com.googlecode.concurrenttrees.radixinverted
Class ConcurrentInvertedRadixTree<O>

java.lang.Object
  com.googlecode.concurrenttrees.radixinverted.ConcurrentInvertedRadixTree<O>

All Implemented Interfaces:

PrettyPrintable, RadixTree<O>, InvertedRadixTree<O>

public class ConcurrentInvertedRadixTree<O>
extends Object
implements InvertedRadixTree<O>, PrettyPrintable

An implementation of InvertedRadixTree which supports lock-free concurrent reads, and allows items to be added to and to be removed from the tree atomically by background thread(s), without blocking reads.

This implementation is based on ConcurrentRadixTree.

Author:

Niall Gallagher

Constructor Summary

ConcurrentInvertedRadixTree(NodeFactory nodeFactory)
Creates a new ConcurrentInvertedRadixTree which will use the given NodeFactory to create nodes.

ConcurrentInvertedRadixTree(NodeFactory nodeFactory, boolean restrictConcurrency)
Creates a new ConcurrentInvertedRadixTree which will use the given NodeFactory to create nodes.

Method Summary

Iterable<CharSequence>	getClosestKeys(CharSequence candidate) Returns a lazy iterable which returns the set of keys in the tree which are the closest match for the given candidate key.
Iterable<CharSequence>	getKeysContainedIn(CharSequence document) Returns a lazy iterable which returns the set of keys in the tree which are contained in the given document.
Iterable<CharSequence>	getKeysPrefixing(CharSequence document) Returns a lazy iterable which returns the set of keys in the tree which prefix the given document.
Iterable<CharSequence>	getKeysStartingWith(CharSequence prefix) Returns a lazy iterable which returns the set of keys in the tree which start with the given prefix.
Iterable<KeyValuePair<O>>	getKeyValuePairsForClosestKeys(CharSequence candidate) Returns a lazy iterable which returns the set of KeyValuePairs for keys and their associated values in the tree which are the closest match for the given candidate key.
Iterable<KeyValuePair<O>>	getKeyValuePairsForKeysContainedIn(CharSequence document) Returns a lazy iterable which returns the set of KeyValuePairs for keys in the tree which are contained in the given document.
Iterable<KeyValuePair<O>>	getKeyValuePairsForKeysPrefixing(CharSequence document) Returns a lazy iterable which returns the set of KeyValuePairs for keys in the tree which prefix the given document.
Iterable<KeyValuePair<O>>	getKeyValuePairsForKeysStartingWith(CharSequence prefix) Returns a lazy iterable which returns the set of KeyValuePairs for keys and their associated values in the tree, where the keys start with the given prefix.
Node	getNode()
O	getValueForExactKey(CharSequence key) Returns the value associated with the given key (exact match), or returns null if no such value is associated with the key.
Iterable<O>	getValuesForClosestKeys(CharSequence candidate) Returns a lazy iterable which returns the set of values associated with keys in the tree which are the closest match for the given candidate key.
Iterable<O>	getValuesForKeysContainedIn(CharSequence document) Returns a lazy iterable which returns the set of values associated with keys in the tree which are contained in the given document.
Iterable<O>	getValuesForKeysPrefixing(CharSequence document) Returns a lazy iterable which returns the set of values associated with keys in the tree which prefix the given document.
Iterable<O>	getValuesForKeysStartingWith(CharSequence prefix) Returns a lazy iterable which returns the set of values associated with keys in the tree which start with the given prefix.
O	put(CharSequence key, O value) Associates the given value with the given key; replacing any previous value associated with the key.
O	putIfAbsent(CharSequence key, O value) If a value is not already associated with the given key in the tree, associates the given value with the key; otherwise if an existing value is already associated, returns the existing value and does not overwrite it.
boolean	remove(CharSequence key) Removes the value associated with the given key (exact match).
int	size() Counts the number of keys/values stored in the tree.

Methods inherited from class java.lang.Object

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

Constructor Detail

ConcurrentInvertedRadixTree

public ConcurrentInvertedRadixTree(NodeFactory nodeFactory)

Creates a new ConcurrentInvertedRadixTree which will use the given NodeFactory to create nodes.

