org.objectweb.asm.commons
Class SerialVersionUIDAdder
- ClassVisitor
public class SerialVersionUIDAdder
A
ClassAdapter
that adds a serial version unique identifier to a
class if missing. 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, , 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, , 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;
- Rajendra Inamdar, Vishal Vishnoi
protected int | access - Classes access flags.
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protected boolean | computeSVUID - Flag that indicates if we need to compute SVUID.
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protected boolean | hasSVUID - Set to true if the class already has SVUID.
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protected boolean | hasStaticInitializer - Set to true if the class has static initializer.
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protected String[] | interfaces - Interfaces implemented by the class.
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protected String | name - Internal name of the class
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protected Collection | svuidConstructors - Collection of non-private constructors.
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protected Collection | svuidFields - Collection of fields.
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protected Collection | svuidMethods - Collection of non-private methods.
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protected long | computeSVUID() - Returns the value of SVUID if the class doesn't have one already.
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void | visit(int version, int access, String name, String signature, String superName, String[] interfaces)
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void | visitEnd()
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FieldVisitor | visitField(int access, String name, String desc, String signature, Object value)
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MethodVisitor | visitMethod(int access, String name, String desc, String signature, String[] exceptions)
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access
protected int access
Classes access flags.
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.
hasStaticInitializer
protected boolean hasStaticInitializer
Set to true if the class has static initializer.
interfaces
protected String[] interfaces
Interfaces implemented by the class.
name
protected String name
Internal name of the class
svuidConstructors
protected Collection svuidConstructors
Collection of non-private constructors.
svuidFields
protected Collection svuidFields
Collection of fields. (except private static and private transient fields)
svuidMethods
protected Collection svuidMethods
Collection of non-private methods.
SerialVersionUIDAdder
public SerialVersionUIDAdder(ClassVisitor cv)
cv
- a ClassVisitor
to which this visitor will delegate calls.
computeSVUID
protected long computeSVUID()
throws IOException,
NoSuchAlgorithmException
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 the serial version UID
visit
public void visit(int version,
int access,
String name,
String signature,
String superName,
String[] interfaces)
- visit in interface ClassVisitor
- visit in interface ClassAdapter