org.objectweb.asm.util
Class PrintCodeVisitor

java.lang.Object
  extended by org.objectweb.asm.util.PrintCodeVisitor
All Implemented Interfaces:
CodeVisitor
Direct Known Subclasses:
ASMifierCodeVisitor, TraceCodeVisitor

public abstract class PrintCodeVisitor
extends Object
implements CodeVisitor

An abstract code visitor that prints the code it visits. Each visitXXX method clears the buf buffer, calls the corresponding printXXX method, and then adds the buffer's content to the text list. In order to provide a concrete print code visitor, one must implement the printXXX methods in a sub class of this class. Each method should print the instructions it visits in buf.

Author:
Eric Bruneton, Eugene Kuleshov

Field Summary
protected  StringBuffer buf
          A buffer used to convert instructions to strings.
static String[] OPCODES
          The names of the Java Virtual Machine opcodes.
protected  List text
          The text to be printed.
 
Constructor Summary
protected PrintCodeVisitor()
          Constructs a new PrintCodeVisitor object.
 
Method Summary
 List getText()
          Returns the code printed by this code visitor.
abstract  void printAttribute(Attribute attr)
          Prints a non standard code attribute.
abstract  void printFieldInsn(int opcode, String owner, String name, String desc)
          Prints a field instruction.
abstract  void printIincInsn(int var, int increment)
          Prints an IINC instruction.
abstract  void printInsn(int opcode)
          Prints a zero operand instruction.
abstract  void printIntInsn(int opcode, int operand)
          Prints an instruction with a single int operand.
abstract  void printJumpInsn(int opcode, Label label)
          Prints a jump instruction.
abstract  void printLabel(Label label)
          Prints a label.
abstract  void printLdcInsn(Object cst)
          Prints a LDC instruction.
abstract  void printLineNumber(int line, Label start)
          Prints a line number declaration.
abstract  void printLocalVariable(String name, String desc, Label start, Label end, int index)
          Prints a local variable declaration.
abstract  void printLookupSwitchInsn(Label dflt, int[] keys, Label[] labels)
          Prints a LOOKUPSWITCH instruction.
abstract  void printMaxs(int maxStack, int maxLocals)
          Prints the maximum stack size and the maximum number of local variables of the method.
abstract  void printMethodInsn(int opcode, String owner, String name, String desc)
          Prints a method instruction.
abstract  void printMultiANewArrayInsn(String desc, int dims)
          Prints a MULTIANEWARRAY instruction.
abstract  void printTableSwitchInsn(int min, int max, Label dflt, Label[] labels)
          Prints a TABLESWITCH instruction.
abstract  void printTryCatchBlock(Label start, Label end, Label handler, String type)
          Prints a try catch block.
abstract  void printTypeInsn(int opcode, String desc)
          Prints a type instruction.
abstract  void printVarInsn(int opcode, int var)
          Prints a local variable instruction.
 void visitAttribute(Attribute attr)
          Visits a non standard attribute of the code.
 void visitFieldInsn(int opcode, String owner, String name, String desc)
          Visits a field instruction.
 void visitIincInsn(int var, int increment)
          Visits an IINC instruction.
 void visitInsn(int opcode)
          Visits a zero operand instruction.
 void visitIntInsn(int opcode, int operand)
          Visits an instruction with a single int operand.
 void visitJumpInsn(int opcode, Label label)
          Visits a jump instruction.
 void visitLabel(Label label)
          Visits a label.
 void visitLdcInsn(Object cst)
          Visits a LDC instruction.
 void visitLineNumber(int line, Label start)
          Visits a line number declaration.
 void visitLocalVariable(String name, String desc, Label start, Label end, int index)
          Visits a local variable declaration.
 void visitLookupSwitchInsn(Label dflt, int[] keys, Label[] labels)
          Visits a LOOKUPSWITCH instruction.
 void visitMaxs(int maxStack, int maxLocals)
          Visits the maximum stack size and the maximum number of local variables of the method.
 void visitMethodInsn(int opcode, String owner, String name, String desc)
          Visits a method instruction.
 void visitMultiANewArrayInsn(String desc, int dims)
          Visits a MULTIANEWARRAY instruction.
 void visitTableSwitchInsn(int min, int max, Label dflt, Label[] labels)
          Visits a TABLESWITCH instruction.
 void visitTryCatchBlock(Label start, Label end, Label handler, String type)
          Visits a try catch block.
 void visitTypeInsn(int opcode, String desc)
          Visits a type instruction.
 void visitVarInsn(int opcode, int var)
          Visits a local variable instruction.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

text

protected final List text
The text to be printed. See text.


buf

protected final StringBuffer buf
A buffer used to convert instructions to strings.


