Package org.elasticsearch.common.util

Class BytesRefHash

java.lang.Object

org.elasticsearch.common.util.BytesRefHash

All Implemented Interfaces:

Closeable, AutoCloseable, Releasable

public final class BytesRefHash
extends Object

Specialized hash table implementation similar to Lucene's BytesRefHash that maps BytesRef values to ids. Collisions are resolved with open addressing and linear probing, growth is smooth thanks to BigArrays, hashes are cached for faster re-hashing and capacity is always a multiple of 2 for faster identification of buckets. This class is not thread-safe.

Constructor Summary

Constructors

Constructor	Description
BytesRefHash(long capacity, float maxLoadFactor, BigArrays bigArrays)
BytesRefHash(long capacity, BigArrays bigArrays)

Method Summary

Modifier and Type	Method	Description
long	add(BytesRef key)	Sugar to add(key, key.hashCode().
long	add(BytesRef key, int code)	Try to add key.
long	capacity()	Return the number of allocated slots to store this hash table.
void	close()
long	find(BytesRef key)	Sugar for find(key, key.hashCode()
long	find(BytesRef key, int code)	Get the id associated with key
BytesRef	get(long id, BytesRef dest)	Return the key at 0 <= index <= capacity().
protected void	grow()
long	id(long index)	Get the id associated with key at 0 <= index <= capacity() or -1 if this slot is unused.
protected long	id(long index, long id)
protected void	removeAndAdd(long index)	Remove the entry at the given index and add it back
protected void	resize(long capacity)	Resize to the given capacity.
long	size()	Return the number of longs in this hash table.
protected boolean	used(long bucket)

Methods inherited from class java.lang.Object

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

Constructor Detail

BytesRefHash

public BytesRefHash(long capacity,
                    BigArrays bigArrays)

BytesRefHash

public BytesRefHash(long capacity,
                    float maxLoadFactor,
                    BigArrays bigArrays)

Method Detail

get

public BytesRef get(long id,
                    BytesRef dest)

Return the key at 0 <= index <= capacity(). The result is undefined if the slot is unused.

Beware that the content of the BytesRef may become invalid as soon as close() is called

find

public long find(BytesRef key,
                 int code)

Get the id associated with key

find

public long find(BytesRef key)

Sugar for find(key, key.hashCode()

add

public long add(BytesRef key,
                int code)

Try to add key. Return its newly allocated id if it wasn't in the hash table yet, or -1-id if it was already present in the hash table.

add

public long add(BytesRef key)

Sugar to add(key, key.hashCode().

removeAndAdd

protected void removeAndAdd(long index)

Remove the entry at the given index and add it back

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface Releasable

id

public long id(long index)

Get the id associated with key at 0 <= index <= capacity() or -1 if this slot is unused.

id

protected final long id(long index,
                        long id)

resize

protected void resize(long capacity)

Resize to the given capacity.

used

protected boolean used(long bucket)

capacity

public long capacity()

Return the number of allocated slots to store this hash table.

size

public long size()

Return the number of longs in this hash table.

grow

protected final void grow()