Package javassist.bytecode

Class CodeAttribute

java.lang.Object

javassist.bytecode.AttributeInfo

javassist.bytecode.CodeAttribute

All Implemented Interfaces:

Opcode

public class CodeAttribute
extends AttributeInfo
implements Opcode

Code_attribute.

To browse the code field of a Code_attribute structure, use CodeIterator.

See Also:

• CodeIterator
• iterator()

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	CodeAttribute.LdcEntry
static class	CodeAttribute.RuntimeCopyException	An exception that may be thrown by copy() in CodeAttribute.

Field Summary

Fields

Modifier and Type	Field	Description
private List<AttributeInfo>	attributes
private ExceptionTable	exceptions
private int	maxLocals
private int	maxStack
static final String	tag	The name of this attribute "Code".

Fields inherited from class javassist.bytecode.AttributeInfo

constPool, info, name

Fields inherited from interface javassist.bytecode.Opcode

AALOAD, AASTORE, ACONST_NULL, ALOAD, ALOAD_0, ALOAD_1, ALOAD_2, ALOAD_3, ANEWARRAY, ARETURN, ARRAYLENGTH, ASTORE, ASTORE_0, ASTORE_1, ASTORE_2, ASTORE_3, ATHROW, BALOAD, BASTORE, BIPUSH, CALOAD, CASTORE, CHECKCAST, D2F, D2I, D2L, DADD, DALOAD, DASTORE, DCMPG, DCMPL, DCONST_0, DCONST_1, DDIV, DLOAD, DLOAD_0, DLOAD_1, DLOAD_2, DLOAD_3, DMUL, DNEG, DREM, DRETURN, DSTORE, DSTORE_0, DSTORE_1, DSTORE_2, DSTORE_3, DSUB, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, F2D, F2I, F2L, FADD, FALOAD, FASTORE, FCMPG, FCMPL, FCONST_0, FCONST_1, FCONST_2, FDIV, FLOAD, FLOAD_0, FLOAD_1, FLOAD_2, FLOAD_3, FMUL, FNEG, FREM, FRETURN, FSTORE, FSTORE_0, FSTORE_1, FSTORE_2, FSTORE_3, FSUB, GETFIELD, GETSTATIC, GOTO, GOTO_W, I2B, I2C, I2D, I2F, I2L, I2S, IADD, IALOAD, IAND, IASTORE, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, ICONST_M1, IDIV, IF_ACMPEQ, IF_ACMPNE, IF_ICMPEQ, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ICMPLT, IF_ICMPNE, IFEQ, IFGE, IFGT, IFLE, IFLT, IFNE, IFNONNULL, IFNULL, IINC, ILOAD, ILOAD_0, ILOAD_1, ILOAD_2, ILOAD_3, IMUL, INEG, INSTANCEOF, INVOKEDYNAMIC, INVOKEINTERFACE, INVOKESPECIAL, INVOKESTATIC, INVOKEVIRTUAL, IOR, IREM, IRETURN, ISHL, ISHR, ISTORE, ISTORE_0, ISTORE_1, ISTORE_2, ISTORE_3, ISUB, IUSHR, IXOR, JSR, JSR_W, L2D, L2F, L2I, LADD, LALOAD, LAND, LASTORE, LCMP, LCONST_0, LCONST_1, LDC, LDC_W, LDC2_W, LDIV, LLOAD, LLOAD_0, LLOAD_1, LLOAD_2, LLOAD_3, LMUL, LNEG, LOOKUPSWITCH, LOR, LREM, LRETURN, LSHL, LSHR, LSTORE, LSTORE_0, LSTORE_1, LSTORE_2, LSTORE_3, LSUB, LUSHR, LXOR, MONITORENTER, MONITOREXIT, MULTIANEWARRAY, NEW, NEWARRAY, NOP, POP, POP2, PUTFIELD, PUTSTATIC, RET, RETURN, SALOAD, SASTORE, SIPUSH, STACK_GROW, SWAP, T_BOOLEAN, T_BYTE, T_CHAR, T_DOUBLE, T_FLOAT, T_INT, T_LONG, T_SHORT, TABLESWITCH, WIDE

Constructor Summary

Constructors

Modifier	Constructor	Description
	CodeAttribute(ConstPool cp, int stack, int locals, byte[] code, ExceptionTable etable)	Constructs a Code_attribute.
(package private)	CodeAttribute(ConstPool cp, int name_id, DataInputStream in)
private	CodeAttribute(ConstPool cp, CodeAttribute src, Map<String,String> classnames)	Constructs a copy of Code_attribute.

