Class SnappyLoader

java.lang.Object

org.xerial.snappy.SnappyLoader

public class SnappyLoader
extends Object

Internal only - Do not use this class. This class loads a native library of snappy-java (snappyjava.dll, libsnappy.so, etc.) according to the user platform (os.name and os.arch). The natively compiled libraries bundled to snappy-java contain the codes of the original snappy and JNI programs to access Snappy.

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.) in the following order:

1. If system property org.xerial.snappy.use.systemlib is set to true, lookup folders specified by java.lib.path system property (This is the default path that JVM searches for native libraries)
2. (System property: org.xerial.snappy.lib.path)/(System property: org.xerial.lib.name)
3. One of the libraries embedded in snappy-java-(version).jar extracted into (System property: java.io.tmpdir). If org.xerial.snappy.tempdir is set, use this folder instead of java.io.tmpdir.

If you do not want to use folder java.io.tmpdir, set the System property org.xerial.snappy.tempdir. For example, to use /tmp/leo as a temporary folder to copy native libraries, use -D option of JVM:

java -Dorg.xerial.snappy.tempdir="/tmp/leo" ...

Field Summary

Fields

Modifier and Type	Field	Description
private static BitShuffleNative	bitshuffleApi
private static boolean	isLoaded
static final String	KEY_SNAPPY_DISABLE_BUNDLED_LIBS
static final String	KEY_SNAPPY_LIB_NAME
static final String	KEY_SNAPPY_LIB_PATH
static final String	KEY_SNAPPY_PUREJAVA
static final String	KEY_SNAPPY_TEMPDIR
static final String	KEY_SNAPPY_USE_SYSTEMLIB
private static File	nativeLibFile
static final String	SNAPPY_SYSTEM_PROPERTIES_FILE
private static SnappyApi	snappyApi

Constructor Summary

Constructors

Constructor	Description
SnappyLoader()

Method Summary

Modifier and Type	Method	Description
(package private) static void	cleanUpExtractedNativeLib()
private static boolean	contentsEquals(InputStream in1, InputStream in2)
private static File	extractLibraryFile(String libFolderForCurrentOS, String libraryFileName, String targetFolder)	Extract the specified library file to the target folder
(package private) static File	findNativeLibrary()
private static InputStream	getResourceAsInputStream(String resourcePath)
static String	getVersion()	Get the snappy-java version by reading pom.properties embedded in jar.
private static boolean	hasResource(String path)
(package private) static BitShuffleNative	loadBitShuffleApi()
private static void	loadNativeLibrary()	Load a native library of snappy-java
(package private) static SnappyApi	loadSnappyApi()
private static void	loadSnappySystemProperties()	load system properties when configuration file of the name SNAPPY_SYSTEM_PROPERTIES_FILE is found
(package private) static void	setSnappyApi(SnappyApi apiImpl)	Set the `snappyApi` instance.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

SNAPPY_SYSTEM_PROPERTIES_FILE

public static final String SNAPPY_SYSTEM_PROPERTIES_FILE

See Also:

• Constant Field Values

KEY_SNAPPY_LIB_PATH

public static final String KEY_SNAPPY_LIB_PATH

See Also:

• Constant Field Values

KEY_SNAPPY_LIB_NAME

public static final String KEY_SNAPPY_LIB_NAME

See Also:

• Constant Field Values

KEY_SNAPPY_PUREJAVA

public static final String KEY_SNAPPY_PUREJAVA

See Also:

• Constant Field Values

KEY_SNAPPY_TEMPDIR

public static final String KEY_SNAPPY_TEMPDIR

See Also:

• Constant Field Values

KEY_SNAPPY_USE_SYSTEMLIB

public static final String KEY_SNAPPY_USE_SYSTEMLIB

See Also:

• Constant Field Values

KEY_SNAPPY_DISABLE_BUNDLED_LIBS

public static final String KEY_SNAPPY_DISABLE_BUNDLED_LIBS

See Also:

• Constant Field Values

isLoaded

private static boolean isLoaded

snappyApi

private static volatile SnappyApi snappyApi

bitshuffleApi

private static volatile BitShuffleNative bitshuffleApi

nativeLibFile

private static File nativeLibFile

Constructor Details

SnappyLoader

public SnappyLoader()

Method Details

cleanUpExtractedNativeLib

static void cleanUpExtractedNativeLib()

setSnappyApi

static void setSnappyApi(SnappyApi apiImpl)

Set the `snappyApi` instance.

Parameters:

apiImpl -

loadSnappySystemProperties

private static void loadSnappySystemProperties()

load system properties when configuration file of the name SNAPPY_SYSTEM_PROPERTIES_FILE is found

loadSnappyApi

static SnappyApi loadSnappyApi()

loadBitShuffleApi

static BitShuffleNative loadBitShuffleApi()

loadNativeLibrary

private static void loadNativeLibrary()

Load a native library of snappy-java

contentsEquals

private static boolean contentsEquals(InputStream in1,
 InputStream in2)
                               throws IOException

Throws:

IOException

extractLibraryFile

private static File extractLibraryFile(String libFolderForCurrentOS,
 String libraryFileName,
 String targetFolder)

Extract the specified library file to the target folder

Parameters:

libFolderForCurrentOS -

libraryFileName -

targetFolder -

Returns:

findNativeLibrary

static File findNativeLibrary()

hasResource

private static boolean hasResource(String path)

getVersion

public static String getVersion()

Get the snappy-java version by reading pom.properties embedded in jar. This version data is used as a suffix of a dll file extracted from the jar.

Returns:

the version string

getResourceAsInputStream

private static InputStream getResourceAsInputStream(String resourcePath)
                                             throws IOException

Throws:

IOException