io.netty.util.internal

类 PlatformDependent

java.lang.Object

io.netty.util.internal.PlatformDependent

public final class PlatformDependent
extends java.lang.Object

Utility that detects various properties specific to the current runtime environment, such as Java version and the availability of the sun.misc.Unsafe object.

You can disable the use of sun.misc.Unsafe if you specify the system property io.netty.noUnsafe.

字段概要

字段

限定符和类型	字段和说明
static boolean	BIG_ENDIAN_NATIVE_ORDER

方法概要

方法

限定符和类型	方法和说明
static int	addressSize() Return the address size of the OS. 4 (for 32 bits systems ) and 8 (for 64 bits systems).
static java.nio.ByteBuffer	allocateDirectNoCleaner(int capacity) Allocate a new ByteBuffer with the given capacity.
static long	allocateMemory(long size)
static byte[]	allocateUninitializedArray(int size)
static int	bitMode() Returns the bit mode of the current VM (usually 32 or 64.)
static boolean	canEnableTcpNoDelayByDefault() Returns true if and only if it is fine to enable TCP_NODELAY socket option by default.
static void	copyMemory(byte[] src, int srcIndex, long dstAddr, long length)
static void	copyMemory(long srcAddr, byte[] dst, int dstIndex, long length)
static void	copyMemory(long srcAddr, long dstAddr, long length)
static java.nio.ByteBuffer	directBuffer(long memoryAddress, int size)
static long	directBufferAddress(java.nio.ByteBuffer buffer)
static boolean	directBufferPreferred() Returns true if the platform has reliable low-level direct buffer access API and a user has not specified -Dio.netty.noPreferDirect option.
static void	freeDirectBuffer(java.nio.ByteBuffer buffer) Try to deallocate the specified direct ByteBuffer.
static void	freeDirectNoCleaner(java.nio.ByteBuffer buffer) This method MUST only be called for ByteBuffers that were allocated via allocateDirectNoCleaner(int).
static void	freeMemory(long address)
static byte	getByte(byte[] data, int index)
static byte	getByte(long address)
static java.lang.ClassLoader	getClassLoader(java.lang.Class<?> clazz) Return the ClassLoader for the given Class.
static java.lang.ClassLoader	getContextClassLoader() Return the context ClassLoader for the current Thread.
static int	getInt(byte[] data, int index)
static int	getInt(long address)
static int	getInt(java.lang.Object object, long fieldOffset)
static long	getLong(byte[] data, int index)
static long	getLong(long address)
static short	getShort(byte[] data, int index)
static short	getShort(long address)
static java.lang.ClassLoader	getSystemClassLoader() Return the system ClassLoader.
static java.lang.Throwable	getUnsafeUnavailabilityCause() Return the reason (if any) why sun.misc.Unsafe was not available.
static boolean	hasDirectBufferNoCleanerConstructor()
static boolean	hasUnsafe() Return true if sun.misc.Unsafe was found on the classpath and can be used for accelerated direct memory access.
static boolean	isAndroid() Returns true if and only if the current platform is Android
static boolean	isOsx() Return true if the JVM is running on OSX / MacOS
static boolean	isUnaligned() true if and only if the platform supports unaligned access.
static boolean	isWindows() Return true if the JVM is running on Windows
static boolean	isZero(byte[] bytes, int startPos, int length) Determine if a subsection of an array is zero.
static int	javaVersion() Return the version of Java under which this library is used.
static long	maxDirectMemory() Returns the maximum memory reserved for direct buffer allocation.
static boolean	maybeSuperUser() Return true if the current user may be a super-user.
static <C> java.util.Deque<C>	newConcurrentDeque() Returns a new concurrent Deque.
static <K,V> java.util.concurrent.ConcurrentMap<K,V>	newConcurrentHashMap() Creates a new fastest ConcurrentMap implementation for the current platform.
static <K,V> java.util.concurrent.ConcurrentMap<K,V>	newConcurrentHashMap(int initialCapacity) Creates a new fastest ConcurrentMap implementation for the current platform.
static <K,V> java.util.concurrent.ConcurrentMap<K,V>	newConcurrentHashMap(int initialCapacity, float loadFactor) Creates a new fastest ConcurrentMap implementation for the current platform.
static <K,V> java.util.concurrent.ConcurrentMap<K,V>	newConcurrentHashMap(int initialCapacity, float loadFactor, int concurrencyLevel) Creates a new fastest ConcurrentMap implementation for the current platform.
static <K,V> java.util.concurrent.ConcurrentMap<K,V>	newConcurrentHashMap(java.util.Map<? extends K,? extends V> map) Creates a new fastest ConcurrentMap implementation for the current platform.
static <T> java.util.Queue<T>	newFixedMpscQueue(int capacity) Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!)
static LongCounter	newLongCounter() Creates a new fastest LongCounter implementation for the current platform.
static <T> java.util.Queue<T>	newMpscQueue() Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).
static <T> java.util.Queue<T>	newMpscQueue(int maxCapacity) Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).
static <T> java.util.Queue<T>	newSpscQueue() Create a new Queue which is safe to use for single producer (one thread!)
static java.lang.String	normalizedArch()
static java.lang.String	normalizedOs()
static void	putByte(byte[] data, int index, byte value)
static void	putByte(long address, byte value)
static void	putInt(byte[] data, int index, int value)
static void	putInt(long address, int value)
static void	putLong(byte[] data, int index, long value)
static void	putLong(long address, long value)
static void	putShort(byte[] data, int index, short value)
static void	putShort(long address, short value)
static java.nio.ByteBuffer	reallocateDirectNoCleaner(java.nio.ByteBuffer buffer, int capacity) Reallocate a new ByteBuffer with the given capacity.
static void	setMemory(byte[] dst, int dstIndex, long bytes, byte value)
static void	setMemory(long address, long bytes, byte value)
static java.util.Random	threadLocalRandom() Return a Random which is not-threadsafe and so can only be used from the same thread.
static void	throwException(java.lang.Throwable t) Raises an exception bypassing compiler checks for checked exceptions.
static java.io.File	tmpdir() Returns the temporary directory.
static boolean	useDirectBufferNoCleaner()

