com.boylesoftware.cb2.util
Class BTreeMap

java.lang.Object
  com.boylesoftware.cb2.util.BTreeMap

All Implemented Interfaces:

java.io.Serializable

public class BTreeMap

extends java.lang.Object

implements java.io.Serializable

This class allows to associate values with string prefixes. You add elements as to a map, where keys are strings and values are some objects, later you can do lookups by the longest prefix. Here is an example:

You have the folowing elements in your map:

 ab     => 1
 abcd   => 2
 zyx    => 3
 zyxabc => 4
 

Below are results of lookups by various input strings:

 abcdefgh => 2
 abc      => 1
 a        => null
 orange   => null
 zyx      => 3
 zyx_111  => 3
 

This implementation is not thread-safe. In multithread environments access an object of this class has to be synchronized externally.

Version:

$Id: BTreeMap.java,v 1.2 2003/09/17 19:16:05 levahim Exp $

Author:

Lev Himmelfarb

See Also:

Serialized Form

Nested Class Summary

protected class

BTreeMap.Entry An entry.

Field Summary

protected java.util.HashMap

top The top level.

Constructor Summary

BTreeMap()
Constructs a new empty map.

Method Summary

void	clear() Clears the map.
protected void	clear(java.util.HashMap level) Clears one level.
java.lang.Object	get(java.lang.String key) Looks up the best value for the specified key.
void	put(java.lang.String prefix, java.lang.Object value) Adds a new value to the map.

Methods inherited from class java.lang.Object

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

Field Detail

top

protected final java.util.HashMap top

The top level. Keys are objects of Character, values are objects of BTreeMap.Entry.

Constructor Detail

BTreeMap

public BTreeMap()

Constructs a new empty map.

Method Detail

put

public void put(java.lang.String prefix,
                java.lang.Object value)

Adds a new value to the map.

Parameters:

prefix - the key.

value - the value.

get

public java.lang.Object get(java.lang.String key)

Looks up the best value for the specified key.

Parameters:

key - the input key to look up a value for.

Returns:

value associated with the longest prefix in the map matching the beginning of the specified key. May return null.

clear

public void clear()

Clears the map.

clear

protected void clear(java.util.HashMap level)

Clears one level.

Parameters:

level - the level.