How can I use Reflection (Mirrors) to access the method names in a Dart Class? - dart

Question

I need to "fetch" the methods in a Dart Class.
How can I do this?
And I want to be able to call the methods.
May I see an example?

Answer 1

Here's an easy copy-pasteable code sample:
import 'dart:mirrors';
import 'dart:io';
main() {
var im = reflect(new File('test')); // Retrieve the InstanceMirror of some class instance.
im.type.methods.values.forEach((MethodMirror method) => print(method.simpleName));
}
Output is:
existsSync
_delete
exists
directory
_getDecodedLines
readAsTextSync
readAsBytesSync
readAsLinesSync
_directory
throwIfError
lastModifiedSync
readAsLines
open
_ensureFileService
deleteSync
delete
_exists
length
openInputStream
create
_create
readAsText
_openStdioSync
openOutputStream
_fullPath
_lastModified
fullPathSync
readAsBytes
lastModified
_openStdio
_open
openSync
lengthSync
directorySync
fullPath
createSync
_lengthFromName

Answer 2

Here is a basic example:
(Note: You will want to have a (very) up to date version of the SDK for this, this was done in Dart Editor version 0.2.1_r14167, Dart SDK version 0.2.1.2_r14167 Nov 2, 2012)
My most sincere Thanks to Gilad of the Google Dart Team for providing this example!
#import('dart:mirrors');
class MyClass {
String _test;
String get test => _test;
set test(String paramVal) => _test = paramVal;
void my_method() {
}
void print_test(){
print("test string is: ${_test}");
}
MyClass(String test) {
_test = test;
}
}
main() {
MyClass myClass = new MyClass("Make my day, PUNK.");
myClass.print_test();
//ClassMirror myClassMirror = reflect(myClass).type;
InstanceMirror myClassInstanceMirror = reflect(myClass);
ClassMirror MyClassMirror = myClassInstanceMirror.type;
Map<String, MethodMirror> map = MyClassMirror.methods;
print("map = ${map}");
map.values.forEach( (MethodMirror mm){
myClassInstanceMirror.invoke(mm.simpleName,[]);
});
}

Answer 3

Concerning Reflection I have just written a couple of "Helper Functions" for fetching a LIST of the method names (not a Map) and invoking the method... all I can say for sure is that it works right now. There are likely technical reasons for not doing it this way - but in my case this does not run in a complex environment. However, I do think they nicely mask over a lot of details that not everybody is going to want to deal with.
Here's a functioning demonstration with and without the Helper functions:
#import('dart:mirrors');
class MyClass {
String _test;
String get test => _test;
set test(String paramVal) => _test = paramVal;
void my_method1(){print("in method1");}
void my_method2(){print("in method2");}
void print_test(){
print("test string is: ${_test}");
}
MyClass(String test) {
_test = test;
}
}
//Helper Methods
InstanceMirror hMr;
List REFLECT_methods(Object myClass) {hMr=reflect(myClass);return(hMr.type.methods.values);}
REFLECT_invoke(MethodMirror mm){hMr.invoke(mm.simpleName, []);}
main() {
MyClass myClass = new MyClass("Make my day, PUNK.");
print("\n=======Using Raw Reflection================");
InstanceMirror myClassInstanceMirror = reflect(myClass);
ClassMirror MyClassMirror = myClassInstanceMirror.type;
Map<String, MethodMirror> map1 = MyClassMirror.methods;
map1.values.forEach( (MethodMirror mm){
myClassInstanceMirror.invoke(mm.simpleName,[]);
});
print("\n==========Using Helper functions=============");
List list2 = REFLECT_methods(myClass);
list2.forEach((method){
REFLECT_invoke(method);
});
}