PrefixMap : Implementation

A datastructure the allows looking up the best matching prefix.

License	Apache License, Version 2.0
GroupId	nl.basjes.collections
ArtifactId	prefixmap
Last Version	2.0
Release Date	Nov 22, 2020
Type	jar
Description	PrefixMap : Implementation A datastructure the allows looking up the best matching prefix.
Project URL	https://github.com/nielsbasjes/prefixmap
Source Code Management	https://github.com/nielsbasjes/prefixmap

Download prefixmap

Filename	Size
prefixmap-2.0.pom
prefixmap-2.0.jar	13 KB
prefixmap-2.0-sources.jar	8 KB
prefixmap-2.0-javadoc.jar	46 KB

How to add to project

Apache Maven

<!-- https://jarcasting.com/artifacts/nl.basjes.collections/prefixmap/ -->
<dependency>
    <groupId>nl.basjes.collections</groupId>
    <artifactId>prefixmap</artifactId>
    <version>2.0</version>
</dependency>

Gradle Groovy

// https://jarcasting.com/artifacts/nl.basjes.collections/prefixmap/
implementation 'nl.basjes.collections:prefixmap:2.0'

Gradle Kotlin

// https://jarcasting.com/artifacts/nl.basjes.collections/prefixmap/
implementation ("nl.basjes.collections:prefixmap:2.0")

Apache Buildr

'nl.basjes.collections:prefixmap:jar:2.0'

Apache Ivy

<dependency org="nl.basjes.collections" name="prefixmap" rev="2.0">
  <artifact name="prefixmap" type="jar" />
</dependency>

Groovy Grape

@Grapes(
@Grab(group='nl.basjes.collections', module='prefixmap', version='2.0')
)

Scala SBT

libraryDependencies += "nl.basjes.collections" % "prefixmap" % "2.0"

Leiningen

[nl.basjes.collections/prefixmap "2.0"]

Dependencies

provided (1)

Group / Artifact	Type	Version
com.esotericsoftware : kryo	jar	5.0.0-RC9

test (3)

Group / Artifact	Type	Version
org.junit.jupiter : junit-jupiter-engine	jar
org.slf4j : slf4j-api	jar	1.7.30
org.slf4j : slf4j-log4j12	jar	1.7.30

Project Modules

There are no modules declared in this project.

PrefixMap: A Map type datastructure that uses prefixes instead of keys

This is a java library that implements a datastructure I consider to be missing in the java landscape.

The datastructure and its usages

In several situations I have a set of values that are each associated with a different prefix of a String.

The example where I found the biggest need for this was when analyzing the device tags of mobile devices.

• A "GT-I8190N" is a "Samsung" device because it starts with "GT-".
• A "RM-1092" is a "Nokia" device because it starts with "RM-".

So I needed a lookup structure that maps these prefixes to the desired brands.

"GT-" : "Samsung"
"RM-" : "Nokia"

With this code you can now do this type of lookup in a very fast way:

// Parameter caseSensitive=false --> so lookups are caseINsensitive
PrefixMap<String> brandLookup = new StringPrefixMap<>(false);

brandLookup.put("GT-", "Samsung");
brandLookup.put("RM-", "Nokia");

String brandGT = brandLookup.getLongestMatch("GT-I8190N");   // --> "Samsung"
String brandRM = brandLookup.getLongestMatch("RM-1092");     // --> "Nokia"

All you need is to add this dependency to you project

<dependency>
  <groupId>nl.basjes.collections</groupId>
  <artifactId>prefixmap</artifactId>
  <version>2.0</version>
</dependency>

Version 2.0 If you are using Kryo 5.x you can use this to register all classes:

StringPrefixMap.configureKryo(kryo);

Blog post

A bit more background about this datastructure and how it works can be found in this blog which I wrote about it: https://techlab.bol.com/finding-the-longest-matching-string-prefix-fast/ (Local copy)

Donations

If this project has business value for you then don't hesitate to support me with a small donation.

License

Copyright (C) 2018-2020 Niels Basjes

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

https://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

Versions

Version
2.0 Nov 22, 2020
1.2 Jul 4, 2020
1.1 Jan 26, 2019
1.0 Jan 13, 2019