Method Summary

Modifier and Type	Method	Description
private static boolean	checkStaticMethodExisted(CtClass ctClass, String staticMethodName, String staticMethodSignature)
int	computeMaxStack()	Computes the maximum stack size and sets max_stack to the computed size.
AttributeInfo	copy(ConstPool newCp, Map<String,String> classnames)	Makes a copy.
private static void	copyBootstrapMethod(ConstPool srcCp, ConstPool destCp, int codeIndex, byte[] srcCode, byte[] newCode, Map<String,String> classnameMap)	Copy the Bootstrap method of the specified index referenced in the source InvokeDynamic directive to the specified index in the destination Boostrap Attribute. if the Bootstrap Attribute does not exist in the destination class, create a new Bootstrap Attribute; if the destination Bootstrap Method already exists at the specified index method, the method at that position will be overwritten, otherwise it will be added at the end of the destination Bootstrap method.
private static CodeAttribute.LdcEntry	copyCode(byte[] code, int beginPos, int endPos, ConstPool srcCp, byte[] newcode, ConstPool destCp, Map<String,String> classnameMap)
private byte[]	copyCode(ConstPool destCp, Map<String,String> classnames, ExceptionTable etable, CodeAttribute destCa)	Copies code.
private static void	copyConstPoolInfo(int i, byte[] code, ConstPool srcCp, byte[] newcode, ConstPool destCp, Map<String,String> classnameMap)
private static void	copyInvokeStaticMethod(CtClass srcCc, ConstPool srcCp, BootstrapMethodsAttribute.BootstrapMethod srcBm, CtClass destCc, Map<String,String> classnameMap)	Copy the static methods referenced by the bootstrap method in this class (such as some lambda methods). If the source method exists in the destination class, it will be ignored.
byte[]	get()	This method is not available.
AttributeInfo	getAttribute(String name)	Returns the attribute with the specified name.
List<AttributeInfo>	getAttributes()	Returns attributes[].
byte[]	getCode()	Returns code[].
int	getCodeLength()	Returns code_length.
String	getDeclaringClass()	Returns the name of the class declaring the method including this code attribute.
ExceptionTable	getExceptionTable()	Returns exception_table[].
int	getMaxLocals()	Returns max_locals.
int	getMaxStack()	Returns max_stack.
(package private) void	getRefClasses(Map<String,String> classnames)
private static CtMethod	getStaticCtMethod(CtClass ctClass, String staticMethodName, String staticMethodSignature)
void	insertLocalVar(int where, int size)	Changes the index numbers of the local variables to append a new parameter.
CodeIterator	iterator()	Makes a new iterator for reading this code attribute.
int	length()	Returns the length of this attribute_info structure.
(package private) void	renameClass(String oldname, String newname)
(package private) void	renameClass(Map<String,String> classnames)
void	set(byte[] newinfo)	This method is not available.
void	setAttribute(LineNumberAttribute lnt)	Adds a line number table.
void	setAttribute(StackMap sm)	Adds a stack map table for J2ME (CLDC).
void	setAttribute(StackMapTable smt)	Adds a stack map table.
(package private) void	setCode(byte[] newinfo)	Sets code[].
void	setMaxLocals(int value)	Sets max_locals.
void	setMaxStack(int value)	Sets max_stack.
private static void	shiftIndex(CodeIterator ci, int lessThan, int delta)
private static void	shiftIndex0(CodeIterator ci, int index, int opcode, int lessThan, int delta, int opcode_i_0, int opcode_i)
private static void	shiftIndex8(CodeIterator ci, int index, int opcode, int lessThan, int delta)
(package private) void	write(DataOutputStream out)

Methods inherited from class javassist.bytecode.AttributeInfo

copyAll, getConstPool, getLength, getName, getRefClasses, lookup, read, remove, renameClass, renameClass, writeAll

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

tag

public static final String tag

The name of this attribute "Code".

See Also:

• Constant Field Values

maxStack

private int maxStack

maxLocals

private int maxLocals

exceptions

private ExceptionTable exceptions

attributes

private List<AttributeInfo> attributes

Constructor Details

CodeAttribute

public CodeAttribute(ConstPool cp,
 int stack,
 int locals,
 byte[] code,
 ExceptionTable etable)

Constructs a Code_attribute.

