Click or drag to resize

IJVMWrapperDirectNewDirectBuffer(MemoryStream, Boolean, EventHandlerMemoryStream, Int32) Method

Creates a new https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html in the JVM by performing an internal copy of the content of stream.

Namespace: MASES.JCOBridge.C2JBridge.JVMInterop
Assembly: C2JBridge (in C2JBridge.dll) Version: 2.6.9.260611-9a148513a79c26cdd7f1dde468f4f9e06ef3bc7e
Syntax
Copy
JCOBridgeDirectBuffer<byte> NewDirectBuffer(
	MemoryStream stream,
	bool useMemoryControlBlock = false,
	EventHandler<MemoryStream> disposeEvent = null,
	int timeToLive = -1
)

Parameters

stream  MemoryStream
The non-disposed MemoryStream whose content will be copied into an internal buffer shared with the JVM via a https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html.
useMemoryControlBlock  Boolean  (Optional)
NO MORE USED STARTING FROM VERSION 2.6.9 - Appends to the end of the stream a memory block used to control and arbitrate memory between CLR and JVM.
disposeEvent  EventHandlerMemoryStream  (Optional)
An optional EventHandlerTEventArgs used to be informed when the internal copy derived from stream is no longer needed by the JVM, allowing the caller to dispose stream at the right time. If , the underlying system will automatically dispose the MemoryStream.
timeToLive  Int32  (Optional)
The time to live, expressed in milliseconds, the internal copy shall remain available; if the time to live expires the memory is retired leaving potentially the JVM under the possibility of an access violation.

Return Value

JCOBridgeDirectBufferByte
A new instance of JCOBridgeDirectBufferT holding an internal copy of stream shared with the https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html.
Exceptions
ExceptionCondition
NotSupportedExceptionThrown when the JVM is unable to generate a https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html instance.
Remarks
Starting from version 2.6.9, the content of stream is no longer pinned in memory but copied into an internal buffer managed by the subsystem. Prior to version 2.6.9, the memory had to be pinned for the entire duration of the JVM usage to prevent access violations; the introduction of the internal copy removes this constraint, allowing stream to have an arbitrary lifetime without impacting the correctness of the operation. The internal copy remains available until the JVM reference of the newly created https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html is garbage collected. Under heavy pressure the memory footprint can raise up and generate an OutOfMemoryException, use the functionality with caution or take into account the timeToLive option which can help to recover the memory in advance before the Garbage Collector of the JVM retires the https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html. If the user of JCOBridgeDirectBufferT is pretty sure that the internal copy is no longer needed from the JVM, e.g. the invoked method does not queue the https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html and its lifetime ends when the method returns, invoke Dispose to immediately release unmanaged resources and free the memory.

High-rate scenarios: for activities with a high invocation rate, consider using RentT(Int64) to obtain a pooled JCOBridgeSharedBufferStreamT, fill it using Stream-based APIs, and then pass the populated instance to NewDirectBufferT(JCOBridgeSharedBufferStreamT). That overload automatically manages the lifecycle of the JCOBridgeSharedBufferStreamT by returning it to the pool once the JVM Garbage Collector retires the associated https://docs.oracle.com/javase/8/docs/api/java/nio/ByteBuffer.html, avoiding repeated allocation and copy overhead.

See Also