OPCODES

public static final String[] OPCODES
The names of the Java Virtual Machine opcodes.

Constructor Detail

PrintCodeVisitor

protected PrintCodeVisitor()
Constructs a new PrintCodeVisitor object.

Method Detail

visitInsn

public void visitInsn(int opcode)
Description copied from interface: CodeVisitor
Visits a zero operand instruction.

Specified by:
visitInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

visitIntInsn

public void visitIntInsn(int opcode,
                         int operand)
Description copied from interface: CodeVisitor
Visits an instruction with a single int operand.

Specified by:
visitIntInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the instruction to be visited. This opcode is either BIPUSH, SIPUSH or NEWARRAY.
operand - the operand of the instruction to be visited.

visitVarInsn

public void visitVarInsn(int opcode,
                         int var)
Description copied from interface: CodeVisitor
Visits a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.

Specified by:
visitVarInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the local variable instruction to be visited. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
var - the operand of the instruction to be visited. This operand is the index of a local variable.

visitTypeInsn

public void visitTypeInsn(int opcode,
                          String desc)
Description copied from interface: CodeVisitor
Visits a type instruction. A type instruction is an instruction that takes a type descriptor as parameter.

Specified by:
visitTypeInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
desc - the operand of the instruction to be visited. This operand is must be a fully qualified class name in internal form, or the type descriptor of an array type (see Type).

visitFieldInsn

public void visitFieldInsn(int opcode,
                           String owner,
                           String name,
                           String desc)
Description copied from interface: CodeVisitor
Visits a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.

Specified by:
visitFieldInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
owner - the internal name of the field's owner class (see getInternalName).
name - the field's name.
desc - the field's descriptor (see Type).

visitMethodInsn

public void visitMethodInsn(int opcode,
                            String owner,
                            String name,
                            String desc)
Description copied from interface: CodeVisitor
Visits a method instruction. A method instruction is an instruction that invokes a method.

Specified by:
visitMethodInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
owner - the internal name of the method's owner class (see getInternalName).
name - the method's name.
desc - the method's descriptor (see Type).

visitJumpInsn

public void visitJumpInsn(int opcode,
                          Label label)
Description copied from interface: CodeVisitor
Visits a jump instruction. A jump instruction is an instruction that may jump to another instruction.

Specified by:
visitJumpInsn in interface CodeVisitor
Parameters:
opcode - the opcode of the type instruction to be visited. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
label - the operand of the instruction to be visited. This operand is a label that designates the instruction to which the jump instruction may jump.

visitLabel

public void visitLabel(Label label)
Description copied from interface: CodeVisitor
Visits a label. A label designates the instruction that will be visited just after it.

Specified by:
visitLabel in interface CodeVisitor
Parameters:
label - a Label object.

visitLdcInsn

public void visitLdcInsn(Object cst)
Description copied from interface: CodeVisitor
Visits a LDC instruction.

Specified by:
visitLdcInsn in interface CodeVisitor
Parameters:
cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double a String (or a Type for .class constants, for classes whose version is 49.0 or more).

visitIincInsn

public void visitIincInsn(int var,
                          int increment)
Description copied from interface: CodeVisitor
Visits an IINC instruction.

Specified by:
visitIincInsn in interface CodeVisitor
Parameters:
var - index of the local variable to be incremented.
increment - amount to increment the local variable by.

visitTableSwitchInsn

public void visitTableSwitchInsn(int min,
                                 int max,
                                 Label dflt,
                                 Label[] labels)
Description copied from interface: CodeVisitor
Visits a TABLESWITCH instruction.

Specified by:
visitTableSwitchInsn in interface CodeVisitor
Parameters:
min - the minimum key value.
max - the maximum key value.
dflt - beginning of the default handler block.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

visitLookupSwitchInsn

public void visitLookupSwitchInsn(Label dflt,
                                  int[] keys,
                                  Label[] labels)
Description copied from interface: CodeVisitor
Visits a LOOKUPSWITCH instruction.

Specified by:
visitLookupSwitchInsn in interface CodeVisitor
Parameters:
dflt - beginning of the default handler block.
keys - the values of the keys.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

visitMultiANewArrayInsn

public void visitMultiANewArrayInsn(String desc,
                                    int dims)
Description copied from interface: CodeVisitor
Visits a MULTIANEWARRAY instruction.

Specified by:
visitMultiANewArrayInsn in interface CodeVisitor
Parameters:
desc - an array type descriptor (see Type).
dims - number of dimensions of the array to allocate.

visitTryCatchBlock

public void visitTryCatchBlock(Label start,
                               Label end,
                               Label handler,
                               String type)
Description copied from interface: CodeVisitor
Visits a try catch block.

