Package org.objectweb.asm.util

Class TraceClassVisitor

java.lang.Object
org.objectweb.asm.ClassVisitor
org.objectweb.asm.util.TraceClassVisitor
public final class TraceClassVisitor extends ClassVisitor
A ClassVisitor that prints the classes it visits with a Printer. This class visitor can be used in the middle of a class visitor chain to trace the class that is visited at a given point in this chain. This may be useful for debugging purposes.

When used with a Textifier, the trace printed when visiting the Hello class is the following: 

 // class version 49.0 (49) // access flags 0x21 public class Hello {

 // compiled from: Hello.java

 // access flags 0x1
 public <init> ()V
 ALOAD 0
 INVOKESPECIAL java/lang/Object <init> ()V
 RETURN
 MAXSTACK = 1 MAXLOCALS = 1

 // access flags 0x9
 public static main ([Ljava/lang/String;)V
 GETSTATIC java/lang/System out Ljava/io/PrintStream;
 LDC "hello"
 INVOKEVIRTUAL java/io/PrintStream println (Ljava/lang/String;)V
 RETURN
 MAXSTACK = 2 MAXLOCALS = 1
 }

where Hello is defined by: 

 public class Hello {

   public static void main(String[] args) {
     System.out.println("hello");
   }
 }

  • Field Details

    • p

      public final Printer p
      The printer to convert the visited class into text.

  • Constructor Details

    • TraceClassVisitor

      public TraceClassVisitor(PrintWriter printWriter)
      Constructs a new TraceClassVisitor.
      Parameters:
      printWriter - the print writer to be used to print the class. May be null.

    • TraceClassVisitor

      public TraceClassVisitor(ClassVisitor classVisitor, PrintWriter printWriter)
      Constructs a new TraceClassVisitor.
      Parameters:
      classVisitor - the class visitor to which to delegate calls. May be null.
      printWriter - the print writer to be used to print the class. May be null.

    • TraceClassVisitor

      public TraceClassVisitor(ClassVisitor classVisitor, Printer printer, PrintWriter printWriter)
      Constructs a new TraceClassVisitor.
      Parameters:
      classVisitor - the class visitor to which to delegate calls. May be null.
      printer - the printer to convert the visited class into text.
      printWriter - the print writer to be used to print the class. May be null.

  • Method Details

    • visit

      public void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
      Description copied from class: ClassVisitor
      Visits the header of the class.
      Overrides:
      visit in class ClassVisitor
      Parameters:
      version - the class version. The minor version is stored in the 16 most significant bits, and the major version in the 16 least significant bits.
      access - the class's access flags (see Opcodes). This parameter also indicates if the class is deprecated Opcodes.ACC_DEPRECATED or a record Opcodes.ACC_RECORD.
      name - the internal name of the class (see Type.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 Type.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 Type.getInternalName()). May be null.

    • visitSource

      public void visitSource(String file, String debug)
      Description copied from class: ClassVisitor
      Visits the source of the class.
      Overrides:
      visitSource in class ClassVisitor
      Parameters:
      file - the name of the source file from which the class was compiled. May be null.
      debug - additional debug information to compute the correspondence between source and compiled elements of the class. May be null.

    • visitModule

      public ModuleVisitor visitModule(String name, int flags, String version)
      Description copied from class: ClassVisitor
      Visit the module corresponding to the class.
      Overrides:
      visitModule in class ClassVisitor
      Parameters:
      name - the fully qualified name (using dots) of the module.
      flags - the module access flags, among ACC_OPEN, ACC_SYNTHETIC and ACC_MANDATED.
      version - the module version, or null.
      Returns:
      a visitor to visit the module values, or null if this visitor is not interested in visiting this module.

    • visitNestHost

      public void visitNestHost(String nestHost)
      Description copied from class: ClassVisitor
      Visits the nest host class of the class. A nest is a set of classes of the same package that share access to their private members. One of these classes, called the host, lists the other members of the nest, which in turn should link to the host of their nest. This method must be called only once and only if the visited class is a non-host member of a nest. A class is implicitly its own nest, so it's invalid to call this method with the visited class name as argument.
      Overrides:
      visitNestHost in class ClassVisitor
      Parameters:
      nestHost - the internal name of the host class of the nest (see Type.getInternalName()).

    • visitOuterClass

      public void visitOuterClass(String owner, String name, String descriptor)
      Description copied from class: ClassVisitor
      Visits the enclosing class of the class. This method must be called only if this class is a local or anonymous class. See the JVMS 4.7.7 section for more details.
      Overrides:
      visitOuterClass in class ClassVisitor
      Parameters:
      owner - internal name of the enclosing class of the class (see Type.getInternalName()).
      name - the name of the method that contains the class, or null if the class is not enclosed in a method or constructor of its enclosing class (e.g. if it is enclosed in an instance initializer, static initializer, instance variable initializer, or class variable initializer).
      descriptor - the descriptor of the method that contains the class, or null if the class is not enclosed in a method or constructor of its enclosing class (e.g. if it is enclosed in an instance initializer, static initializer, instance variable initializer, or class variable initializer).

