Persistenthashmap

A disk-based HashMap implementation allowing persistence of data across sessions.

License	BSD 3-Clause
GroupId	com.jamierf
ArtifactId	persistenthashmap
Last Version	1.0
Release Date	Jun 26, 2013
Type	jar
Description	Persistenthashmap A disk-based HashMap implementation allowing persistence of data across sessions.
Project URL	https://github.com/reines/persistenthashmap
Source Code Management	https://github.com/reines/persistenthashmap

Download persistenthashmap

Filename	Size
persistenthashmap-1.0.pom
persistenthashmap-1.0.jar	24 KB
persistenthashmap-1.0-sources.jar	12 KB
persistenthashmap-1.0-javadoc.jar	92 KB

How to add to project

Apache Maven

<!-- https://jarcasting.com/artifacts/com.jamierf/persistenthashmap/ -->
<dependency>
    <groupId>com.jamierf</groupId>
    <artifactId>persistenthashmap</artifactId>
    <version>1.0</version>
</dependency>

Gradle Groovy

// https://jarcasting.com/artifacts/com.jamierf/persistenthashmap/
implementation 'com.jamierf:persistenthashmap:1.0'

Gradle Kotlin

// https://jarcasting.com/artifacts/com.jamierf/persistenthashmap/
implementation ("com.jamierf:persistenthashmap:1.0")

Apache Buildr

'com.jamierf:persistenthashmap:jar:1.0'

Apache Ivy

<dependency org="com.jamierf" name="persistenthashmap" rev="1.0">
  <artifact name="persistenthashmap" type="jar" />
</dependency>

Groovy Grape

@Grapes(
@Grab(group='com.jamierf', module='persistenthashmap', version='1.0')
)

Scala SBT

libraryDependencies += "com.jamierf" % "persistenthashmap" % "1.0"

Leiningen

[com.jamierf/persistenthashmap "1.0"]

Dependencies

compile (3)

Group / Artifact	Type	Version
com.google.code.gson : gson	jar	1.7.1
com.thoughtworks.xstream : xstream	jar	1.3.1
xpp3 : xpp3_min	jar	1.1.4c

test (1)

Group / Artifact	Type	Version
junit : junit	jar	4.8.2

Project Modules

There are no modules declared in this project.

About Persistent-HashMap

The Persistent-HashMap is basically a persistent version of the Java HashMap class.

Warning: It is not under active development, and has not been used in a production environment.

Persistent-HashMap can be found in maven central.

<dependency>
    <groupId>com.jamierf</groupId>
    <artifactId>persistenthashmap</artifactId>
    <version>...</version>
</dependency>

Features

• Implements the Map interface so can be used in the exact same way as a regular HashMap.
• No space needs preallocated.
• Disk space is immediately reclaimed on removing an object.
• No maintenance required to keep the data store clean.
• Caching option that keeps a copy of the map in memory (using a standard HashMap) to speed up access.

Notes

• Because the Map interface does not allow for exceptions being thrown null values are used to indicate an error. As such, the map should not be used to store null values otherwise the behaviour is undefined.
• The Persistent-HashMap is thread-safe, but does not perform file locking. This means the same data store should not be accessed from multiple processes at once otherwise the behaviour is undefined.
• Since objects are written to disk the Persistent-HashMap does not have amazingly good performance. It should only be used when persistence is necesary and performance is not critical.

License

The Persistent-HashMap library is released under the BSD 3-clause license.

Credits

The theory is based on HashStore.

Versions

Version
1.0 Jun 26, 2013