Examples with VarHandle java.lang.invoke.VarHandle used on opensource projects

Example 1 with VarHandle

use of java.lang.invoke.VarHandle in project tutorials by eugenp.

the class VariableHandlesTest method givenVarHandle_whenSetIsInvoked_ThenValueOfVariableIsChanged.

@Test
public void givenVarHandle_whenSetIsInvoked_ThenValueOfVariableIsChanged() throws NoSuchFieldException, IllegalAccessException {
    VarHandle publicIntHandle = MethodHandles.lookup().in(VariableHandlesTest.class).findVarHandle(VariableHandlesTest.class, "variableToSet", int.class);
    publicIntHandle.set(this, 15);
    assertThat((int) publicIntHandle.get(this) == 15);
}

Example 2 with VarHandle

use of java.lang.invoke.VarHandle in project tutorials by eugenp.

the class VariableHandlesTest method whenVariableHandleForPrivateVariableIsCreated_ThenItIsInitializedProperly.

@Test
public void whenVariableHandleForPrivateVariableIsCreated_ThenItIsInitializedProperly() throws NoSuchFieldException, IllegalAccessException {
    VarHandle privateIntHandle = MethodHandles.privateLookupIn(VariableHandlesTest.class, MethodHandles.lookup()).findVarHandle(VariableHandlesTest.class, "privateTestVariable", int.class);
    assertThat(privateIntHandle.coordinateTypes().size() == 1);
    assertThat(privateIntHandle.coordinateTypes().get(0) == VariableHandlesTest.class);
}

Example 3 with VarHandle

use of java.lang.invoke.VarHandle in project tutorials by eugenp.

the class VariableHandlesTest method whenVariableHandleForArrayVariableIsCreated_ThenItIsInitializedProperly.

@Test
public void whenVariableHandleForArrayVariableIsCreated_ThenItIsInitializedProperly() throws NoSuchFieldException, IllegalAccessException {
    VarHandle arrayVarHandle = MethodHandles.arrayElementVarHandle(int[].class);
    assertThat(arrayVarHandle.coordinateTypes().size() == 2);
    assertThat(arrayVarHandle.coordinateTypes().get(0) == int[].class);
}

Example 4 with VarHandle

use of java.lang.invoke.VarHandle in project tutorials by eugenp.

the class VariableHandlesTest method givenVarHandle_whenGetIsInvoked_ThenValueOfVariableIsReturned.

@Test
public void givenVarHandle_whenGetIsInvoked_ThenValueOfVariableIsReturned() throws NoSuchFieldException, IllegalAccessException {
    VarHandle publicIntHandle = MethodHandles.lookup().in(VariableHandlesTest.class).findVarHandle(VariableHandlesTest.class, "publicTestVariable", int.class);
    assertThat((int) publicIntHandle.get(this) == 1);
}

Example 5 with VarHandle

use of java.lang.invoke.VarHandle in project openj9 by eclipse.

the class StructTests method test_addFloatFromPointerAndFloatsFromStruct_returnFloatPointer.

@Test
public void test_addFloatFromPointerAndFloatsFromStruct_returnFloatPointer() throws Throwable {
    GroupLayout structLayout = MemoryLayout.ofStruct(C_FLOAT.withName("elem1"), C_FLOAT.withName("elem2"));
    VarHandle floatHandle1 = structLayout.varHandle(float.class, PathElement.groupElement("elem1"));
    VarHandle floatHandle2 = structLayout.varHandle(float.class, PathElement.groupElement("elem2"));
    MethodType mt = MethodType.methodType(MemoryAddress.class, MemoryAddress.class, MemorySegment.class);
    FunctionDescriptor fd = FunctionDescriptor.of(C_POINTER, C_POINTER, structLayout);
    Symbol functionSymbol = nativeLib.lookup("addFloatFromPointerAndFloatsFromStruct_returnFloatPointer").get();
    MethodHandle mh = clinker.downcallHandle(functionSymbol, mt, fd);
    MemorySegment floatSegmt = MemorySegment.allocateNative(C_FLOAT);
    MemoryAccess.setFloat(floatSegmt, 12.12F);
    MemorySegment structSegmt = MemorySegment.allocateNative(structLayout);
    floatHandle1.set(structSegmt, 18.23F);
    floatHandle2.set(structSegmt, 19.34F);
    MemoryAddress resultAddr = (MemoryAddress) mh.invokeExact(floatSegmt.address(), structSegmt);
    MemorySegment resultSegmt = resultAddr.asSegmentRestricted(C_FLOAT.byteSize());
    VarHandle floatHandle = MemoryHandles.varHandle(float.class, ByteOrder.nativeOrder());
    float result = (float) floatHandle.get(resultSegmt, 0);
    Assert.assertEquals(result, 49.69F, 0.01F);
    Assert.assertEquals(resultSegmt.address().toRawLongValue(), floatSegmt.address().toRawLongValue());
    floatSegmt.close();
    structSegmt.close();
    resultSegmt.close();
}