Specified by:
visitTryCatchBlock in interface CodeVisitor
Parameters:
start - beginning of the exception handler's scope (inclusive).
end - end of the exception handler's scope (exclusive).
handler - beginning of the exception handler's code.
type - internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).

visitMaxs

public void visitMaxs(int maxStack,
                      int maxLocals)
Description copied from interface: CodeVisitor
Visits the maximum stack size and the maximum number of local variables of the method.

Specified by:
visitMaxs in interface CodeVisitor
Parameters:
maxStack - maximum stack size of the method.
maxLocals - maximum number of local variables for the method.

visitLocalVariable

public void visitLocalVariable(String name,
                               String desc,
                               Label start,
                               Label end,
                               int index)
Description copied from interface: CodeVisitor
Visits a local variable declaration.

Specified by:
visitLocalVariable in interface CodeVisitor
Parameters:
name - the name of a local variable.
desc - the type descriptor of this local variable.
start - the first instruction corresponding to the scope of this local variable (inclusive).
end - the last instruction corresponding to the scope of this local variable (exclusive).
index - the local variable's index.

visitLineNumber

public void visitLineNumber(int line,
                            Label start)
Description copied from interface: CodeVisitor
Visits a line number declaration.

Specified by:
visitLineNumber in interface CodeVisitor
Parameters:
line - a line number. This number refers to the source file from which the class was compiled.
start - the first instruction corresponding to this line number.

visitAttribute

public void visitAttribute(Attribute attr)
Description copied from interface: CodeVisitor
Visits a non standard attribute of the code. This method must visit only the first attribute in the given attribute list.

Specified by:
visitAttribute in interface CodeVisitor
Parameters:
attr - a non standard code attribute. Must not be null.

getText

public List getText()
Returns the code printed by this code visitor.

Returns:
the code printed by this code visitor. See text.

printInsn

public abstract void printInsn(int opcode)
Prints a zero operand instruction.

Parameters:
opcode - the opcode of the instruction to be printed. This opcode is either NOP, ACONST_NULL, ICONST_M1, ICONST_0, ICONST_1, ICONST_2, ICONST_3, ICONST_4, ICONST_5, LCONST_0, LCONST_1, FCONST_0, FCONST_1, FCONST_2, DCONST_0, DCONST_1, IALOAD, LALOAD, FALOAD, DALOAD, AALOAD, BALOAD, CALOAD, SALOAD, IASTORE, LASTORE, FASTORE, DASTORE, AASTORE, BASTORE, CASTORE, SASTORE, POP, POP2, DUP, DUP_X1, DUP_X2, DUP2, DUP2_X1, DUP2_X2, SWAP, IADD, LADD, FADD, DADD, ISUB, LSUB, FSUB, DSUB, IMUL, LMUL, FMUL, DMUL, IDIV, LDIV, FDIV, DDIV, IREM, LREM, FREM, DREM, INEG, LNEG, FNEG, DNEG, ISHL, LSHL, ISHR, LSHR, IUSHR, LUSHR, IAND, LAND, IOR, LOR, IXOR, LXOR, I2L, I2F, I2D, L2I, L2F, L2D, F2I, F2L, F2D, D2I, D2L, D2F, I2B, I2C, I2S, LCMP, FCMPL, FCMPG, DCMPL, DCMPG, IRETURN, LRETURN, FRETURN, DRETURN, ARETURN, RETURN, ARRAYLENGTH, ATHROW, MONITORENTER, or MONITOREXIT.

printIntInsn

public abstract void printIntInsn(int opcode,
                                  int operand)
Prints an instruction with a single int operand.

Parameters:
opcode - the opcode of the instruction to be printed. This opcode is either BIPUSH, SIPUSH or NEWARRAY.
operand - the operand of the instruction to be printed.

printVarInsn

public abstract void printVarInsn(int opcode,
                                  int var)
Prints a local variable instruction. A local variable instruction is an instruction that loads or stores the value of a local variable.

Parameters:
opcode - the opcode of the local variable instruction to be printed. This opcode is either ILOAD, LLOAD, FLOAD, DLOAD, ALOAD, ISTORE, LSTORE, FSTORE, DSTORE, ASTORE or RET.
var - the operand of the instruction to be printed. This operand is the index of a local variable.

printTypeInsn

public abstract void printTypeInsn(int opcode,
                                   String desc)
Prints a type instruction. A type instruction is an instruction that takes a type descriptor as parameter.

Parameters:
opcode - the opcode of the type instruction to be printed. This opcode is either NEW, ANEWARRAY, CHECKCAST or INSTANCEOF.
desc - the operand of the instruction to be printed. This operand is must be a fully qualified class name in internal form, or a the type descriptor of an array type (see Type).

printFieldInsn

public abstract void printFieldInsn(int opcode,
                                    String owner,
                                    String name,
                                    String desc)
Prints a field instruction. A field instruction is an instruction that loads or stores the value of a field of an object.

