java.lang.Object
- org.apache.bcel.generic.Instruction

All Implemented Interfaces:

Cloneable

Direct Known Subclasses:

ACONST_NULL, ArithmeticInstruction, ArrayInstruction, ARRAYLENGTH, ATHROW, BIPUSH, BranchInstruction, BREAKPOINT, ConversionInstruction, CPInstruction, DCMPG, DCMPL, DCONST, FCMPG, FCMPL, FCONST, ICONST, IMPDEP1, IMPDEP2, LCMP, LCONST, LocalVariableInstruction, MONITORENTER, MONITOREXIT, NEWARRAY, NOP, RET, ReturnInstruction, SIPUSH, StackInstruction
```
public abstract class Instruction
extends Object
implements Cloneable
```
Abstract super class for all Java byte codes.

Field Summary

Fields
Modifier and Type	Field	Description
`protected short`	`length`	Deprecated. (since 6.0) will be made private; do not access directly, use getter/setter
`protected short`	`opcode`	Deprecated. (since 6.0) will be made private; do not access directly, use getter/setter

Constructor Summary

Constructors
Constructor Description

Instruction(short opcode, short length)

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Concrete Methods Deprecated Methods
Modifier and Type	Method	Description
`abstract void`	`accept(Visitor v)`	Call corresponding visitor method(s).
`int`	`consumeStack(ConstantPoolGen cpg)`	This method also gives right results for instructions whose effect on the stack depends on the constant pool entry they reference.
`Instruction`	`copy()`	Use with caution, since `BranchInstruction's have a `target' reference which is not copied correctly (only basic types are).
`void`	`dump(DataOutputStream out)`	Dump instruction as byte code to stream out.
`boolean`	`equals(Object that)`	Check for equality, delegated to comparator
`static InstructionComparator`	`getComparator()`	Deprecated. (6.0) use the built in comparator, or wrap this class in another object that implements these methods
`int`	`getLength()`
`String`	`getName()`
`short`	`getOpcode()`
`int`	`hashCode()`	calculate the hashCode of this object
`protected void`	`initFromFile(ByteSequence bytes, boolean wide)`	Read needed data (e.g.
`static boolean`	`isValidByte(int value)`	Check if the value can fit in a byte (signed)
`static boolean`	`isValidShort(int value)`	Check if the value can fit in a short (signed)
`int`	`produceStack(ConstantPoolGen cpg)`	This method also gives right results for instructions whose effect on the stack depends on the constant pool entry they reference.
`static Instruction`	`readInstruction(ByteSequence bytes)`	Read an instruction from (byte code) input stream and return the appropiate object.
`static void`	`setComparator(InstructionComparator c)`	Deprecated. (6.0) use the built in comparator, or wrap this class in another object that implements these methods
`String`	`toString()`
`String`	`toString(boolean verbose)`	Long output format: <name of opcode> "["<opcode number>"]" "("<length of instruction>")"
`String`	`toString(ConstantPool cp)`

Methods inherited from class java.lang.Object
clone, finalize, getClass, notify, notifyAll, wait, wait, wait

- Field Detail
  - length
```
@Deprecated
protected short length
```
    Deprecated.
    (since 6.0) will be made private; do not access directly, use getter/setter
  - opcode
```
@Deprecated
protected short opcode
```
    Deprecated.
    (since 6.0) will be made private; do not access directly, use getter/setter
- Constructor Detail
  - Instruction
```
public Instruction(short opcode,
                   short length)
```
- Method Detail
  - dump
```
public void dump(DataOutputStream out)
          throws IOException
```
    Dump instruction as byte code to stream out.
    
    Parameters:
    
    out - Output stream
    
    Throws:
    
    IOException
  - getName
```
public String getName()
```
    Returns:
    
    name of instruction, i.e., opcode name
  - toString
```
public String toString(boolean verbose)
```
    Long output format: <name of opcode> "["<opcode number>"]" "("<length of instruction>")"
    
    Parameters:
    
    verbose - long/short format switch
    
    Returns:
    
    mnemonic for instruction
  - toString
```
public String toString()
```
    Overrides:
    
    toString in class Object
    
    Returns:
    
    mnemonic for instruction in verbose format
  - toString
```
public String toString(ConstantPool cp)
```
    Returns:
    
    mnemonic for instruction with sumbolic references resolved
  - copy
```
public Instruction copy()
```
    Use with caution, since `BranchInstruction's have a `target' reference which is not copied correctly (only basic types are). This also applies for `Select' instructions with their multiple branch targets.
    
