`ChainedScatterTable(ScatterPurger purger)`

Method Summary
`void`	`clear()`
`boolean`	`contains(long chksm)`
`int`	`find(long obj)`
`protected int`	`getAddressToEvict()` This method has side-effect of incrementing clockIndex.
`protected int`	`hash(long obj)` Use 32 most sig.
`int`	`insert(long value)`
`long`	`reconstitute(int idx, long value)` Reconstitute the full long given an index.

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

Field Detail

protected ChainedScatterTable.Entry[] array

protected int clockIndex

protected int count

protected static java.util.logging.Logger LOG

Logger.

protected ScatterPurger purger

Constructor Detail

public ChainedScatterTable(ScatterPurger purger)

Method Detail

public void clear()

public boolean contains(long chksm)

public int find(long obj)

protected int getAddressToEvict()

This method has side-effect of incrementing clockIndex.

protected int hash(long obj)

Use 32 most sig. bits as hash. Lampson's abbreviated keys technique.

public int insert(long value)

public long reconstitute(int idx,
                         long value)

Reconstitute the full long given an index.