Main.asm

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// Simple sample to demonstrate openjdk asmtools assembler with
// nashorn dynalink linker in a invokedynamic instruction.
//
// To assemble this file, use the following command:
//
//    java -cp <asmtools.jar> org.openjdk.asmtools.Main jasm Main.asm
//
// See also: https://wiki.openjdk.java.net/display/CodeTools/asmtools
//
// NOTE: Uses nashorn internals and so *may* break with later nashorn!

super public class Main
	version 52:0
{


public Method "<init>":"()V"
	stack 1 locals 1
{
		aload_0;
		invokespecial	Method java/lang/Object."<init>":"()V";
		return;
}

public static Method main:"([Ljava/lang/String;)V"
	stack 2 locals 2
{
                // List l = new ArrayList();
		new	class java/util/ArrayList;
		dup;
		invokespecial	Method java/util/ArrayList."<init>":"()V";
		astore_1;
		aload_1;

                // l.add("hello");
		ldc	String "hello";
		invokeinterface	InterfaceMethod java/util/List.add:"(Ljava/lang/Object;)Z",  2;
		pop;

                // l.add("world");
		aload_1;
		ldc	String "world";
		invokeinterface	InterfaceMethod java/util/List.add:"(Ljava/lang/Object;)Z",  2;
		pop;

                // printLength(l);
		aload_1;
		invokestatic	Method printLength:"(Ljava/lang/Object;)V";

                // printLength(args); // args is argument of main method
		aload_0;
		invokestatic	Method printLength:"(Ljava/lang/Object;)V";
		return;
}

private static Method printLength:"(Ljava/lang/Object;)V"
	stack 2 locals 1
{
		getstatic	Field java/lang/System.out:"Ljava/io/PrintStream;";
		aload_0;

                // Using nashorn embedded dynalink linker with the following invokedynamic
                // 'length' property on a bean - arrays, lists supported

                invokedynamic   InvokeDynamic REF_invokeStatic:jdk/nashorn/internal/runtime/linker/Bootstrap.bootstrap:"(Ljava/lang/invoke/MethodHandles$Lookup;Ljava/lang/String;Ljava/lang/invoke/MethodType;I)Ljava/lang/invoke/CallSite;":"dyn:getProp|getElem|getMethod:length":"(Ljava/lang/Object;)Ljava/lang/Object;" int 0;

                // print 'length' value
		invokevirtual	Method java/io/PrintStream.println:"(Ljava/lang/Object;)V";
		return;
}

} // end Class Main