@SuppressWarnings("UnusedDeclaration")
public static CallSite bootstrapInit(MethodHandles.Lookup caller, String name, MethodType type) {
RoboCallSite site = new RoboCallSite(type, caller.lookupClass());
bindInitCallSite(site);
return site;
}
@SuppressWarnings("UnusedDeclaration")
public static CallSite bootstrapStatic(
MethodHandles.Lookup caller, String name, MethodType type, MethodHandle original)
throws IllegalAccessException {
MethodCallSite site = new MethodCallSite(type, caller.lookupClass(), name, original, STATIC);
bindCallSite(site);
return site;
}
public static CallSite bootstrap(
MethodHandles.Lookup caller, String name, MethodType type, String targetType)
throws NoSuchMethodException, IllegalAccessException, ClassNotFoundException {
// lookup the target type within the ClassLoader of the
// calling class, otherwise this bootstrap class may not
// have visibility (if loaded through AnonymousClassLoader, etc)
Class<?> targetClass = Class.forName(targetType, true, caller.lookupClass().getClassLoader());
InterfaceCallSite ics = new InterfaceCallSite(targetClass, name, type);
// set the interface class, method name, and method type
// as the first arguments of the handle, then have
// it collect whatever arguments are sent at runtime
// into a trailing Object[]
ics.rootHandle =
MethodHandles.insertArguments(callHandle, 0, ics)
.asVarargsCollector(Object[].class)
.asType(type);
ics.setTarget(ics.rootHandle);
return ics;
}
public static void main(String[] arg) throws Throwable {
MethodHandles.Lookup lookup = MethodHandles.lookup();
Class thisClass = lookup.lookupClass(); // (who am I?)
MethodType methodType;
MethodHandle methodHandle;
Employee employee = new Employee();
String name;
Field fieldName = null;
for (Field field : Employee.class.getDeclaredFields()) {
if (field.getName().equals("name")) {
fieldName = field;
fieldName.setAccessible(true);
break;
}
}
// Lookup invoke dynamic
methodType = MethodType.methodType(String.class);
methodHandle = lookup.findVirtual(Employee.class, "getName", methodType);
name = (String) methodHandle.invokeExact(new Employee());
System.out.println("invoke dynamic " + name);
// Lookup reflection
Method method = Employee.class.getMethod("getName", new Class<?>[] {});
name = (String) method.invoke(new Employee());
System.out.println("reflection " + name);
// Lookup Handle Field Direct
MethodHandle methodHandleFieldDirect = lookup.unreflectGetter(fieldName);
name = (String) methodHandleFieldDirect.invokeExact(new Employee());
System.out.println("method handle for field direct " + name);
long start = 0;
long end = 0;
long times = 10_000;
long regularTime;
long invokeDynamicTime;
long reflectionTime;
long count = 0;
long invokeDynamicTimeUsingField;
long fieldDirect;
// warm up
for (int index = 0; index < times; index++) {
employee.getName();
name = (String) methodHandle.invokeExact(employee);
name = (String) method.invoke(employee);
name = (String) methodHandleFieldDirect.invokeExact(employee);
}
// regular method call time
start = System.nanoTime();
for (int index = 0; index < times; index++) {
name = employee.getName();
count += name.hashCode();
}
count = 0;
end = System.nanoTime();
regularTime = end - start;
System.out.printf("regular method call time = %d\n", regularTime / times);
// invoke dynamic method call time
start = System.nanoTime();
for (int index = 0; index < times; index++) {
name = (String) methodHandle.invokeExact(employee);
count += name.hashCode();
}
count = 0;
end = System.nanoTime();
invokeDynamicTime = end - start;
System.out.printf("invoke dynamic method call time = %d\n", invokeDynamicTime / times);
// reflection method call time
start = System.nanoTime();
for (int index = 0; index < times; index++) {
name = (String) method.invoke(employee);
count += name.hashCode();
}
count = 0;
end = System.nanoTime();
reflectionTime = end - start;
System.out.printf("reflection method call time = %d\n", reflectionTime / times);
//
start = System.nanoTime();
for (int index = 0; index < times; index++) {
name = (String) methodHandleFieldDirect.invokeExact(employee);
count += name.hashCode();
}
count = 0;
end = System.nanoTime();
invokeDynamicTimeUsingField = end - start;
System.out.printf(
"field method invoke dynamic call time = %d\n", invokeDynamicTimeUsingField / times);
//
start = System.nanoTime();
for (int index = 0; index < times; index++) {
name = (String) fieldName.get(employee);
count += name.hashCode();
}
count = 0;
end = System.nanoTime();
fieldDirect = end - start;
System.out.printf("field method reflection call time = %d\n", fieldDirect / times);
}