org.geotools.util

Class NIOUtilities

Object

NIOUtilities

public final class NIOUtilities
extends Object

Utility class for managing memory mapped buffers.

Since:

2.0

Author:

Andrea Aimes

Method Summary

Modifier and Type	Method and Description
static ByteBuffer	allocate(int size) Allocates and returns a ByteBuffer.
static boolean	clean(ByteBuffer buffer) Really closes a MappedByteBuffer without the need to wait for garbage collection.
static boolean	clean(ByteBuffer buffer, boolean memoryMapped) Depending on the type of buffer different cleanup action will be taken: if the buffer is memory mapped (as per the specified parameter) the effect is the same as clean(ByteBuffer) if the buffer is not memory mapped it will be returned to the buffer cache
static boolean	isDirectBuffersEnabled() Wheter direct buffers are used, or not (defaults to true)
static boolean	returnToCache(ByteBuffer buffer)
static void	setDirectBuffersEnabled(boolean directBuffersEnabled) If the flag is true allocate(int) will allocate a direct buffer,, otherwise heap buffers will be used.
static void	setMaxCacheSize(int maxCacheSize) Sets the maximum byte buffer cache size, in bytes (set to 0 to only use soft references in the case, a positive value will make the cache use hard references up to the max cache size)

Methods inherited from class Object

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

Method Detail

isDirectBuffersEnabled

public static boolean isDirectBuffersEnabled()

Wheter direct buffers are used, or not (defaults to true)

Returns:

setDirectBuffersEnabled

public static void setDirectBuffersEnabled(boolean directBuffersEnabled)

If the flag is true allocate(int) will allocate a direct buffer,, otherwise heap buffers will be used. Direct buffers are normally faster, but their cleanup is platform dependent and not guaranteed, under high load and in combination with some garbage collectors that might result in a JVM crash (failure to perform native memory allocation)

Parameters:

directBuffersEnabled -

setMaxCacheSize

public static void setMaxCacheSize(int maxCacheSize)

Sets the maximum byte buffer cache size, in bytes (set to 0 to only use soft references in the case, a positive value will make the cache use hard references up to the max cache size)

Parameters:

maxCacheSize -

allocate

public static ByteBuffer allocate(int size)

Allocates and returns a ByteBuffer. The buffer capacity will generally be greater than of two that can contain the specified limit, the buffer limit will be set at the specified value. The buffers are pooled, so remember to call #clean(ByteBuffer, false) to return the buffer to the pool.

Parameters:

limit -

Returns:

clean

public static boolean clean(ByteBuffer buffer,
                            boolean memoryMapped)

Depending on the type of buffer different cleanup action will be taken:

• if the buffer is memory mapped (as per the specified parameter) the effect is the same as clean(ByteBuffer)
• if the buffer is not memory mapped it will be returned to the buffer cache

Parameters:

buffer -

Returns:

clean

public static boolean clean(ByteBuffer buffer)

Really closes a MappedByteBuffer without the need to wait for garbage collection. Any problems with closing a buffer on Windows (the problem child in this case) will be logged as SEVERE to the logger of the package name. To force logging of errors, set the System property "org.geotools.io.debugBuffer" to "true".

Starting from Java 9 the underlying Java runtime issue got fixed, so the method returns immediately in that case, without forcing any cleaning by reflection on a non exposed API

Parameters:

buffer - The buffer to close.

Returns:

true if the operation was successful, false otherwise.

See Also:

MappedByteBuffer

returnToCache

public static boolean returnToCache(ByteBuffer buffer)