Dynamic FFM

Java 21 based JEP 454 Foreign Function and Memory API - Alternative to JNI and JNA

To see how to use it, check Test.java.

Important!!!

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Build

1. Clone repository to local drive
2. Use maven build clean install

Quickstart

Define Java Interface with methods representing foreign functions. All parameters and return types are of a type MemorySegment (aka pointer) except for primitive types.

Latest change support primitive type arrays also.

Example - C/C++ pseudo code

void function process(int percentage)
*byte[] compress(int level, *byte[] data, *process callback) {
 ... do compression and return pointer to compressed data ...
}

Example - Java mapping options

@External(name="compression.dll")
interface ForeignCompressor (

  // Option 1 - with more low level control
  MemorySegment compress(int level, MemorySegment data, MemorySegment callback)

  // Option 2 - with automatic data conversion; callback must be bind to an instance
  byte[] compress(int level, byte[] data, MethodHandle callback)

  // Option 3 - with automatic data conversion
  byte[] compress(int level, byte[] data, @Callback(name="process") ICallback callback)

)

interface ICallback {

    @Callback(name="process")
    void callback(int percentage)
}

Finally, create a callable instance.

final ForeignCompressor instance = ExternalFactory.create(ForeignCompressor.class);

byte[] compressed = instance.compress(6, "Quick brown fox jumps over the lazy dog".getBytes(), null);

NOTE: @Callback can be named and unnamed. When interface contains only a single Callback, named callbacks are not required. When iterface contains multiple calllback methods, use named callback to map porper method to foreign function callback argument.

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