org.objectweb.asm.attrs
Class SignatureAttribute
java.lang.Object
org.objectweb.asm.Attribute
org.objectweb.asm.attrs.SignatureAttribute
- Direct Known Subclasses:
- ASMSignatureAttribute
public class SignatureAttribute
- extends Attribute
The Signature Attribute introduced in JSR-14 (Adding Generics to the
Java Programming Language) and also defined in the Java Virtual Machine
Specification, 3rd edition draft. This atribute is used for classes,
fields and methods.
Classfiles need to carry generic type information in a backwards
compatible way. This is accomplished by introducing a new "Signature"
attribute for classes, methods and fields. The structure of this
attribute is as follows:
"Signature" (u4 attr-length, u2 signature-index)
When used as an attribute of a method or field, a signature gives the
full (possibly generic) type of that method or field.
When used as a class attribute, a signature indicates the type
parameters of the class, followed by its supertype, followed by
all its interfaces.
The type syntax in signatures is extended to parameterized types and
type variables. There is also a new signature syntax for formal type
parameters. The syntax extensions for signature strings are as follows:
MethodOrFieldSignature ::= TypeSignature
ClassSignature ::= ParameterPartOpt super_TypeSignature interface_TypeSignatures
TypeSignatures ::= TypeSignatures TypeSignature
|
TypeSignature ::= ...
| ClassTypeSignature
| MethodTypeSignature
| TypeVariableSignature
ClassTypeSignature ::= 'L' Ident TypeArgumentsOpt ';'
| ClassTypeSignature '.' Ident ';' TypeArgumentsOpt
MethodTypeSignature ::= TypeArgumentsOpt '(' TypeSignatures ')'
TypeSignature ThrowsSignatureListOpt
ThrowsSignatureList ::= ThrowsSignature ThrowsSignatureList
| ThrowsSignature
ThrowsSignature ::= '^' TypeSignature
TypeVariableSignature ::= 'T' Ident ';'
TypeArguments ::= '<' TypeSignature TypeSignatures '>'
ParameterPart ::= '<' ParameterSignature ParameterSignatures '>'
ParameterSignatures ::= ParameterSignatures ParameterSignature
|
ParameterSignature ::= Ident ':' bound_TypeSignature
- Author:
- Eugene Kuleshov
- See Also:
- JSR 14 : Add Generic
Types To The JavaTM Programming Language
signature
public String signature
SignatureAttribute
public SignatureAttribute()
SignatureAttribute
public SignatureAttribute(String signature)
read
protected Attribute read(ClassReader cr,
int off,
int len,
char[] buf,
int codeOff,
Label[] labels)
- Description copied from class:
Attribute
- Reads a
type
attribute. This method must return a new
Attribute
object, of type type
, corresponding to the
len bytes starting at the given offset, in the given class reader.
- Overrides:
read
in class Attribute
- Parameters:
cr
- the class that contains the attribute to be read.off
- index of the first byte of the attribute's content in cr.b
. The 6 attribute header bytes, containing the type
and the length of the attribute, are not taken into account here.len
- the length of the attribute's content.buf
- buffer to be used to call readUTF8
,
readClass
or readConst
.codeOff
- index of the first byte of code's attribute content in
cr.b
, or -1 if the attribute to be read is not a
code attribute. The 6 attribute header bytes, containing the type and
the length of the attribute, are not taken into account here.labels
- the labels of the method's code, or null if the
attribute to be read is not a code attribute.
- Returns:
- a new
Attribute
object corresponding to the given
bytes.
write
protected ByteVector write(ClassWriter cw,
byte[] code,
int len,
int maxStack,
int maxLocals)
- Description copied from class:
Attribute
- Returns the byte array form of this attribute.
- Overrides:
write
in class Attribute
- Parameters:
cw
- the class to which this attribute must be added. This parameter
can be used to add to the constant pool of this class the items that
corresponds to this attribute.code
- the bytecode of the method corresponding to this code
attribute, or null if this attribute is not a code
attributes.len
- the length of the bytecode of the method corresponding to this
code attribute, or null if this attribute is not a code
attribute.maxStack
- the maximum stack size of the method corresponding to this
code attribute, or -1 if this attribute is not a code attribute.maxLocals
- the maximum number of local variables of the method
corresponding to this code attribute, or -1 if this attribute is not
a code attribute.
- Returns:
- the byte array form of this attribute.
toString
public String toString()
- Overrides:
toString
in class Object