Parameters:

cp - constant pool table

stack - max_stack

locals - max_locals

code - code[]

etable - exception_table[]

CodeAttribute

private CodeAttribute(ConstPool cp,
 CodeAttribute src,
 Map<String,String> classnames)
               throws BadBytecode,
NotFoundException,
CannotCompileException

Constructs a copy of Code_attribute. Specified class names are replaced during the copy.

Parameters:

cp - constant pool table.

src - source Code attribute.

classnames - pairs of replaced and substituted class names.

Throws:

BadBytecode

NotFoundException

CannotCompileException

CodeAttribute

CodeAttribute(ConstPool cp,
 int name_id,
 DataInputStream in)
       throws IOException

Throws:

IOException

Method Details

copy

public AttributeInfo copy(ConstPool newCp,
 Map<String,String> classnames)
                   throws CodeAttribute.RuntimeCopyException

Makes a copy. Class names are replaced according to the given Map object.

Overrides:

copy in class AttributeInfo

Parameters:

newCp - the constant pool table used by the new copy.

classnames - pairs of replaced and substituted class names.

Returns:

CodeAttribute object.

Throws:

CodeAttribute.RuntimeCopyException - if a BadBytecode exception is thrown, it is converted into RuntimeCopyException.

length

public int length()

Returns the length of this attribute_info structure. The returned value is attribute_length + 6.

Overrides:

length in class AttributeInfo

write

void write(DataOutputStream out)
    throws IOException

Overrides:

write in class AttributeInfo

Throws:

IOException

get

public byte[] get()

This method is not available.

Overrides:

get in class AttributeInfo

Throws:

UnsupportedOperationException - always thrown.

set

public void set(byte[] newinfo)

This method is not available.

Overrides:

set in class AttributeInfo

Throws:

UnsupportedOperationException - always thrown.

renameClass

void renameClass(String oldname,
 String newname)

Overrides:

renameClass in class AttributeInfo

renameClass

void renameClass(Map<String,String> classnames)

Overrides:

renameClass in class AttributeInfo

getRefClasses

void getRefClasses(Map<String,String> classnames)

Overrides:

getRefClasses in class AttributeInfo

getDeclaringClass

public String getDeclaringClass()

Returns the name of the class declaring the method including this code attribute.

getMaxStack

public int getMaxStack()

Returns max_stack.

setMaxStack

public void setMaxStack(int value)

Sets max_stack.

computeMaxStack

public int computeMaxStack()
                    throws BadBytecode

Computes the maximum stack size and sets max_stack to the computed size.

Returns:

the newly computed value of max_stack

Throws:

BadBytecode - if this method fails in computing.

getMaxLocals

public int getMaxLocals()

Returns max_locals.

setMaxLocals

public void setMaxLocals(int value)

Sets max_locals.

getCodeLength

public int getCodeLength()

Returns code_length.

getCode

public byte[] getCode()

Returns code[].

setCode

void setCode(byte[] newinfo)

Sets code[].

iterator

public CodeIterator iterator()

Makes a new iterator for reading this code attribute.

getExceptionTable

public ExceptionTable getExceptionTable()

Returns exception_table[].

getAttributes

public List<AttributeInfo> getAttributes()

Returns attributes[]. It returns a list of AttributeInfo. A new element can be added to the returned list and an existing element can be removed from the list.

See Also:

• AttributeInfo

getAttribute

public AttributeInfo getAttribute(String name)

Returns the attribute with the specified name. If it is not found, this method returns null.

Parameters:

name - attribute name

Returns:

an AttributeInfo object or null.

setAttribute

public void setAttribute(StackMapTable smt)

Adds a stack map table. If another copy of stack map table is already contained, the old one is removed.

Parameters:

smt - the stack map table added to this code attribute. If it is null, a new stack map is not added. Only the old stack map is removed.

setAttribute

public void setAttribute(StackMap sm)

Adds a stack map table for J2ME (CLDC). If another copy of stack map table is already contained, the old one is removed.

Parameters:

sm - the stack map table added to this code attribute. If it is null, a new stack map is not added. Only the old stack map is removed.

Since:

3.12

setAttribute

public void setAttribute(LineNumberAttribute lnt)

Adds a line number table. If another copy of line number table is already contained, the old one is removed.

Parameters:

lnt - the line number table added to this code attribute. If it is null, a new line number is not added. Only the old line number is removed.

copyCode

private byte[] copyCode(ConstPool destCp,
 Map<String,String> classnames,
 ExceptionTable etable,
 CodeAttribute destCa)
                 throws BadBytecode,
NotFoundException,
CannotCompileException

Copies code.

