org.objectweb.asm

Class Attribute

Known Direct Subclasses:
AnnotationDefaultAttribute, EnclosingMethodAttribute, LocalVariableTypeTableAttribute, RuntimeInvisibleAnnotations, RuntimeInvisibleParameterAnnotations, RuntimeVisibleAnnotations, RuntimeVisibleParameterAnnotations, SignatureAttribute, SourceDebugExtensionAttribute, StackMapAttribute

public class Attribute
extends Object

A non standard class, field, method or code attribute.
Author:
Eric Bruneton, Eugene Kuleshov

Field Summary

Attribute
next
The next attribute in this attribute list.
String
type
The type of this attribute.

Constructor Summary

Attribute(String type)
Constructs a new empty attribute.

Method Summary

protected Label[]
getLabels()
Returns the labels corresponding to this attribute.
boolean
isUnknown()
Returns true if this type of attribute is unknown.
protected Attribute
read(ClassReader cr, int off, int len, char[] buf, int codeOff, Label[] labels)
Reads a type attribute.
protected ByteVector
write(ClassWriter cw, byte[] code, int len, int maxStack, int maxLocals)
Returns the byte array form of this attribute.

Field Details

Attribute next
The next attribute in this attribute list. May be null.

type

public final String type
The type of this attribute.

Constructor Details

Attribute

protected Attribute(String type)
Constructs a new empty attribute.
Parameters:
type - the type of the attribute.

Method Details

getLabels

protected Label[] getLabels()
Returns the labels corresponding to this attribute.
Returns:
the labels corresponding to this attribute, or null if this attribute is not a code attribute that contains labels.

isUnknown

public boolean isUnknown()
Returns true if this type of attribute is unknown.

read

protected Attribute read(ClassReader cr,
                         int off,
                         int len,
                         char[] buf,
                         int codeOff,
                         Label[] labels)
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.
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)
Returns the byte array form of this 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.