Remove pure-java support (#381)

* Remove pure-java snappy support

* Remove pure-java support description

Author: xerial

README.md

@@ -13,7 +13,6 @@ snappy-java is a Java port of the [snappy](https://github.com/google/snappy), a
   * Compression/decompression of Java primitive arrays (`float[]`, `double[]`, `int[]`, `short[]`, `long[]`, etc.)
      * To improve the compression ratios of these arrays, you can use a fast data-rearrangement implementation ([`BitShuffle`](https://oss.sonatype.org/service/local/repositories/releases/archive/org/xerial/snappy/snappy-java/1.1.8/snappy-java-1.1.8-javadoc.jar/!/org/xerial/snappy/BitShuffle.html)) before compression
   * Portable across various operating systems; Snappy-java contains native libraries built for Window/Mac/Linux, etc. snappy-java loads one of these libraries according to your machine environment (It looks system properties, `os.name` and `os.arch`).
-     * If no native library for your platform is found, snappy-java will fallback to [pure-java implementation](#using-pure-java-snappy-implementation).
   * Simple usage. Add the snappy-java-(version).jar file to your classpath. Then call compression/decompression methods in `org.xerial.snappy.Snappy`.
   * [Framing-format support](https://github.com/google/snappy/blob/master/framing_format.txt) (Since 1.1.0 version)
   * OSGi support
@@ -173,11 +172,6 @@ A file `target/snappy-java-$(version).jar` is the product additionally containin
 
 ## Miscellaneous Notes
 
-### Using pure-java Snappy implementation
-
-snappy-java can optionally use a pure-java implementation of Snappy based on [aircompressor](https://github.com/airlift/aircompressor/tree/master/src/main/java/io/airlift/compress/snappy). This implementation is selected when no native Snappy library for your platform is found. You can also force using this pure-java implementation by setting a JVM property `org.xerial.snappy.purejava=true` before loading any class of Snappy (e.g., using `-Dorg.xerial.snappy.purejava=true` option when launching JVM).
-
-
 ### 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.

build.sbt

@@ -73,7 +73,7 @@ enablePlugins(SbtOsgi)
 
 osgiSettings
 
-OsgiKeys.exportPackage := Seq("org.xerial.snappy", "org.xerial.snappy.buffer", "org.xerial.snappy.pool", "org.xerial.snappy.pure")
+OsgiKeys.exportPackage := Seq("org.xerial.snappy", "org.xerial.snappy.buffer", "org.xerial.snappy.pool")
 OsgiKeys.bundleSymbolicName := "org.xerial.snappy.snappy-java"
 OsgiKeys.bundleActivator := Option("org.xerial.snappy.SnappyBundleActivator")
 OsgiKeys.importPackage := Seq("""org.osgi.framework;version="[1.5,2)"""")

src/main/java/org/xerial/snappy/SnappyLoader.java

@@ -24,8 +24,6 @@
 //--------------------------------------
 package org.xerial.snappy;
 
-import org.xerial.snappy.pure.PureJavaSnappy;
-
 import java.io.*;
 import java.net.URL;
 import java.util.Enumeration;
@@ -149,29 +147,13 @@ private static void loadSnappySystemProperties()
         loadSnappySystemProperties();
     }
 
-    static synchronized boolean isPureJava() {
-        return snappyApi != null && PureJavaSnappy.class.isAssignableFrom(snappyApi.getClass());
-    }
-
     static synchronized SnappyApi loadSnappyApi()
     {
         if (snappyApi != null) {
             return snappyApi;
         }
-        try {
-            if(Boolean.parseBoolean(System.getProperty(KEY_SNAPPY_PUREJAVA, "false"))) {
-                // Use pure-java Snappy implementation
-                setSnappyApi(new PureJavaSnappy());
-            }
-            else {
-                loadNativeLibrary();
-                setSnappyApi(new SnappyNative());
-            }
-        }
-        catch(Throwable e) {
-            // Fall-back to pure-java Snappy implementation
-            setSnappyApi(new PureJavaSnappy());
-        }
+        loadNativeLibrary();
+        setSnappyApi(new SnappyNative());
         return snappyApi;
     }