Parameters:

nodeFactory - An object which creates Node objects on-demand, and which might return node implementations optimized for storing the values supplied to it for the creation of each node

ConcurrentInvertedRadixTree

public ConcurrentInvertedRadixTree(NodeFactory nodeFactory,
                                   boolean restrictConcurrency)

Creates a new ConcurrentInvertedRadixTree which will use the given NodeFactory to create nodes.

Parameters:

nodeFactory - An object which creates Node objects on-demand, and which might return node implementations optimized for storing the values supplied to it for the creation of each node

restrictConcurrency - If true, configures use of a ReadWriteLock allowing concurrent reads, except when writes are being performed by other threads, in which case writes block all reads; if false, configures lock-free reads; allows concurrent non-blocking reads, even if writes are being performed by other threads

Method Detail

put

public O put(CharSequence key,
             O value)

Associates the given value with the given key; replacing any previous value associated with the key. Returns the previous value associated with the key, if any.

This operation is performed atomically.

Specified by:

put in interface RadixTree<O>

Specified by:

put in interface InvertedRadixTree<O>

Parameters:

key - The key with which the specified value should be associated

value - The value to associate with the key, which cannot be null

Returns:

The previous value associated with the key, if there was one, otherwise null

putIfAbsent

public O putIfAbsent(CharSequence key,
                     O value)

If a value is not already associated with the given key in the tree, associates the given value with the key; otherwise if an existing value is already associated, returns the existing value and does not overwrite it.

This operation is performed atomically.

Specified by:

putIfAbsent in interface RadixTree<O>

Specified by:

putIfAbsent in interface InvertedRadixTree<O>

Parameters:

key - The key with which the specified value should be associated

value - The value to associate with the key, which cannot be null

Returns:

The existing value associated with the key, if there was one; otherwise null in which case the new value was successfully associated

remove

public boolean remove(CharSequence key)

Removes the value associated with the given key (exact match). If no value is associated with the key, does nothing.

Specified by:

remove in interface RadixTree<O>

Specified by:

remove in interface InvertedRadixTree<O>

Parameters:

key - The key for which an associated value should be removed

Returns:

True if a value was removed (and therefore was associated with the key), false if no value was associated/removed

getValueForExactKey

public O getValueForExactKey(CharSequence key)

Returns the value associated with the given key (exact match), or returns null if no such value is associated with the key.

Specified by:

getValueForExactKey in interface RadixTree<O>

Specified by:

getValueForExactKey in interface InvertedRadixTree<O>

Parameters:

key - The key with which a sought value might be associated

Returns:

The value associated with the given key (exact match), or null if no value was associated with the key

getKeysStartingWith

public Iterable<CharSequence> getKeysStartingWith(CharSequence prefix)

Returns a lazy iterable which returns the set of keys in the tree which start with the given prefix.

This is inclusive - if the given prefix is an exact match for a key in the tree, that key is also returned.

Specified by:

getKeysStartingWith in interface RadixTree<O>

Parameters:

prefix - A prefix of sought keys in the tree

Returns:

The set of keys in the tree which start with the given prefix, inclusive

getValuesForKeysStartingWith

public Iterable<O> getValuesForKeysStartingWith(CharSequence prefix)

Returns a lazy iterable which returns the set of values associated with keys in the tree which start with the given prefix.

This is inclusive - if the given prefix is an exact match for a key in the tree, the value associated with that key is also returned.

Note that although the same value might originally have been associated with multiple keys, the set returned does not contain duplicates (as determined by the value objects' implementation of #equals(Object)).

Specified by:

getValuesForKeysStartingWith in interface RadixTree<O>

Parameters:

prefix - A prefix of keys in the tree for which associated values are sought

Returns:

The set of values associated with keys in the tree which start with the given prefix, inclusive

getKeyValuePairsForKeysStartingWith

public Iterable<KeyValuePair<O>> getKeyValuePairsForKeysStartingWith(CharSequence prefix)

Returns a lazy iterable which returns the set of KeyValuePairs for keys and their associated values in the tree, where the keys start with the given prefix.

This is inclusive - if the given prefix is an exact match for a key in the tree, the KeyValuePair for that key is also returned.