Parameters:
opcode - the opcode of the type instruction to be printed. This opcode is either GETSTATIC, PUTSTATIC, GETFIELD or PUTFIELD.
owner - the internal name of the field's owner class (see getInternalName).
name - the field's name.
desc - the field's descriptor (see Type).

printMethodInsn

public abstract void printMethodInsn(int opcode,
                                     String owner,
                                     String name,
                                     String desc)
Prints a method instruction. A method instruction is an instruction that invokes a method.

Parameters:
opcode - the opcode of the type instruction to be printed. This opcode is either INVOKEVIRTUAL, INVOKESPECIAL, INVOKESTATIC or INVOKEINTERFACE.
owner - the internal name of the method's owner class (see getInternalName).
name - the method's name.
desc - the method's descriptor (see Type).

printJumpInsn

public abstract void printJumpInsn(int opcode,
                                   Label label)
Prints a jump instruction. A jump instruction is an instruction that may jump to another instruction.

Parameters:
opcode - the opcode of the type instruction to be printed. This opcode is either IFEQ, IFNE, IFLT, IFGE, IFGT, IFLE, IF_ICMPEQ, IF_ICMPNE, IF_ICMPLT, IF_ICMPGE, IF_ICMPGT, IF_ICMPLE, IF_ACMPEQ, IF_ACMPNE, GOTO, JSR, IFNULL or IFNONNULL.
label - the operand of the instruction to be printed. This operand is a label that designates the instruction to which the jump instruction may jump.

printLabel

public abstract void printLabel(Label label)
Prints a label. A label designates the instruction that will be visited just after it.

Parameters:
label - a Label object.

printLdcInsn

public abstract void printLdcInsn(Object cst)
Prints a LDC instruction.

Parameters:
cst - the constant to be loaded on the stack. This parameter must be a non null Integer, a Float, a Long, a Double or a String.

printIincInsn

public abstract void printIincInsn(int var,
                                   int increment)
Prints an IINC instruction.

Parameters:
var - index of the local variable to be incremented.
increment - amount to increment the local variable by.

printTableSwitchInsn

public abstract void printTableSwitchInsn(int min,
                                          int max,
                                          Label dflt,
                                          Label[] labels)
Prints a TABLESWITCH instruction.

Parameters:
min - the minimum key value.
max - the maximum key value.
dflt - beginning of the default handler block.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the min + i key.

printLookupSwitchInsn

public abstract void printLookupSwitchInsn(Label dflt,
                                           int[] keys,
                                           Label[] labels)
Prints a LOOKUPSWITCH instruction.

Parameters:
dflt - beginning of the default handler block.
keys - the values of the keys.
labels - beginnings of the handler blocks. labels[i] is the beginning of the handler block for the keys[i] key.

printMultiANewArrayInsn

public abstract void printMultiANewArrayInsn(String desc,
                                             int dims)
Prints a MULTIANEWARRAY instruction.

Parameters:
desc - an array type descriptor (see Type).
dims - number of dimensions of the array to allocate.

printTryCatchBlock

public abstract void printTryCatchBlock(Label start,
                                        Label end,
                                        Label handler,
                                        String type)
Prints a try catch block.

Parameters:
start - beginning of the exception handler's scope (inclusive).
end - end of the exception handler's scope (exclusive).
handler - beginning of the exception handler's code.
type - internal name of the type of exceptions handled by the handler, or null to catch any exceptions (for "finally" blocks).

printMaxs

public abstract void printMaxs(int maxStack,
                               int maxLocals)
Prints the maximum stack size and the maximum number of local variables of the method.

Parameters:
maxStack - maximum stack size of the method.
maxLocals - maximum number of local variables for the method.

printLocalVariable

public abstract void printLocalVariable(String name,
                                        String desc,
                                        Label start,
                                        Label end,
                                        int index)
Prints a local variable declaration.

Parameters:
name - the name of a local variable.
desc - the type descriptor of this local variable.
start - the first instruction corresponding to the scope of this local variable (inclusive).
end - the last instruction corresponding to the scope of this local variable (exclusive).
index - the local variable's index.

printLineNumber

public abstract void printLineNumber(int line,
                                     Label start)
Prints a line number declaration.

Parameters:
line - a line number. This number refers to the source file from which the class was compiled.
start - the first instruction corresponding to this line number.

printAttribute

public abstract void printAttribute(Attribute attr)
Prints a non standard code attribute.

Parameters:
attr - a non standard code attribute.