Package com.google.gwt.user.client.ui

Class PrefixTree

java.lang.Object

java.util.AbstractCollection<String>

com.google.gwt.user.client.ui.PrefixTree

All Implemented Interfaces:

Iterable<String>, Collection<String>

class PrefixTree
extends AbstractCollection<String>

A prefix tree (aka trie).

Field Summary

Fields

Modifier and Type	Field	Description
protected final int	prefixLength	Stores the requested prefix length.
protected int	size	Store the number of elements contained by this PrefixTree and its sub-trees.
protected JavaScriptObject	subtrees	Field to store subtrees in.
protected JavaScriptObject	suffixes	Field to store terminal nodes in.

Constructor Summary

Constructors

Constructor	Description
PrefixTree()	Constructor.
PrefixTree(int prefixLength)	Constructor.
PrefixTree(int prefixLength, Collection<String> source)	Constructor.
PrefixTree(Collection<String> source)	Constructor.

Method Summary

Modifier and Type	Method	Description
boolean	add(String s)	Add a String to the PrefixTree.
void	clear()	Initialize native state.
boolean	contains(Object o)
boolean	contains(String s)
protected static PrefixTree	createPrefixTree(int prefixLength)	Used by native methods to create an appropriately blessed PrefixTree.
List<String>	getSuggestions(String search, int limit)	Retrieve suggestions from the PrefixTree.
Iterator<String>	iterator()
int	size()	Get the number of all elements contained within the PrefixTree.
protected void	suggestImpl(String search, String prefix, Collection<String> output, int limit)

Methods inherited from class java.util.AbstractCollection

addAll, containsAll, isEmpty, remove, removeAll, retainAll, toArray, toArray, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.Collection

equals, hashCode, parallelStream, removeIf, spliterator, stream, toArray

Methods inherited from interface java.lang.Iterable

forEach

Field Details

prefixLength

protected final int prefixLength

Stores the requested prefix length.

suffixes

protected JavaScriptObject suffixes

Field to store terminal nodes in.

subtrees

protected JavaScriptObject subtrees

Field to store subtrees in.

size

protected int size

Store the number of elements contained by this PrefixTree and its sub-trees.

Constructor Details

PrefixTree

public PrefixTree()

Constructor.

PrefixTree

public PrefixTree(Collection<String> source)

Constructor.

Parameters:

source - Initialize from another collection

PrefixTree

public PrefixTree(int prefixLength)

Constructor.

Parameters:

prefixLength - Smaller prefix length equals faster, more direct searches, at a cost of setup time.

PrefixTree

public PrefixTree(int prefixLength,
 Collection<String> source)

Constructor.

Parameters:

prefixLength - Smaller prefix length equals faster, more direct searches, at a cost of setup time.

source - Initialize from another collection

Method Details

createPrefixTree

protected static PrefixTree createPrefixTree(int prefixLength)

Used by native methods to create an appropriately blessed PrefixTree.

Parameters:

prefixLength - Smaller prefix length equals faster, more direct searches, at a cost of setup time

Returns:

a newly constructed prefix tree

add

public boolean add(String s)

Add a String to the PrefixTree.

Specified by:

add in interface Collection<String>

Overrides:

add in class AbstractCollection<String>

Parameters:

s - The data to add

Returns:

true if the string was added, false otherwise

clear

public void clear()

Initialize native state.

Specified by:

clear in interface Collection<String>

Overrides:

clear in class AbstractCollection<String>

contains

public boolean contains(Object o)

Specified by:

contains in interface Collection<String>

Overrides:

contains in class AbstractCollection<String>

contains

public boolean contains(String s)

getSuggestions

public List<String> getSuggestions(String search,
 int limit)

Retrieve suggestions from the PrefixTree. The number of items returned from getSuggestions may slightly exceed limit so that all suffixes and partial stems will be returned. This prevents the search space from changing size if the PrefixTree is used in an interactive manner.
The returned List is guaranteed to be safe; changing its contents will not affect the PrefixTree.

Parameters:

search - The prefix to search for

limit - The desired number of results to retrieve

Returns:

A List of suggestions

iterator

public Iterator<String> iterator()

Specified by:

iterator in interface Collection<String>

Specified by:

iterator in interface Iterable<String>

Specified by:

iterator in class AbstractCollection<String>

size

public int size()

Get the number of all elements contained within the PrefixTree.

Specified by:

size in interface Collection<String>

Specified by:

size in class AbstractCollection<String>

Returns:

the size of the prefix tree

suggestImpl

protected void suggestImpl(String search,
 String prefix,
 Collection<String> output,
 int limit)