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import jas.*;
import java.io.*;
//
// This is program that makes calls into the jas package
// to generate a class that prints a string afew times.
//
class hworld implements RuntimeConstants
{
public static void main(String argv[])
throws jasError, IOException
{
// class hierarchy
ClassEnv nclass = new ClassEnv();
nclass.setClass(new ClassCP("out"));
nclass.setSuperClass(new ClassCP("java/lang/Object"));
nclass.setClassAccess((short)ACC_PUBLIC);
// Initialization code
CodeAttr init = new CodeAttr();
init.addInsn(new Insn(opc_aload_0));
init.addInsn(new Insn(opc_invokenonvirtual,
new MethodCP("java/lang/Object", "<init>", "()V")));
init.addInsn(new Insn(opc_return));
// Actual code to print string
CodeAttr doit = new CodeAttr();
// store refs in local variables
doit.addInsn(new Insn(opc_getstatic,
new FieldCP("java/lang/System",
"out",
"Ljava/io/PrintStream;")));
doit.addInsn(new Insn(opc_astore_1));
doit.addInsn(new Insn(opc_ldc,
new StringCP("Hello World")));
doit.addInsn(new Insn(opc_astore_2));
// Loop index in var reg 3
doit.addInsn(new Insn(opc_bipush, 5));
doit.addInsn(new Insn(opc_istore_3));
// Start the loop
Label loop = new Label("loop");
doit.addInsn(loop);
doit.addInsn(new Insn(opc_aload_1));
doit.addInsn(new Insn(opc_aload_2));
doit.addInsn(new Insn(opc_invokevirtual,
new MethodCP("java/io/PrintStream",
"println",
"(Ljava/lang/String;)V")));
doit.addInsn(new IincInsn(3, -1));
doit.addInsn(new Insn(opc_iload_3));
doit.addInsn(new Insn(opc_ifne, loop));
doit.addInsn(new Insn(opc_return));
// set the right sizes for code
doit.setStackSize((short)3); doit.setVarSize((short)4);
// Add the init code to the class.
nclass.addMethod((short)ACC_PUBLIC, "<init>", "()V", init, null);
// Add the printing code
nclass.addMethod((short)(ACC_PUBLIC|ACC_STATIC), "main",
"([Ljava/lang/String;)V", doit, null);
// write it all out
nclass.write(new DataOutputStream
(new FileOutputStream("out.class")));
}
}
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