org.objectweb.asm
Class ClassReader
A Java class parser to make a
ClassVisitor
visit an existing class.
This class parses a byte array conforming to the Java class file format and
calls the appropriate visit methods of a given class visitor for each field,
method and bytecode instruction encountered.
- Eric Bruneton
- Eugene Kuleshov
byte[] | b - The class to be parsed.
|
int | header - Start index of the class header information (access, name...) in
b .
|
void | accept(ClassVisitor classVisitor, boolean skipDebug) - Makes the given visitor visit the Java class of this
ClassReader .
|
void | accept(ClassVisitor classVisitor, Attribute[] attrs, boolean skipDebug) - Makes the given visitor visit the Java class of this
ClassReader .
|
int | getItem(int item) - Returns the start index of the constant pool item in
b , plus
one.
|
int | readByte(int index) - Reads a byte value in
b .
|
String | readClass(int index, char[] buf) - Reads a class constant pool item in
b .
|
Object | readConst(int item, char[] buf) - Reads a numeric or string constant pool item in
b .
|
int | readInt(int index) - Reads a signed int value in
b .
|
long | readLong(int index) - Reads a signed long value in
b .
|
short | readShort(int index) - Reads a signed short value in
b .
|
String | readUTF8(int index, char[] buf) - Reads an UTF8 string constant pool item in
b .
|
int | readUnsignedShort(int index) - Reads an unsigned short value in
b .
|
b
public final byte[] b
The class to be parsed.
The content of this array must not be
modified. This field is intended for Attribute
sub classes, and
is normally not needed by class generators or adapters.
header
public final int header
Start index of the class header information (access, name...) in
b
.
ClassReader
public ClassReader(InputStream is)
throws IOException
is
- an input stream from which to read the class.
ClassReader
public ClassReader(String name)
throws IOException
name
- the fully qualified name of the class to be read.
ClassReader
public ClassReader(byte[] b)
b
- the bytecode of the class to be read.
ClassReader
public ClassReader(byte[] b,
int off,
int len)
b
- the bytecode of the class to be read.off
- the start offset of the class data.len
- the length of the class data.
accept
public void accept(ClassVisitor classVisitor,
boolean skipDebug)
Makes the given visitor visit the Java class of this
ClassReader
.
This class is the one specified in the constructor (see
ClassReader
).
classVisitor
- the visitor that must visit this class.skipDebug
- true if the debug information of the class
must not be visited. In this case the
visitLocalVariable
and
visitLineNumber
methods will
not be called.
accept
public void accept(ClassVisitor classVisitor,
Attribute[] attrs,
boolean skipDebug)
Makes the given visitor visit the Java class of this
ClassReader
.
This class is the one specified in the constructor (see
ClassReader
).
classVisitor
- the visitor that must visit this class.attrs
- prototypes of the attributes that must be parsed during the
visit of the class. Any attribute whose type is not equal to the
type of one the prototypes will be ignored.skipDebug
- true if the debug information of the class
must not be visited. In this case the
visitLocalVariable
and
visitLineNumber
methods will
not be called.
getItem
public int getItem(int item)
Returns the start index of the constant pool item in
b
, plus
one.
This method is intended for Attribute
sub classes, and is
normally not needed by class generators or adapters.
item
- the index a constant pool item.
- the start index of the constant pool item in
b
, plus
one.
readByte
public int readByte(int index)
Reads a byte value in
b
.
This method is intended for
Attribute
sub classes, and is normally not needed by class
generators or adapters.
index
- the start index of the value to be read in b
.
readClass
public String readClass(int index,
char[] buf)
Reads a class constant pool item in
b
.
This method is
intended for Attribute
sub classes, and is normally not needed by
class generators or adapters.
index
- the start index of an unsigned short value in b
,
whose value is the index of a class constant pool item.buf
- buffer to be used to read the item. This buffer must be
sufficiently large. It is not automatically resized.
- the String corresponding to the specified class item.
readConst
public Object readConst(int item,
char[] buf)
Reads a numeric or string constant pool item in
b
.
This
method is intended for Attribute
sub classes, and is normally not
needed by class generators or adapters.
item
- the index of a constant pool item.buf
- buffer to be used to read the item. This buffer must be
sufficiently large. It is not automatically resized.
- the
Integer
, Float
, Long
,
Double
, String
or Type
corresponding to
the given constant pool item.
readInt
public int readInt(int index)
Reads a signed int value in
b
.
This method is intended for
Attribute
sub classes, and is normally not needed by class
generators or adapters.
index
- the start index of the value to be read in b
.
readLong
public long readLong(int index)
Reads a signed long value in
b
.
This method is intended
for Attribute
sub classes, and is normally not needed by class
generators or adapters.
index
- the start index of the value to be read in b
.
readShort
public short readShort(int index)
Reads a signed short value in
b
.
This method is intended
for Attribute
sub classes, and is normally not needed by class
generators or adapters.
index
- the start index of the value to be read in b
.
readUTF8
public String readUTF8(int index,
char[] buf)
Reads an UTF8 string constant pool item in
b
.
This method
is intended for Attribute
sub classes, and is normally not needed
by class generators or adapters.
index
- the start index of an unsigned short value in b
,
whose value is the index of an UTF8 constant pool item.buf
- buffer to be used to read the item. This buffer must be
sufficiently large. It is not automatically resized.
- the String corresponding to the specified UTF8 item.
readUnsignedShort
public int readUnsignedShort(int index)
Reads an unsigned short value in
b
.
This method is
intended for Attribute
sub classes, and is normally not needed by
class generators or adapters.
index
- the start index of the value to be read in b
.