org.objectweb.asm

Class Attribute

public class Attribute extends Object

A non standard class, field, method or code attribute.

Author: Eric Bruneton Eugene Kuleshov

Field Summary
Stringtype
The type of this attribute.
Constructor Summary
protected Attribute(String type)
Constructs a new empty attribute.
Method Summary
protected Label[]getLabels()
Returns the labels corresponding to this attribute.
booleanisCodeAttribute()
Returns true if this type of attribute is a code attribute.
booleanisUnknown()
Returns true if this type of attribute is unknown.
protected Attributeread(ClassReader cr, int off, int len, char[] buf, int codeOff, Label[] labels)
Reads a {@link #type type} attribute.
protected ByteVectorwrite(ClassWriter cw, byte[] code, int len, int maxStack, int maxLocals)
Returns the byte array form of this attribute.

Field Detail

type

public final String type
The type of this attribute.

Constructor Detail

Attribute

protected Attribute(String type)
Constructs a new empty attribute.

Parameters: type the type of the attribute.

Method Detail

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.

isCodeAttribute

public boolean isCodeAttribute()
Returns true if this type of attribute is a code attribute.

Returns: true if this type of attribute is a code attribute.

isUnknown

public boolean isUnknown()
Returns true if this type of attribute is unknown. The default implementation of this method always returns true.

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 {@link #type type} attribute. This method must return a new {@link Attribute} object, of type {@link #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 {@link ClassReader#b 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 {@link ClassReader#readUTF8 readUTF8}, {@link ClassReader#readClass(int,char[]) readClass} or {@link ClassReader#readConst readConst}. codeOff index of the first byte of code's attribute content in {@link ClassReader#b 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 {@link 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.