org.eclipse.jetty.util

Class ArrayTernaryTrie<V>

java.lang.Object

org.eclipse.jetty.util.AbstractTrie<V>

org.eclipse.jetty.util.ArrayTernaryTrie<V>

Type Parameters:

V -

All Implemented Interfaces:

Trie<V>

public class ArrayTernaryTrie<V>
extends AbstractTrie<V>

A Ternary Trie String lookup data structure. This Trie is of a fixed size and cannot grow (which can be a good thing with regards to DOS when used as a cache).

The Trie is stored in 3 arrays:

char[] _tree

This is semantically 2 dimensional array flattened into a 1 dimensional char array. The second dimension is that every 4 sequential elements represents a row of: character; hi index; eq index; low index, used to build a ternary trie of key strings.

String[] _key

An array of key values where each element matches a row in the _tree array. A non zero key element indicates that the _tree row is a complete key rather than an intermediate character of a longer key.

V[] _value

An array of values corresponding to the _key array

The lookup of a value will iterate through the _tree array matching characters. If the equal tree branch is followed, then the _key array is looked up to see if this is a complete match. If a match is found then the _value array is looked up to return the matching value.

Constructor Summary

Constructors

Constructor and Description
ArrayTernaryTrie()
ArrayTernaryTrie(ArrayTernaryTrie<V> trie, double factor) Copy Trie and change capacity by a factor
ArrayTernaryTrie(boolean insensitive)
ArrayTernaryTrie(boolean insensitive, int capacityInNodes)
ArrayTernaryTrie(int capacityInNodes)

Method Summary

Methods

Modifier and Type	Method and Description
void	dump()
V	get(ByteBuffer b, int offset, int len) Get and exact match from a segment of a ByteBuufer as key
V	get(String s, int offset, int len) Get and exact match from a String key
V	getBest(ByteBuffer b, int offset, int len) Get the best match from key in a byte buffer.
V	getBest(String s) Get the best match from key in a String.
V	getBest(String s, int offset, int length) Get the best match from key in a String.
static int	hilo(int diff)
boolean	isFull()
Set<String>	keySet()
boolean	put(String s, V v) Put and entry into the Trie
String	toString()

Methods inherited from class org.eclipse.jetty.util.AbstractTrie

get, get, getBest, isCaseInsensitive, put, remove

Methods inherited from class java.lang.Object

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

Constructor Detail

ArrayTernaryTrie

public ArrayTernaryTrie()

ArrayTernaryTrie

public ArrayTernaryTrie(boolean insensitive)

ArrayTernaryTrie

public ArrayTernaryTrie(int capacityInNodes)

ArrayTernaryTrie

public ArrayTernaryTrie(boolean insensitive,
                int capacityInNodes)

ArrayTernaryTrie

public ArrayTernaryTrie(ArrayTernaryTrie<V> trie,
                double factor)

Copy Trie and change capacity by a factor

Parameters:

trie -

factor -

Method Detail

put

public boolean put(String s,
          V v)

Description copied from interface: Trie

Put and entry into the Trie

Parameters:

s - The key for the entry

v - The value of the entry

Returns:

True if the Trie had capacity to add the field.

get

public V get(String s,
    int offset,
    int len)

Description copied from interface: Trie

Get and exact match from a String key

Parameters:

s - The key

offset - The offset within the string of the key

len - the length of the key

Returns:

get

public V get(ByteBuffer b,
    int offset,
    int len)

Description copied from interface: Trie

Get and exact match from a segment of a ByteBuufer as key

Parameters:

b - The buffer

offset - The offset within the buffer of the key

len - the length of the key

Returns:

The value or null if not found

getBest

public V getBest(String s)

Description copied from interface: Trie

Get the best match from key in a String.

Specified by:

getBest in interface Trie<V>

Overrides:

getBest in class AbstractTrie<V>

Parameters:

s - The string

Returns:

The value or null if not found

getBest

public V getBest(String s,
        int offset,
        int length)

Description copied from interface: Trie

Get the best match from key in a String.

Parameters:

s - The string

offset - The offset within the string of the key

length - the length of the key

Returns:

The value or null if not found

getBest

public V getBest(ByteBuffer b,
        int offset,
        int len)

Description copied from interface: Trie

Get the best match from key in a byte buffer. The key is assumed to by ISO_8859_1 characters.

Parameters:

b - The buffer

offset - The offset within the buffer of the key

len - the length of the key

Returns:

The value or null if not found

toString

public String toString()

Overrides:

toString in class Object

keySet

public Set<String> keySet()

isFull

public boolean isFull()

hilo

public static int hilo(int diff)

dump

public void dump()