    Returns:
    
    (shallow) copy of an instruction
    
    See Also:
    
    BranchInstruction
  - initFromFile
```
protected void initFromFile(ByteSequence bytes,
                            boolean wide)
                     throws IOException
```
    Read needed data (e.g. index) from file.
    
    Parameters:
    
    bytes - byte sequence to read from
    
    wide - "wide" instruction flag
    
    Throws:
    
    IOException - may be thrown if the implementation needs to read data from the file
  - readInstruction
```
public static Instruction readInstruction(ByteSequence bytes)
                                   throws IOException
```
    Read an instruction from (byte code) input stream and return the appropiate object.
    If the Instruction is defined in InstructionConst, then the singleton instance is returned.
    
    Parameters:
    
    bytes - input stream bytes
    
    Returns:
    
    instruction object being read
    
    Throws:
    
    IOException
    
    See Also:
    
    InstructionConst.getInstruction(int)
  - consumeStack
```
public int consumeStack(ConstantPoolGen cpg)
```
    This method also gives right results for instructions whose effect on the stack depends on the constant pool entry they reference.
    
    Returns:
    
    Number of words consumed from stack by this instruction, or Constants.UNPREDICTABLE, if this can not be computed statically
  - produceStack
```
public int produceStack(ConstantPoolGen cpg)
```
    This method also gives right results for instructions whose effect on the stack depends on the constant pool entry they reference.
    
    Returns:
    
    Number of words produced onto stack by this instruction, or Constants.UNPREDICTABLE, if this can not be computed statically
  - getOpcode
```
public short getOpcode()
```
    Returns:
    
    this instructions opcode
  - getLength
```
public int getLength()
```
    Returns:
    
    length (in bytes) of instruction
  - accept
```
public abstract void accept(Visitor v)
```
    Call corresponding visitor method(s). The order is: Call visitor methods of implemented interfaces first, then call methods according to the class hierarchy in descending order, i.e., the most specific visitXXX() call comes last.
    
    Parameters:
    
    v - Visitor object
  - getComparator
```
@Deprecated
public static InstructionComparator getComparator()
```
    Deprecated.
    (6.0) use the built in comparator, or wrap this class in another object that implements these methods
    
    Get Comparator object used in the equals() method to determine equality of instructions.
    
    Returns:
    
    currently used comparator for equals()
  - setComparator
```
@Deprecated
public static void setComparator(InstructionComparator c)
```
    Deprecated.
    (6.0) use the built in comparator, or wrap this class in another object that implements these methods
    
    Set comparator to be used for equals().
  - equals
```
public boolean equals(Object that)
```
    Check for equality, delegated to comparator
    
    Overrides:
    
    equals in class Object
    
    Returns:
    
    true if that is an Instruction and has the same opcode
  - hashCode
```
public int hashCode()
```
    calculate the hashCode of this object
    
    Overrides:
    
    hashCode in class Object
    
    Returns:
    
    the hashCode
    
    Since:
    
    6.0
  - isValidByte
```
public static boolean isValidByte(int value)
```
    Check if the value can fit in a byte (signed)
    
    Parameters:
    
    value - the value to check
    
    Returns:
    
    true if the value is in range
    
    Since:
    
    6.0
  - isValidShort
```
public static boolean isValidShort(int value)
```
    Check if the value can fit in a short (signed)
    
    Parameters:
    
    value - the value to check
    
    Returns:
    
    true if the value is in range
    
    Since:
    
    6.0

Class Instruction

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

length

opcode

Constructor Detail

Instruction

Method Detail

dump

getName

toString

toString

toString

copy

initFromFile

readInstruction

consumeStack

produceStack

getOpcode

getLength

accept

getComparator

setComparator

equals

hashCode

isValidByte

isValidShort