Frame (Javassist API)

java.lang.Object
- javassist.bytecode.analysis.Frame

```
public class Frame
extends java.lang.Object
```
Represents the stack frame and local variable table at a particular point in time.

Author:

Jason T. Greene

Constructor Summary

Constructors
Constructor and Description

Frame(int locals, int stack)
Create a new frame with the specified local variable table size, and max stack size

Constructors
Constructor and Description
`Frame(int locals, int stack)` Create a new frame with the specified local variable table size, and max stack size

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`void`	`clearStack()` Empties the stack
`Frame`	`copy()` Makes a shallow copy of this frame, i.e.
`Frame`	`copyStack()` Makes a shallow copy of the stack portion of this frame.
`Type`	`getLocal(int index)` Returns the local varaible table entry at index.
`Type`	`getStack(int index)` Returns the type on the stack at the specified index.
`int`	`getTopIndex()` Gets the index of the type sitting at the top of the stack.
`int`	`localsLength()` Returns the number of local variable table entries, specified at construction.
`boolean`	`merge(Frame frame)` Merges all types on the stack and local variable table of this frame with that of the specified type.
`boolean`	`mergeStack(Frame frame)` Merges all types on the stack of this frame instance with that of the specified frame.
`Type`	`peek()` Gets the top of the stack without altering it
`Type`	`pop()` Alters the stack to contain one less element and return it.
`void`	`push(Type type)` Alters the stack by placing the passed type on the top
`void`	`setLocal(int index, Type type)` Sets the local variable table entry at index to a type.
`void`	`setStack(int index, Type type)` Sets the type of the stack position
`java.lang.String`	`toString()`

Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Constructor Detail
  - Frame
```
public Frame(int locals,
             int stack)
```
    Create a new frame with the specified local variable table size, and max stack size
    
    Parameters:
    
    locals - the number of local variable table entries
    
    stack - the maximum stack size
- Method Detail
  - getLocal
```
public Type getLocal(int index)
```
    Returns the local varaible table entry at index.
    
    Parameters:
    
    index - the position in the table
    
    Returns:
    
    the type if one exists, or null if the position is empty
  - setLocal
```
public void setLocal(int index,
                     Type type)
```
    Sets the local variable table entry at index to a type.
    
    Parameters:
    
    index - the position in the table
    
    type - the type to set at the position
  - getStack
```
public Type getStack(int index)
```
    Returns the type on the stack at the specified index.
    
    Parameters:
    
    index - the position on the stack
    
    Returns:
    
    the type of the stack position
  - setStack
```
public void setStack(int index,
                     Type type)
```
    Sets the type of the stack position
    
    Parameters:
    
    index - the position on the stack
    
    type - the type to set
  - clearStack
```
public void clearStack()
```
    Empties the stack
  - getTopIndex
```
public int getTopIndex()
```
    Gets the index of the type sitting at the top of the stack. This is not to be confused with a length operation which would return the number of elements, not the position of the last element.
    
    Returns:
    
    the position of the element at the top of the stack
  - localsLength
```
public int localsLength()
```
    Returns the number of local variable table entries, specified at construction.
    
    Returns:
    
    the number of local variable table entries
  - peek
```
public Type peek()
```
    Gets the top of the stack without altering it
    
    Returns:
    
    the top of the stack
  - pop
```
public Type pop()
```
    Alters the stack to contain one less element and return it.
    
    Returns:
    
    the element popped from the stack
  - push
```
public void push(Type type)
```
    Alters the stack by placing the passed type on the top
    
    Parameters:
    
    type - the type to add to the top
  - copy
```
public Frame copy()
```
    Makes a shallow copy of this frame, i.e. the type instances will remain the same.
    
    Returns:
    
    the shallow copy
  - copyStack
```
public Frame copyStack()
```
    Makes a shallow copy of the stack portion of this frame. The local variable table size will be copied, but its contents will be empty.
    
    Returns:
    
    the shallow copy of the stack
  - mergeStack
```
public boolean mergeStack(Frame frame)
```
    Merges all types on the stack of this frame instance with that of the specified frame. The local variable table is left untouched.
    
    Parameters:
    
    frame - the frame to merge the stack from
    
    Returns:
    
    true if any changes where made
  - merge
```
public boolean merge(Frame frame)
```
    Merges all types on the stack and local variable table of this frame with that of the specified type.
    
    Parameters:
    
    frame - the frame to merge with
    
    Returns:
    
    true if any changes to this frame where made by this merge
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object

Class Frame

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

Frame

Method Detail

getLocal

setLocal

getStack

setStack

clearStack

getTopIndex

localsLength

peek

pop

push

copy

copyStack

mergeStack

merge

toString