从类继承的方法 java.lang.Object

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

字段详细资料

BIG_ENDIAN_NATIVE_ORDER

public static final boolean BIG_ENDIAN_NATIVE_ORDER

方法详细资料

hasDirectBufferNoCleanerConstructor

public static boolean hasDirectBufferNoCleanerConstructor()

allocateUninitializedArray

public static byte[] allocateUninitializedArray(int size)

isAndroid

public static boolean isAndroid()

Returns true if and only if the current platform is Android

isWindows

public static boolean isWindows()

Return true if the JVM is running on Windows

isOsx

public static boolean isOsx()

Return true if the JVM is running on OSX / MacOS

maybeSuperUser

public static boolean maybeSuperUser()

Return true if the current user may be a super-user. Be aware that this is just an hint and so it may return false-positives.

javaVersion

public static int javaVersion()

Return the version of Java under which this library is used.

canEnableTcpNoDelayByDefault

public static boolean canEnableTcpNoDelayByDefault()

Returns true if and only if it is fine to enable TCP_NODELAY socket option by default.

hasUnsafe

public static boolean hasUnsafe()

Return true if sun.misc.Unsafe was found on the classpath and can be used for accelerated direct memory access.

getUnsafeUnavailabilityCause

public static java.lang.Throwable getUnsafeUnavailabilityCause()

Return the reason (if any) why sun.misc.Unsafe was not available.

isUnaligned

public static boolean isUnaligned()

true if and only if the platform supports unaligned access.

另请参阅:

Wikipedia on segfault

directBufferPreferred

public static boolean directBufferPreferred()

Returns true if the platform has reliable low-level direct buffer access API and a user has not specified -Dio.netty.noPreferDirect option.

maxDirectMemory

public static long maxDirectMemory()

Returns the maximum memory reserved for direct buffer allocation.

tmpdir

public static java.io.File tmpdir()

Returns the temporary directory.

bitMode

public static int bitMode()

Returns the bit mode of the current VM (usually 32 or 64.)

addressSize

public static int addressSize()

Return the address size of the OS. 4 (for 32 bits systems ) and 8 (for 64 bits systems).

allocateMemory

public static long allocateMemory(long size)

freeMemory

public static void freeMemory(long address)

throwException

public static void throwException(java.lang.Throwable t)

Raises an exception bypassing compiler checks for checked exceptions.

newConcurrentHashMap

public static <K,V> java.util.concurrent.ConcurrentMap<K,V> newConcurrentHashMap()

Creates a new fastest ConcurrentMap implementation for the current platform.

newLongCounter

public static LongCounter newLongCounter()

Creates a new fastest LongCounter implementation for the current platform.

newConcurrentHashMap

public static <K,V> java.util.concurrent.ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity)

Creates a new fastest ConcurrentMap implementation for the current platform.

newConcurrentHashMap

public static <K,V> java.util.concurrent.ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity,
                                                                 float loadFactor)

Creates a new fastest ConcurrentMap implementation for the current platform.

newConcurrentHashMap

public static <K,V> java.util.concurrent.ConcurrentMap<K,V> newConcurrentHashMap(int initialCapacity,
                                                                 float loadFactor,
                                                                 int concurrencyLevel)

Creates a new fastest ConcurrentMap implementation for the current platform.

