public class SerialVersionUIDAdder extends ClassVisitor
ClassVisitor 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;
api, cv| 限定符 | 构造器和说明 |
|---|---|
|
SerialVersionUIDAdder(ClassVisitor cv)
Creates a new
SerialVersionUIDAdder. |
protected |
SerialVersionUIDAdder(int api,
ClassVisitor cv)
Creates a new
SerialVersionUIDAdder. |
| 限定符和类型 | 方法和说明 |
|---|---|
protected void |
addSVUID(long svuid) |
protected byte[] |
computeSHAdigest(byte[] value)
Returns the SHA-1 message digest of the given value.
|
protected long |
computeSVUID()
Computes and returns the value of SVUID.
|
boolean |
hasSVUID()
Returns true if the class already has a SVUID field.
|
void |
visit(int version,
int access,
java.lang.String name,
java.lang.String signature,
java.lang.String superName,
java.lang.String[] interfaces)
Visits the header of the class.
|
void |
visitEnd()
Visits the end of the class.
|
FieldVisitor |
visitField(int access,
java.lang.String name,
java.lang.String desc,
java.lang.String signature,
java.lang.Object value)
Visits a field of the class.
|
void |
visitInnerClass(java.lang.String aname,
java.lang.String outerName,
java.lang.String innerName,
int attr_access)
Handle a bizarre special case.
|
MethodVisitor |
visitMethod(int access,
java.lang.String name,
java.lang.String desc,
java.lang.String signature,
java.lang.String[] exceptions)
Visits a method of the class.
|
visitAnnotation, visitAttribute, visitOuterClass, visitSourcepublic SerialVersionUIDAdder(ClassVisitor cv)
SerialVersionUIDAdder. Subclasses must not use this constructor.
Instead, they must use the SerialVersionUIDAdder(int, ClassVisitor) version.cv - a ClassVisitor to which this visitor will delegate calls.protected SerialVersionUIDAdder(int api,
ClassVisitor cv)
SerialVersionUIDAdder.api - the ASM API version implemented by this visitor. Must be one of
Opcodes.ASM4.cv - a ClassVisitor to which this visitor will delegate calls.public void visit(int version,
int access,
java.lang.String name,
java.lang.String signature,
java.lang.String superName,
java.lang.String[] interfaces)
ClassVisitorvisit 在类中 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 MethodVisitor visitMethod(int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.String[] exceptions)
ClassVisitorMethodVisitor
instance (or null) each time it is called, i.e., it should not return a previously
returned visitor.visitMethod 在类中 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.public FieldVisitor visitField(int access, java.lang.String name, java.lang.String desc, java.lang.String signature, java.lang.Object value)
ClassVisitorvisitField 在类中 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 void visitInnerClass(java.lang.String aname,
java.lang.String outerName,
java.lang.String innerName,
int attr_access)
visitInnerClass 在类中 ClassVisitoraname - 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.public void visitEnd()
ClassVisitorvisitEnd 在类中 ClassVisitorpublic boolean hasSVUID()
protected void addSVUID(long svuid)
protected long computeSVUID()
throws java.io.IOException
java.io.IOException - if an I/O error occursprotected byte[] computeSHAdigest(byte[] value)
value - the value whose SHA message digest must be computed.