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This document is a copy of http://code.google.com/p/snappy-java/
---------------------------------------
The snappy-java is a Java port of the snappy http://code.google.com/p/snappy/, a fast compresser/decompresser written in C++ developed by Google.
== Features ==
* [http://www.apache.org/licenses/LICENSE-2.0 Apache Licence Version 2.0]. Free for both commercial and non-commercial use.
* Fast compression/decompression tailored to 64-bit CPU architecture.
* JNI-based implementation to achieve comparable performance to the native C++ version.
* Although snappy-java uses JNI, it can be used safely with multiple class loaders (e.g. Tomcat, etc.).
* Portable across various operating systems; Snappy-java contains native libraries built for Window/Mac/Linux (32/64-bit). At runtime, snappy-java loads one of these libraries according to your machine environment (It looks system properties, `os.name` and `os.arch`).
* Simple usage. Add the snappy-java-(version).jar file to your classpath. Then call compression/decompression methods in org.xerial.snappy.Snappy.
== Performance ==
* Snappy's main target is very high-speed compression/decompression with reasonable compression size. So the compression ratio of snappy-java is modest and about the same as `LZF` (ranging 20%-100% according to the dataset).
* Here are some [https://github.com/ning/jvm-compressor-benchmark/wiki benchmark results], comparing snappy-java and the other compressors `LZO-java`/`LZF`/`QuickLZ`/`Gzip`/`Bzip2`. Thanks [http://twitter.com/#!/cowtowncoder Tatu Saloranta @cowtowncoder] for providing the benchmark suite.
* The benchmark result indicates snappy-java is the fastest compreesor/decompressor in Java:
* http://ning.github.com/jvm-compressor-benchmark/results/canterbury-roundtrip-2011-07-28/index.html
* The decompression speed is twice as fast as the others:
* http://ning.github.com/jvm-compressor-benchmark/results/canterbury-uncompress-2011-07-28/index.html
== Download ==
The current stable version 1.0.3.1 is available from here:
* Release version: http://maven.xerial.org/repository/artifact/org/xerial/snappy/snappy-java
* [Milestone] release plans
* Snapshot version (the latest beta version): http://maven.xerial.org/repository/snapshot/org/xerial/snappy/snappy-java/
If you are a Maven user, see [#Using_with_Maven]
== Usage ==
First, import `org.xerial.snapy.Snappy` in your Java code:
{{{
import org.xerial.snappy.Snappy;
}}}
Then use `Snappy.compress(byte[])` and `Snappy.uncompress(byte[])`:
{{{
String input = "Hello snappy-java! Snappy-java is a JNI-based wrapper of "
+ "Snappy, a fast compresser/decompresser.";
byte[] compressed = Snappy.compress(input.getBytes("UTF-8"));
byte[] uncompressed = Snappy.uncompress(compressed);
String result = new String(uncompressed, "UTF-8");
System.out.println(result);
}}}
In addition, high-level methods (`Snappy.compress(String)`, `Snappy.compress(float[] ..)` etc. ) and low-level ones (e.g. `Snappy.rawCompress(.. )`, `Snappy.rawUncompress(..)`, etc.), which minimize memory copies, can be used. See also
[http://code.google.com/p/snappy-java/source/browse/src/main/java/org/xerial/snappy/Snappy.java Snappy.java]
===Stream-based API===
Stream-based compressor/decompressor `SnappyOutputStream`/`SnappyInputStream` are also available for reading/writing large data sets.
===Setting classpath==
If you have snappy-java-(VERSION).jar in the current directory, use `-classpath` option as follows:
{{{
$ javac -classpath ".;snappy-java-(VERSION).jar" Sample.java # in Windows
or
$ javac -classpath ".:snappy-java-(VERSION).jar" Sample.java # in Mac or Linux
}}}
===Using with Maven===
* Snappy-java is available from Maven's central repository: http://repo1.maven.org/maven2/org/xerial/snappy/snappy-java
Add the following dependency to your pom.xml:
{{{
<dependency>
<groupId>org.xerial.snappy</groupId>
<artifactId>snappy-java</artifactId>
<version>(version)</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
}}}
==Public discussion group==
Post bug reports or feature request to the Issue Tracker: http://code.google.com/p/snappy-java/issues/list
Public discussion forum is here: [http://groups.google.com/group/xerial?hl=en Xerial Public Discussion Group].
== Building from the source code ==
See the [http://code.google.com/p/snappy-java/source/browse/INSTALL installation instruction]. Building from the source code is an option when your OS platform and CPU architecture is not supported. To build snappy-java, you need Mercurial(hg), JDK (1.6 or higher), Maven (3.x or higher is required), g++ compiler (mingw in Windows) etc.
{{{
$ hg clone https://snappy-java.googlecode.com/hg/ snappy-java
$ cd snappy-java
$ make
}}}
A file `target/snappy-java-$(version).jar` is the product additionally containing the native library built for your platform.
==Miscellaneous Notes==
===Using snappy-java with Tomcat 6 (or higher) Web Server===
Simply put the snappy-java's jar to WEB-INF/lib folder of your web application. Usual JNI-library specific problem no longer exists since snappy-java version 1.0.3 or higher can be loaded by multiple class loaders in the same JVM by using native code injection to the parent class loader (Issue 21).
----
Snappy-java is developed by [http://www.xerial.org/leo Taro L. Saito]. Twitter [http://twitter.com/#!/taroleo @taroleo]
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