Throws:

BadBytecode

NotFoundException

CannotCompileException

copyCode

private static CodeAttribute.LdcEntry copyCode(byte[] code,
 int beginPos,
 int endPos,
 ConstPool srcCp,
 byte[] newcode,
 ConstPool destCp,
 Map<String,String> classnameMap)
                                        throws BadBytecode,
NotFoundException,
CannotCompileException

Throws:

BadBytecode

NotFoundException

CannotCompileException

copyBootstrapMethod

private static void copyBootstrapMethod(ConstPool srcCp,
 ConstPool destCp,
 int codeIndex,
 byte[] srcCode,
 byte[] newCode,
 Map<String,String> classnameMap)
                                 throws NotFoundException,
CannotCompileException

Copy the Bootstrap method of the specified index referenced in the source InvokeDynamic directive to the specified index in the destination Boostrap Attribute.
if the Bootstrap Attribute does not exist in the destination class, create a new Bootstrap Attribute;
if the destination Bootstrap Method already exists at the specified index method, the method at that position will be overwritten, otherwise it will be added at the end of the destination Bootstrap method.

Parameters:

srcCp - the constant pool table of source

destCp - the constant pool table of destination

codeIndex - the index of the invoke dynamic first parameter in code array

srcCode - the code array of source

newCode - the code array of destination

classnameMap - pairs of replaced and substituted class names.

Throws:

NotFoundException - this exception thrown when the class cannot be found in the default ClassPool

CannotCompileException - this exception thrown from the method copyInvokeStaticMethod(CtClass, ConstPool, BootstrapMethodsAttribute.BootstrapMethod, CtClass, Map)

copyInvokeStaticMethod

private static void copyInvokeStaticMethod(CtClass srcCc,
 ConstPool srcCp,
 BootstrapMethodsAttribute.BootstrapMethod srcBm,
 CtClass destCc,
 Map<String,String> classnameMap)
                                    throws CannotCompileException

Copy the static methods referenced by the bootstrap method in this class (such as some lambda methods).
If the source method exists in the destination class, it will be ignored.

Parameters:

srcCc - source class

srcCp - constant pool table of source class

srcBm - source method to be copied

destCc - destination class

classnameMap - irs of replaced and substituted class names.

Throws:

CannotCompileException - thrown by CtNewMethod.copy(CtMethod, CtClass, ClassMap) orCtClass.addMethod(CtMethod)

getStaticCtMethod

private static CtMethod getStaticCtMethod(CtClass ctClass,
 String staticMethodName,
 String staticMethodSignature)

checkStaticMethodExisted

private static boolean checkStaticMethodExisted(CtClass ctClass,
 String staticMethodName,
 String staticMethodSignature)

copyConstPoolInfo

private static void copyConstPoolInfo(int i,
 byte[] code,
 ConstPool srcCp,
 byte[] newcode,
 ConstPool destCp,
 Map<String,String> classnameMap)

insertLocalVar

public void insertLocalVar(int where,
 int size)
                    throws BadBytecode

Changes the index numbers of the local variables to append a new parameter. This method does not update LocalVariableAttribute, LocalVariableTypeAttribute, StackMapTable, or StackMap. These attributes must be explicitly updated.

Parameters:

where - the index of the new parameter.

size - the type size of the new parameter (1 or 2).

Throws:

BadBytecode

See Also:

• LocalVariableAttribute.shiftIndex(int, int)
• LocalVariableAttribute.shiftIndex(int, int)
• StackMapTable.insertLocal(int, int, int)
• StackMap.insertLocal(int, int, int)

shiftIndex

private static void shiftIndex(CodeIterator ci,
 int lessThan,
 int delta)
                        throws BadBytecode

Parameters:

lessThan - If the index of the local variable is less than this value, it does not change. Otherwise, the index is increased.

delta - the indexes of the local variables are increased by this value.

Throws:

BadBytecode

shiftIndex8

private static void shiftIndex8(CodeIterator ci,
 int index,
 int opcode,
 int lessThan,
 int delta)
                         throws BadBytecode

Throws:

BadBytecode

shiftIndex0

private static void shiftIndex0(CodeIterator ci,
 int index,
 int opcode,
 int lessThan,
 int delta,
 int opcode_i_0,
 int opcode_i)
                         throws BadBytecode

Throws:

BadBytecode