edu.stanford.nlp.util.concurrent

Class ConcurrentHashIndex<E>

java.lang.Object

java.util.AbstractCollection<E>

edu.stanford.nlp.util.concurrent.ConcurrentHashIndex<E>

Type Parameters:

E - Element type to store

All Implemented Interfaces:

Index<E>, java.io.Serializable, java.lang.Iterable<E>, java.util.Collection<E>, java.util.RandomAccess

public class ConcurrentHashIndex<E>
extends java.util.AbstractCollection<E>
implements Index<E>, java.util.RandomAccess

A fast threadsafe index that supports constant-time lookup in both directions. This index is tuned for circumstances in which readers significantly outnumber writers.

Author:

Spence Green

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	UNKNOWN_ID

Constructor Summary

Constructors

Constructor and Description
ConcurrentHashIndex() Constructor.
ConcurrentHashIndex(int initialCapacity) Constructor.

Method Summary

Modifier and Type	Method and Description
boolean	add(E o)
boolean	addAll(java.util.Collection<? extends E> c)
int	addToIndex(E o) Takes an Object and returns the integer index of the Object.
void	clear()
boolean	contains(java.lang.Object o)
E	get(int i) Gets the object whose index is the integer argument.
int	indexOf(E o) Returns the integer index of the Object in the Index or -1 if the Object is not already in the Index.
int	indexOf(E o, boolean add) Deprecated.
boolean	isLocked() Queries the Index for whether it's locked or not.
java.util.Iterator<E>	iterator()
void	lock() Locks the Index.
java.util.Collection<E>	objects(int[] indices) Looks up the objects corresponding to an array of indices, and returns them in a Collection.
java.util.List<E>	objectsList() Returns a complete List of indexed objects, in the order of their indices.
void	saveToFilename(java.lang.String s) Save the contents of this index into a file.
void	saveToWriter(java.io.Writer out) Save the contents of this index into string form, as part of a larger text-serialization.
int	size() Returns the number of indexed objects.
java.lang.String	toString()
void	unlock() Unlocks the Index.

Methods inherited from class java.util.AbstractCollection

containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream

Field Detail

UNKNOWN_ID

public static final int UNKNOWN_ID

See Also:

Constant Field Values

Constructor Detail

ConcurrentHashIndex

public ConcurrentHashIndex()

Constructor.

ConcurrentHashIndex

public ConcurrentHashIndex(int initialCapacity)

Constructor.

Parameters:

initialCapacity -

Method Detail

get

public E get(int i)

Description copied from interface: Index

Gets the object whose index is the integer argument.

Specified by:

get in interface Index<E>

Parameters:

i - the integer index to be queried for the corresponding argument

Returns:

the object whose index is the integer argument.

indexOf

public int indexOf(E o)

Description copied from interface: Index

Returns the integer index of the Object in the Index or -1 if the Object is not already in the Index. This operation never changes the Index.

Specified by:

indexOf in interface Index<E>

Parameters:

o - The Object whose index is desired.

Returns:

The index of the Object argument. Returns -1 if the object is not in the index.

addToIndex

public int addToIndex(E o)

Description copied from interface: Index

Takes an Object and returns the integer index of the Object. If the object was already in the index, it returns its existing index, otherwise it adds it to the index first. Except if the index is locked, and then it returns -1 if the object is not already in the index.

Specified by:

addToIndex in interface Index<E>

Parameters:

o - the Object whose index is desired.

Returns:

the index of the Object argument. Normally a non-negative integer. Returns -1 if the object is not in the index and the Index is locked.

indexOf

@Deprecated
public int indexOf(E o,
                               boolean add)

Deprecated.

Description copied from interface: Index

Takes an Object and returns the integer index of the Object, perhaps adding it to the index first. Returns -1 if the Object is not in the Index. (Note: indexOf(x, true) is the direct replacement for the number(x) method in the old Numberer class.)

Specified by:

indexOf in interface Index<E>

Parameters:

o - the Object whose index is desired.

add - Whether it is okay to add new items to the index

Returns:

the index of the Object argument. Returns -1 if the object is not in the index or if the Index is locked.

add

public boolean add(E o)

Specified by:

add in interface Index<E>

Specified by:

add in interface java.util.Collection<E>

Overrides:

add in class java.util.AbstractCollection<E>

addAll

public boolean addAll(java.util.Collection<? extends E> c)

Specified by:

addAll in interface Index<E>

Specified by:

addAll in interface java.util.Collection<E>

Overrides:

addAll in class java.util.AbstractCollection<E>

objectsList

public java.util.List<E> objectsList()

Description copied from interface: Index

Returns a complete List of indexed objects, in the order of their indices.

Specified by:

objectsList in interface Index<E>

Returns:

a complete List of indexed objects

objects

public java.util.Collection<E> objects(int[] indices)

Description copied from interface: Index

Looks up the objects corresponding to an array of indices, and returns them in a Collection.

Specified by:

objects in interface Index<E>

Parameters:

indices - An array of indices

Returns:

a Collection of the objects corresponding to the indices argument.

isLocked

public boolean isLocked()

Description copied from interface: Index

Queries the Index for whether it's locked or not.

Specified by:

isLocked in interface Index<E>

Returns:

whether or not the Index is locked

lock

public void lock()

Description copied from interface: Index

Locks the Index. A locked index cannot have new elements added to it (calls to Index.add(E) will leave the Index unchanged and return false).

Specified by:

lock in interface Index<E>

unlock

public void unlock()

Description copied from interface: Index

Unlocks the Index. A locked index cannot have new elements added to it (calls to Index.add(E) will leave the Index unchanged and return false).

Specified by:

unlock in interface Index<E>

saveToWriter

public void saveToWriter(java.io.Writer out)
                  throws java.io.IOException

Description copied from interface: Index

Save the contents of this index into string form, as part of a larger text-serialization.

Specified by:

saveToWriter in interface Index<E>

Parameters:

out - Writer to save to.

Throws:

java.io.IOException - Exception thrown if cannot save.

saveToFilename

public void saveToFilename(java.lang.String s)

Description copied from interface: Index

Save the contents of this index into a file.

Specified by:

saveToFilename in interface Index<E>

Parameters:

s - File name.

iterator

public java.util.Iterator<E> iterator()

Specified by:

iterator in interface java.lang.Iterable<E>

Specified by:

iterator in interface java.util.Collection<E>

Specified by:

iterator in class java.util.AbstractCollection<E>

size

public int size()

Description copied from interface: Index

Returns the number of indexed objects.

Specified by:

size in interface Index<E>

Specified by:

size in interface java.util.Collection<E>

Specified by:

size in class java.util.AbstractCollection<E>

Returns:

the number of indexed objects.

toString

public java.lang.String toString()

Overrides:

toString in class java.util.AbstractCollection<E>

contains

public boolean contains(java.lang.Object o)

Specified by:

contains in interface Index<E>

Specified by:

contains in interface java.util.Collection<E>

Overrides:

contains in class java.util.AbstractCollection<E>

clear

public void clear()

Specified by:

clear in interface Index<E>

Specified by:

clear in interface java.util.Collection<E>

Overrides:

clear in class java.util.AbstractCollection<E>