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<h1id="project_title">snappy-java</h1>
<h2id="project_tagline">Snappy compressor/decompressor for Java</h2>
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<p>The snappy-java is a Java port of the snappy
<ahref="http://code.google.com/p/snappy/">http://code.google.com/p/snappy/</a>, a fast C++ compresser/decompresser developed by Google.</p>
<h2>Features</h2>
<ul>
<li>
<ahref="http://www.apache.org/licenses/LICENSE-2.0">Apache License Version 2.0</a>. Free for both commercial and non-commercial use.</li>
<li>Fast compression/decompression tailored to 64-bit CPU architecture. </li>
<li>JNI-based implementation to achieve comparable performance to the native C++ version.<br><ul>
<li>Although snappy-java uses JNI, it can be used safely with multiple class loaders (e.g. Tomcat, etc.). </li>
</ul>
</li>
<li>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, <code>os.name</code> and <code>os.arch</code>). </li>
<li>Simple usage. Add the snappy-java-(version).jar file to your classpath. Then call compression/decompression methods in org.xerial.snappy.Snappy. </li>
</ul><h2>Performance</h2>
<ul>
<li><p>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 <code>LZF</code> (ranging 20%-100% according to the dataset).</p></li>
<li>
<p>Here are some <ahref="https://github.com/ning/jvm-compressor-benchmark/wiki">benchmark results</a>, comparing
snappy-java and the other compressors
<code>LZO-java</code>/<code>LZF</code>/<code>QuickLZ</code>/<code>Gzip</code>/<code>Bzip2</code>. Thanks <ahref="http://twitter.com/#!/cowtowncoder">Tatu Saloranta @cotowncoder</a> for providing the benchmark suite. </p>
<ul>
<li>The benchmark result indicates snappy-java is the fastest compreesor/decompressor in Java:</li>
<li>Snapshot version (the latest beta version): <ahref="https://oss.sonatype.org/content/repositories/snapshots/org/xerial/snappy/snappy-java/">https://oss.sonatype.org/content/repositories/snapshots/org/xerial/snappy/snappy-java/</a>
If you are a Maven user, see <ahref="#using-with-maven">pom.xml example</a>.</li>
</ul><h2>Usage</h2>
<p>First, import <code>org.xerial.snapy.Snappy</code> in your Java code:</p>
<pre><code> import org.xerial.snappy.Snappy;
</code></pre>
<p>Then use <code>Snappy.compress(byte[])</code> and <code>Snappy.uncompress(byte[])</code>:</p>
<pre><code> String input = "Hello snappy-java! Snappy-java is a JNI-based wrapper of "
String result = new String(uncompressed, "UTF-8");
System.out.println(result);
</code></pre>
<p>In addition, high-level methods (<code>Snappy.compress(String)</code>, <code>Snappy.compress(float[] ..)</code> etc. ) and low-level ones (e.g. <code>Snappy.rawCompress(.. )</code>, <code>Snappy.rawUncompress(..)</code>, etc.), which minimize memory copies, can be used. See also
<p>Stream-based compressor/decompressor <code>SnappyOutputStream</code>/<code>SnappyInputStream</code> are also available for reading/writing large data sets.</p>
<h3>Setting classpath</h3>
<p>If you have snappy-java-(VERSION).jar in the current directory, use <code>-classpath</code> option as follows:</p>
<pre><code>$ javac -classpath ".;snappy-java-(VERSION).jar" Sample.java # in Windows
or
$ javac -classpath ".:snappy-java-(VERSION).jar" Sample.java # in Mac or Linux
</code></pre>
<h3>Using with Maven</h3>
<ul>
<li>Snappy-java is available from Maven's central repository: <ahref="http://repo1.maven.org/maven2/org/xerial/snappy/snappy-java">http://repo1.maven.org/maven2/org/xerial/snappy/snappy-java</a>
</li>
</ul><p>Add the following dependency to your pom.xml:</p>
<pre><code><dependency>
<groupId>org.xerial.snappy</groupId>
<artifactId>snappy-java</artifactId>
<version>(version)</version>
<type>jar</type>
<scope>compile</scope>
</dependency>
</code></pre>
<h2>Public discussion group</h2>
<p>Post bug reports or feature request to the Issue Tracker: <ahref="https://github.com/xerial/snappy-java/issues">https://github.com/xerial/snappy-java/issues</a></p>
<p>Public discussion forum is here: </p>
<h2>Building from the source code</h2>
<p>See the <ahref="https://github.com/xerial/snappy-java/blob/develop/INSTALL">installation instruction</a>. Building from the source code is an option when your OS platform and CPU architecture is not supported. To build snappy-java, you need Git, JDK (1.6 or higher), Maven (3.x or higher is required), g++ compiler (mingw in Windows) etc.</p>
<p>A file <code>target/snappy-java-$(version).jar</code> is the product additionally containing the native library built for your platform.</p>
<h2>Cross-compiling for other platforms</h2>
<p>The Makefile contains rules for cross-compiling the native library for other platforms so that the snappy-java JAR can support multiple platforms. For example, to build the native libraries for x86 Linux, x86 and x86-64 Windows, and soft- and hard-float ARM:</p>
<pre><code>$ make linux32 win32 win64 linux-arm linux-armhf
</code></pre>
<p>If you append <code>snappy</code> to the line above, it will also build the native library for the current platform and then build the snappy-java JAR (containing all native libraries built so far).</p>
<p>Of course, you must first have the necessary cross-compilers and development libraries installed for each target CPU and OS. For example, on Ubuntu 12.04 for x86-64, install the following packages for each target:</p>
<p>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. </p>
<hr><p>Snappy-java is developed by <ahref="http://www.xerial.org/leo">Taro L. Saito</a>. Twitter <ahref="http://twitter.com/#!/taroleo">@taroleo</a></p>
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