newConcurrentHashMap

public static <K,V> java.util.concurrent.ConcurrentMap<K,V> newConcurrentHashMap(java.util.Map<? extends K,? extends V> map)

Creates a new fastest ConcurrentMap implementation for the current platform.

freeDirectBuffer

public static void freeDirectBuffer(java.nio.ByteBuffer buffer)

Try to deallocate the specified direct ByteBuffer. Please note this method does nothing if the current platform does not support this operation or the specified buffer is not a direct buffer.

directBufferAddress

public static long directBufferAddress(java.nio.ByteBuffer buffer)

directBuffer

public static java.nio.ByteBuffer directBuffer(long memoryAddress,
                               int size)

getInt

public static int getInt(java.lang.Object object,
         long fieldOffset)

getByte

public static byte getByte(long address)

getShort

public static short getShort(long address)

getInt

public static int getInt(long address)

getLong

public static long getLong(long address)

getByte

public static byte getByte(byte[] data,
           int index)

getShort

public static short getShort(byte[] data,
             int index)

getInt

public static int getInt(byte[] data,
         int index)

getLong

public static long getLong(byte[] data,
           int index)

putByte

public static void putByte(long address,
           byte value)

putShort

public static void putShort(long address,
            short value)

putInt

public static void putInt(long address,
          int value)

putLong

public static void putLong(long address,
           long value)

putByte

public static void putByte(byte[] data,
           int index,
           byte value)

putShort

public static void putShort(byte[] data,
            int index,
            short value)

putInt

public static void putInt(byte[] data,
          int index,
          int value)

putLong

public static void putLong(byte[] data,
           int index,
           long value)

copyMemory

public static void copyMemory(long srcAddr,
              long dstAddr,
              long length)

copyMemory

public static void copyMemory(byte[] src,
              int srcIndex,
              long dstAddr,
              long length)

copyMemory

public static void copyMemory(long srcAddr,
              byte[] dst,
              int dstIndex,
              long length)

setMemory

public static void setMemory(byte[] dst,
             int dstIndex,
             long bytes,
             byte value)

setMemory

public static void setMemory(long address,
             long bytes,
             byte value)

allocateDirectNoCleaner

public static java.nio.ByteBuffer allocateDirectNoCleaner(int capacity)

Allocate a new ByteBuffer with the given capacity. ByteBuffers allocated with this method MUST be deallocated via freeDirectNoCleaner(ByteBuffer).

reallocateDirectNoCleaner

public static java.nio.ByteBuffer reallocateDirectNoCleaner(java.nio.ByteBuffer buffer,
                                            int capacity)

Reallocate a new ByteBuffer with the given capacity. ByteBuffers reallocated with this method MUST be deallocated via freeDirectNoCleaner(ByteBuffer).

freeDirectNoCleaner

public static void freeDirectNoCleaner(java.nio.ByteBuffer buffer)

This method MUST only be called for ByteBuffers that were allocated via allocateDirectNoCleaner(int).

useDirectBufferNoCleaner

public static boolean useDirectBufferNoCleaner()

isZero

public static boolean isZero(byte[] bytes,
             int startPos,
             int length)

Determine if a subsection of an array is zero.

参数:

bytes - The byte array.

startPos - The starting index (inclusive) in bytes.

length - The amount of bytes to check for zero.

返回:

false if bytes[startPos:startsPos+length) contains a value other than zero.

newMpscQueue

public static <T> java.util.Queue<T> newMpscQueue()

Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).

返回:

A MPSC queue which may be unbounded.

newMpscQueue

public static <T> java.util.Queue<T> newMpscQueue(int maxCapacity)

Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!).

newSpscQueue

public static <T> java.util.Queue<T> newSpscQueue()

Create a new Queue which is safe to use for single producer (one thread!) and a single consumer (one thread!).

newFixedMpscQueue

public static <T> java.util.Queue<T> newFixedMpscQueue(int capacity)

Create a new Queue which is safe to use for multiple producers (different threads) and a single consumer (one thread!) with the given fixes capacity.

getClassLoader

public static java.lang.ClassLoader getClassLoader(java.lang.Class<?> clazz)

Return the ClassLoader for the given Class.

getContextClassLoader

public static java.lang.ClassLoader getContextClassLoader()

Return the context ClassLoader for the current Thread.

getSystemClassLoader

public static java.lang.ClassLoader getSystemClassLoader()

Return the system ClassLoader.

newConcurrentDeque

public static <C> java.util.Deque<C> newConcurrentDeque()

Returns a new concurrent Deque.

threadLocalRandom

public static java.util.Random threadLocalRandom()

Return a Random which is not-threadsafe and so can only be used from the same thread.

normalizedArch

public static java.lang.String normalizedArch()

normalizedOs

public static java.lang.String normalizedOs()