    • visitAnnotation

      public AnnotationVisitor visitAnnotation(String descriptor, boolean visible)
      Description copied from class: ClassVisitor
      Visits an annotation of the class.
      Overrides:
      visitAnnotation in class ClassVisitor
      Parameters:
      descriptor - the class descriptor of the annotation class.
      visible - true if the annotation is visible at runtime.
      Returns:
      a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

    • visitTypeAnnotation

      public AnnotationVisitor visitTypeAnnotation(int typeRef, TypePath typePath, String descriptor, boolean visible)
      Description copied from class: ClassVisitor
      Visits an annotation on a type in the class signature.
      Overrides:
      visitTypeAnnotation in class ClassVisitor
      Parameters:
      typeRef - a reference to the annotated type. The sort of this type reference must be TypeReference.CLASS_TYPE_PARAMETER, TypeReference.CLASS_TYPE_PARAMETER_BOUND or TypeReference.CLASS_EXTENDS. See TypeReference.
      typePath - the path to the annotated type argument, wildcard bound, array element type, or static inner type within 'typeRef'. May be null if the annotation targets 'typeRef' as a whole.
      descriptor - the class descriptor of the annotation class.
      visible - true if the annotation is visible at runtime.
      Returns:
      a visitor to visit the annotation values, or null if this visitor is not interested in visiting this annotation.

    • visitAttribute

      public void visitAttribute(Attribute attribute)
      Description copied from class: ClassVisitor
      Visits a non standard attribute of the class.
      Overrides:
      visitAttribute in class ClassVisitor
      Parameters:
      attribute - an attribute.

    • visitNestMember

      public void visitNestMember(String nestMember)
      Description copied from class: ClassVisitor
      Visits a member of the nest. A nest is a set of classes of the same package that share access to their private members. One of these classes, called the host, lists the other members of the nest, which in turn should link to the host of their nest. This method must be called only if the visited class is the host of a nest. A nest host is implicitly a member of its own nest, so it's invalid to call this method with the visited class name as argument.
      Overrides:
      visitNestMember in class ClassVisitor
      Parameters:
      nestMember - the internal name of a nest member (see Type.getInternalName()).

    • visitPermittedSubclass

      public void visitPermittedSubclass(String permittedSubclass)
      Description copied from class: ClassVisitor
      Visits a permitted subclasses. A permitted subclass is one of the allowed subclasses of the current class.
      Overrides:
      visitPermittedSubclass in class ClassVisitor
      Parameters:
      permittedSubclass - the internal name of a permitted subclass (see Type.getInternalName()).

    • visitInnerClass

      public void visitInnerClass(String name, String outerName, String innerName, int access)
      Description copied from class: ClassVisitor
      Visits information about an inner class. This inner class is not necessarily a member of the class being visited. More precisely, every class or interface C which is referenced by this class and which is not a package member must be visited with this method. This class must reference its nested class or interface members, and its enclosing class, if any. See the JVMS 4.7.6 section for more details.
      Overrides:
      visitInnerClass in class ClassVisitor
      Parameters:
      name - the internal name of C (see Type.getInternalName()).
      outerName - the internal name of the class or interface C is a member of (see Type.getInternalName()). Must be null if C is not the member of a class or interface (e.g. for local or anonymous classes).
      innerName - the (simple) name of C. Must be null for anonymous inner classes.
      access - the access flags of C originally declared in the source code from which this class was compiled.

    • visitRecordComponent

      public RecordComponentVisitor visitRecordComponent(String name, String descriptor, String signature)
      Description copied from class: ClassVisitor
      Visits a record component of the class.
      Overrides:
      visitRecordComponent in class ClassVisitor
      Parameters:
      name - the record component name.
      descriptor - the record component descriptor (see Type).
      signature - the record component signature. May be null if the record component type does not use generic types.
      Returns:
      a visitor to visit this record component annotations and attributes, or null if this class visitor is not interested in visiting these annotations and attributes.

    • visitField

      public FieldVisitor visitField(int access, String name, String descriptor, String signature, Object value)
      Description copied from class: ClassVisitor
      Visits a field of the class.
      Overrides:
      visitField in class ClassVisitor
      Parameters:
      access - the field's access flags (see Opcodes). This parameter also indicates if the field is synthetic and/or deprecated.
      name - the field's name.
      descriptor - 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.
      Returns:
      a visitor to visit field annotations and attributes, or null if this class visitor is not interested in visiting these annotations and attributes.

    • visitMethod

      public MethodVisitor visitMethod(int access, String name, String descriptor, String signature, String[] exceptions)
      Description copied from class: ClassVisitor
      Visits a method of the class. This method must return a new MethodVisitor instance (or null) each time it is called, i.e., it should not return a previously returned visitor.
      Overrides:
      visitMethod in class ClassVisitor
      Parameters:
      access - the method's access flags (see Opcodes). This parameter also indicates if the method is synthetic and/or deprecated.
      name - the method's name.
      descriptor - 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 Type.getInternalName()). May be null.
      Returns:
      an object to visit the byte code of the method, or null if this class visitor is not interested in visiting the code of this method.

    • visitEnd

      public void visitEnd()
      Description copied from class: ClassVisitor
      Visits the end of the class. This method, which is the last one to be called, is used to inform the visitor that all the fields and methods of the class have been visited.
      Overrides:
      visitEnd in class ClassVisitor