Class SerialVersionUIDAdder

java.lang.Object
org.objectweb.asm.ClassAdapter
org.objectweb.asm.commons.SerialVersionUIDAdder
All Implemented Interfaces:
ClassVisitor
public class SerialVersionUIDAdder extends ClassAdapter
A ClassAdapter that adds a serial version unique identifier to a class if missing. Here is typical usage of this class: 
  ClassWriter cw = new ClassWriter(...);
  ClassVisitor sv = new SerialVersionUIDAdder(cw);
  ClassVisitor ca = new MyClassAdapter(sv);
  new ClassReader(orginalClass).accept(ca, false);
The SVUID algorithm can be found http://java.sun.com/j2se/1.4.2/docs/guide/serialization/spec/class.html: 
The serialVersionUID is computed using the signature of a stream of bytes
that reflect the class definition. The National Institute of Standards and
Technology (NIST) Secure Hash Algorithm (SHA-1) is used to compute a
signature for the stream. The first two 32-bit quantities are used to form a
64-bit hash. A java.lang.DataOutputStream is used to convert primitive data
types to a sequence of bytes. The values input to the stream are defined by
the Java Virtual Machine (VM) specification for classes.

The sequence of items in the stream is as follows:

1. The class name written using UTF encoding.
2. The class modifiers written as a 32-bit integer.
3. The name of each interface sorted by name written using UTF encoding.
4. For each field of the class sorted by field name (except private static
and private transient fields):
1. The name of the field in UTF encoding.
2. The modifiers of the field written as a 32-bit integer.
3. The descriptor of the field in UTF encoding
5. If a class initializer exists, write out the following:
1. The name of the method, <clinit>, in UTF encoding.
2. The modifier of the method, java.lang.reflect.Modifier.STATIC,
written as a 32-bit integer.
3. The descriptor of the method, ()V, in UTF encoding.
6. For each non-private constructor sorted by method name and signature:
1. The name of the method, <init>, in UTF encoding.
2. The modifiers of the method written as a 32-bit integer.
3. The descriptor of the method in UTF encoding.
7. For each non-private method sorted by method name and signature:
1. The name of the method in UTF encoding.
2. The modifiers of the method written as a 32-bit integer.
3. The descriptor of the method in UTF encoding.
8. The SHA-1 algorithm is executed on the stream of bytes produced by
DataOutputStream and produces five 32-bit values sha[0..4].

9. The hash value is assembled from the first and second 32-bit values of 
the SHA-1 message digest. If the result of the message digest, the five
32-bit words H0 H1 H2 H3 H4, is in an array of five int values named 
sha, the hash value would be computed as follows:

long hash = ((sha[0] >>> 24) & 0xFF) |
((sha[0] >>> 16) & 0xFF) << 8 |
((sha[0] >>> 8) & 0xFF) << 16 |
((sha[0] >>> 0) & 0xFF) << 24 |
((sha[1] >>> 24) & 0xFF) << 32 |
((sha[1] >>> 16) & 0xFF) << 40 |
((sha[1] >>> 8) & 0xFF) << 48 |
((sha[1] >>> 0) & 0xFF) << 56;
Author:
Rajendra Inamdar, Vishal Vishnoi

  • Field Details

    • computeSVUID

      protected boolean computeSVUID
      Flag that indicates if we need to compute SVUID.

    • hasSVUID

      protected boolean hasSVUID
      Set to true if the class already has SVUID.

    • access

      protected int access
      Classes access flags.

    • name

      protected String name
      Internal name of the class

    • interfaces

      protected String[] interfaces
      Interfaces implemented by the class.

    • svuidFields

      protected Collection svuidFields
      Collection of fields. (except private static and private transient fields)

    • hasStaticInitializer

      protected boolean hasStaticInitializer
      Set to true if the class has static initializer.

    • svuidConstructors

      protected Collection svuidConstructors
      Collection of non-private constructors.

    • svuidMethods

      protected Collection svuidMethods
      Collection of non-private methods.

  • Constructor Details

  • Method Details

    • visit

      public void visit(int version, int access, String name, String signature, String superName, String[] interfaces)
      Description copied from interface: ClassVisitor
      Visits the header of the class.
      Specified by:
      visit in interface ClassVisitor
      Overrides:
      visit in class ClassAdapter
      Parameters:
      version - 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.

    • visitMethod

      public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions)
      Description copied from interface: 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.
      Specified by:
      visitMethod in interface ClassVisitor
      Overrides:
      visitMethod in class ClassAdapter
      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.
      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.
      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.

    • visitField

      public FieldVisitor visitField(int access, String name, String desc, String signature, Object value)
      Description copied from interface: ClassVisitor
      Visits a field of the class.
      Specified by:
      visitField in interface ClassVisitor
      Overrides:
      visitField in class ClassAdapter
      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.
      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.
      Returns:
      a visitor to visit field annotations and attributes, or null if this class visitor is not interested in visiting these annotations and attributes.

    • visitInnerClass

      public void visitInnerClass(String aname, String outerName, String innerName, int attr_access)
      Handle a bizarre special case. Nested classes (static classes declared inside another class) that are protected have their access bit set to public in their class files to deal with some odd reflection situation. Our SVUID computation must do as the JVM does and ignore access bits in the class file in favor of the access bits InnerClass attribute.
      Specified by:
      visitInnerClass in interface ClassVisitor
      Overrides:
      visitInnerClass in class ClassAdapter
      Parameters:
      aname - 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.
      attr_access - the access flags of the inner class as originally declared in the enclosing class.

    • visitEnd

      public void visitEnd()
      Description copied from interface: 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.
      Specified by:
      visitEnd in interface ClassVisitor
      Overrides:
      visitEnd in class ClassAdapter

    • computeSVUID

      protected long computeSVUID() throws IOException
      Returns the value of SVUID if the class doesn't have one already. Please note that 0 is returned if the class already has SVUID, thus use isHasSVUID to determine if the class already had an SVUID.
      Returns:
      Returns the serial version UID
      Throws:
      IOException

    • computeSHAdigest

      protected byte[] computeSHAdigest(byte[] value)
      Returns the SHA-1 message digest of the given value.
      Parameters:
      value - the value whose SHA message digest must be computed.
      Returns:
      the SHA-1 message digest of the given value.