public class ASMifierClassVisitor extends ASMifierAbstractVisitor implements ClassVisitor
ClassVisitor that prints the ASM code that generates the classes it
visits. This class visitor can be used to quickly write ASM code to generate
some given bytecode: ASMifierClassVisitor visit this compiled class (see the
main method);
import org.objectweb.asm.*;
public class HelloDump implements Opcodes {
public static byte[] dump() throws Exception {
ClassWriter cw = new ClassWriter(0);
FieldVisitor fv;
MethodVisitor mv;
AnnotationVisitor av0;
cw.visit(49,
ACC_PUBLIC + ACC_SUPER,
"Hello",
null,
"java/lang/Object",
null);
cw.visitSource("Hello.java", null);
{
mv = cw.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
mv.visitVarInsn(ALOAD, 0);
mv.visitMethodInsn(INVOKESPECIAL,
"java/lang/Object",
"<init>",
"()V");
mv.visitInsn(RETURN);
mv.visitMaxs(1, 1);
mv.visitEnd();
}
{
mv = cw.visitMethod(ACC_PUBLIC + ACC_STATIC,
"main",
"([Ljava/lang/String;)V",
null,
null);
mv.visitFieldInsn(GETSTATIC,
"java/lang/System",
"out",
"Ljava/io/PrintStream;");
mv.visitLdcInsn("hello");
mv.visitMethodInsn(INVOKEVIRTUAL,
"java/io/PrintStream",
"println",
"(Ljava/lang/String;)V");
mv.visitInsn(RETURN);
mv.visitMaxs(2, 1);
mv.visitEnd();
}
cw.visitEnd();
return cw.toByteArray();
}
}
where Hello is defined by:
public class Hello {
public static void main(String[] args) {
System.out.println("hello");
}
}
| Modifier and Type | Field and Description |
|---|---|
protected PrintWriter |
pw
The print writer to be used to print the class.
|
namebuf, OPCODES, text, TYPES| Constructor and Description |
|---|
ASMifierClassVisitor(PrintWriter pw)
Constructs a new
ASMifierClassVisitor object. |
| Modifier and Type | Method and Description |
|---|---|
protected ASMifierMethodVisitor |
createASMifierMethodVisitor() |
static void |
main(String[] args)
Prints the ASM source code to generate the given class to the standard
output.
|
void |
visit(int version,
int access,
String name,
String signature,
String superName,
String[] interfaces)
Visits the header of the class.
|
AnnotationVisitor |
visitAnnotation(String desc,
boolean visible)
Prints the ASM code that generates the given annotation.
|
void |
visitEnd()
Prints the ASM code to end the visit.
|
FieldVisitor |
visitField(int access,
String name,
String desc,
String signature,
Object value)
Visits a field of the class.
|
void |
visitInnerClass(String name,
String outerName,
String innerName,
int access)
Visits information about an inner class.
|
MethodVisitor |
visitMethod(int access,
String name,
String desc,
String signature,
String[] exceptions)
Visits a method of the class.
|
void |
visitOuterClass(String owner,
String name,
String desc)
Visits the enclosing class of the class.
|
void |
visitSource(String file,
String debug)
Visits the source of the class.
|
visitAttributeappendString, getDefaultAttributes, getText, printclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitvisitAttributeprotected final PrintWriter pw
public ASMifierClassVisitor(PrintWriter pw)
ASMifierClassVisitor object.pw - the print writer to be used to print the class.public static void main(String[] args) throws Exception
Usage: ASMifierClassVisitor [-debug] <fully qualified class name or class file name>
args - the command line arguments.Exception - if the class cannot be found, or if an IO exception
occurs.public void visit(int version,
int access,
String name,
String signature,
String superName,
String[] interfaces)
ClassVisitorvisit in interface ClassVisitorversion - the class version.access - the class's access flags (see Opcodes). This
parameter also indicates if the class is deprecated.name - the internal name of the class (see
getInternalName).signature - the signature of this class. May be null if
the class is not a generic one, and does not extend or implement
generic classes or interfaces.superName - the internal of name of the super class (see
getInternalName). For interfaces,
the super class is Object. May be null, but
only for the Object class.interfaces - the internal names of the class's interfaces (see
getInternalName). May be
null.public void visitSource(String file, String debug)
ClassVisitorvisitSource in interface ClassVisitorfile - the name of the source file from which the class was
compiled. May be null.debug - additional debug information to compute the correspondance
between source and compiled elements of the class. May be
null.public void visitOuterClass(String owner, String name, String desc)
ClassVisitorvisitOuterClass in interface ClassVisitorowner - internal name of the enclosing class of the class.name - the name of the method that contains the class, or
null if the class is not enclosed in a method of its
enclosing class.desc - the descriptor of the method that contains the class, or
null if the class is not enclosed in a method of its
enclosing class.public void visitInnerClass(String name, String outerName, String innerName, int access)
ClassVisitorvisitInnerClass in interface ClassVisitorname - the internal name of an inner class (see
getInternalName).outerName - the internal name of the class to which the inner class
belongs (see getInternalName). May
be null for not member classes.innerName - the (simple) name of the inner class inside its
enclosing class. May be null for anonymous inner
classes.access - the access flags of the inner class as originally declared
in the enclosing class.public FieldVisitor visitField(int access, String name, String desc, String signature, Object value)
ClassVisitorvisitField in interface ClassVisitoraccess - the field's access flags (see Opcodes). This
parameter also indicates if the field is synthetic and/or
deprecated.name - the field's name.desc - the field's descriptor (see Type).signature - the field's signature. May be null if the
field's type does not use generic types.value - the field's initial value. This parameter, which may be
null if the field does not have an initial value, must
be an Integer, a Float, a Long, a
Double or a String (for int,
float, long or String fields
respectively). This parameter is only used for static fields.
Its value is ignored for non static fields, which must be
initialized through bytecode instructions in constructors or
methods.public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions)
ClassVisitorMethodVisitor instance (or null) each time it is
called, i.e., it should not return a previously returned visitor.visitMethod in interface ClassVisitoraccess - the method's access flags (see Opcodes). This
parameter also indicates if the method is synthetic and/or
deprecated.name - the method's name.desc - the method's descriptor (see Type).signature - the method's signature. May be null if the
method parameters, return type and exceptions do not use generic
types.exceptions - the internal names of the method's exception classes
(see getInternalName). May be
null.protected ASMifierMethodVisitor createASMifierMethodVisitor()
public AnnotationVisitor visitAnnotation(String desc, boolean visible)
ASMifierAbstractVisitorvisitAnnotation in interface ClassVisitorvisitAnnotation in class ASMifierAbstractVisitordesc - the class descriptor of the annotation class.visible - true if the annotation is visible at runtime.public void visitEnd()
ASMifierAbstractVisitorvisitEnd in interface ClassVisitorvisitEnd in class ASMifierAbstractVisitorCopyright © 2009-2013 Oracle Corporation. All Rights Reserved.