Specified by:

getKeyValuePairsForKeysStartingWith in interface RadixTree<O>

Parameters:

prefix - A prefix of keys in the tree for which associated KeyValuePairs are sought

Returns:

The set of KeyValuePairs for keys in the tree which start with the given prefix, inclusive

getClosestKeys

public Iterable<CharSequence> getClosestKeys(CharSequence candidate)

Returns a lazy iterable which returns the set of keys in the tree which are the closest match for the given candidate key.

Example:
Tree contains: Ford Focus, Ford Mondeo, BMW M3
getClosestKeys("Ford F150") -> returns Ford Focus, Ford Mondeo

This is inclusive - if the given candidate is an exact match for a key in the tree, that key is also returned.

Specified by:

getClosestKeys in interface RadixTree<O>

Parameters:

candidate - A candidate key

Returns:

The set of keys in the tree which most closely match the candidate key, inclusive

getValuesForClosestKeys

public Iterable<O> getValuesForClosestKeys(CharSequence candidate)

Returns a lazy iterable which returns the set of values associated with keys in the tree which are the closest match for the given candidate key.

See {#getClosestKeys} for more details.

Specified by:

getValuesForClosestKeys in interface RadixTree<O>

Parameters:

candidate - A candidate key

Returns:

The set of values associated with keys in the tree which most closely match the candidate key, inclusive

getKeyValuePairsForClosestKeys

public Iterable<KeyValuePair<O>> getKeyValuePairsForClosestKeys(CharSequence candidate)

Returns a lazy iterable which returns the set of KeyValuePairs for keys and their associated values in the tree which are the closest match for the given candidate key.

See {#getClosestKeys} for more details.

Specified by:

getKeyValuePairsForClosestKeys in interface RadixTree<O>

Parameters:

candidate - A candidate key

Returns:

The set of KeyValuePairs for keys and their associated values in the tree which most closely match the candidate key, inclusive

getKeysPrefixing

public Iterable<CharSequence> getKeysPrefixing(CharSequence document)

Returns a lazy iterable which returns the set of keys in the tree which prefix the given document.

Specified by:

getKeysPrefixing in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree which prefix the given document

Returns:

The set of keys in the tree which prefix the given document

getValuesForKeysPrefixing

public Iterable<O> getValuesForKeysPrefixing(CharSequence document)

Returns a lazy iterable which returns the set of values associated with keys in the tree which prefix the given document.

Specified by:

getValuesForKeysPrefixing in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree which prefix the given document

Returns:

The set of values associated with keys in the tree which prefix the given document

getKeyValuePairsForKeysPrefixing

public Iterable<KeyValuePair<O>> getKeyValuePairsForKeysPrefixing(CharSequence document)

Returns a lazy iterable which returns the set of KeyValuePairs for keys in the tree which prefix the given document.

Specified by:

getKeyValuePairsForKeysPrefixing in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree which prefix the given document

Returns:

The set of KeyValuePairs for keys in the tree which prefix the given document

getKeysContainedIn

public Iterable<CharSequence> getKeysContainedIn(CharSequence document)

Returns a lazy iterable which returns the set of keys in the tree which are contained in the given document.

Specified by:

getKeysContainedIn in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree

Returns:

The set of keys in the tree which are contained in the given document

getValuesForKeysContainedIn

public Iterable<O> getValuesForKeysContainedIn(CharSequence document)

Returns a lazy iterable which returns the set of values associated with keys in the tree which are contained in the given document.

Specified by:

getValuesForKeysContainedIn in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree

Returns:

The set of values associated with keys in the tree which are contained in the given document

getKeyValuePairsForKeysContainedIn

public Iterable<KeyValuePair<O>> getKeyValuePairsForKeysContainedIn(CharSequence document)

Returns a lazy iterable which returns the set of KeyValuePairs for keys in the tree which are contained in the given document.

Specified by:

getKeyValuePairsForKeysContainedIn in interface InvertedRadixTree<O>

Parameters:

document - A document to be scanned for keys contained in the tree

Returns:

The set of KeyValuePairs for keys in the tree which are contained in the given document

size

public int size()

Counts the number of keys/values stored in the tree.

In the current implementation, this is an expensive operation, having O(n) time complexity.

Specified by:

size in interface RadixTree<O>

Specified by:

size in interface InvertedRadixTree<O>

Returns:

The number of keys/values stored in the tree

getNode

public Node getNode()

Specified by:

getNode in interface PrettyPrintable