Updates issue 20. Add org.xerial.snappy.use.systemlib property to lookup snappyjava dll under java.library.path

INSTALL

@@ -56,9 +56,9 @@ $ make clean-native native
 
 = Using system installed libsnappyjava (or snappyjava.dll) 
 
-Use org.xerial.snappy.enable.bundled.libs system property:
+Set org.xerial.snappy.use.systemlib system property to true:
 
-java -Djava.library.path=(path to the installed snappyjava lib) -Dorg.xerial.snappy.enable.bundled.libs=false  ...
+java -Djava.library.path=(path to the installed snappyjava lib) -Dorg.xerial.snappy.use.systemlib=true  ...
 
 With this setting snappy-java does not use bundled native libraries. Insted it tries to load native library installed at the path specified in java.library.path.
 

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

@@ -51,8 +51,8 @@ import java.util.Properties;
  * In default, no configuration is required to use snappy-java, but you can load
  * your own native library created by 'make native' command.
  * 
- * This SnappyLoader searches for native libraries (snappyjava.dll, libsnappy.so, etc.)
+ * This SnappyLoader searches for native libraries (snappyjava.dll,
- * in the following order:
+ * libsnappy.so, etc.) in the following order:
  * <ol>
  * <li>(System property: <i>org.xerial.snappy.lib.path</i>)/(System property:
  * <i>org.xerial.lib.name</i>)
@@ -85,7 +85,8 @@ public class SnappyLoader
     public static final String     KEY_SNAPPY_LIB_PATH             = "org.xerial.snappy.lib.path";
     public static final String     KEY_SNAPPY_LIB_NAME             = "org.xerial.snappy.lib.name";
     public static final String     KEY_SNAPPY_TEMPDIR              = "org.xerial.snappy.tempdir";
-    public static final String     KEY_SNAPPY_ENABLE_BUNDLED_LIBS = "org.xerial.snappy.enable.bundled.libs";
+    public static final String     KEY_SNAPPY_USE_SYSTEMLIB        = "org.xerial.snappy.use.systemlib";
+    public static final String     KEY_SNAPPY_DISABLE_BUNDLED_LIBS = "org.xerial.snappy.disable.bundled.libs"; // Depreciated, but preserved for backward compatibility
 
     private static boolean         isLoaded                        = false;
     private static SnappyNativeAPI api                             = null;
@@ -132,8 +133,9 @@ public class SnappyLoader
 
     /**
      * Load SnappyNative and its JNI native implementation in the root class
-     * loader. This process is necessary to avoid the JNI multi-loading issue when the
+     * loader. This process is necessary to avoid the JNI multi-loading issue
-     * same JNI library is loaded by different class loaders in the same JVM.
+     * when the same JNI library is loaded by different class loaders in the
+     * same JVM.
      * 
      * In order to load native code in the root class loader, this method first
      * inject SnappyNativeLoader class into the root class loader, because
@@ -361,11 +363,20 @@ public class SnappyLoader
     }
 
     static File findNativeLibrary() {
-        // Try to load the library from org.xerial.snappy.lib.path library path */
+
+        boolean useSystemLib = Boolean.parseBoolean(System.getProperty(KEY_SNAPPY_USE_SYSTEMLIB, "false"));
+        if (useSystemLib)
+            return null;
+
+        boolean disabledBundledLibs = Boolean
+                .parseBoolean(System.getProperty(KEY_SNAPPY_DISABLE_BUNDLED_LIBS, "false"));
+        if (disabledBundledLibs)
+            return null;
+
+        // Try to load the library in org.xerial.snappy.lib.path  */
         String snappyNativeLibraryPath = System.getProperty(KEY_SNAPPY_LIB_PATH);
         String snappyNativeLibraryName = System.getProperty(KEY_SNAPPY_LIB_NAME);
 
-        if (System.getProperty(KEY_SNAPPY_ENABLE_BUNDLED_LIBS, "true").equals("true")) {
         // Resolve the library file name with a suffix (e.g., dll, .so, etc.) 
         if (snappyNativeLibraryName == null)
             snappyNativeLibraryName = System.mapLibraryName("snappyjava");
@@ -389,7 +400,6 @@ public class SnappyLoader
                 return extractLibraryFile(snappyNativeLibraryPath, snappyNativeLibraryName, tempFolder);
             }
         }
-        }
 
         return null; // Use a pre-installed snappyjava
     }

src/test/java/org/xerial/snappy/SnappyLoaderTest.java

@@ -117,7 +117,7 @@ public class SnappyLoaderTest
 
     public static void main(String[] args) {
         // Test for loading native library specified in -Djava.library.path
-        System.setProperty(SnappyLoader.KEY_SNAPPY_ENABLE_BUNDLED_LIBS, "false");
+        System.setProperty(SnappyLoader.KEY_SNAPPY_USE_SYSTEMLIB, "true");
         _logger.debug(Snappy.getNativeLibraryVersion());
     }
 }