Package com.tonic.analysis.execution.frame

Class CallStack

java.lang.Object

com.tonic.analysis.execution.frame.CallStack

public final class CallStack
extends Object

A bounded stack of interpreter frames with overflow and underflow checking.

Constructor Summary

Constructors

Constructor	Description
CallStack(int maxDepth)	Creates an empty call stack.

Method Summary

Modifier and Type	Method	Description
void	clear()	Removes all frames from the stack.
int	depth()
String	formatStackTrace()	Renders the stack as a multi-line trace with method, line, and PC per frame.
boolean	isEmpty()
StackFrame	peek()	Returns the top frame without removing it.
StackFrame	peekAt(int depth)	Returns the frame a given number of levels below the top without removing it.
StackFrame	pop()	Removes and returns the top frame.
void	push(StackFrame frame)	Pushes a frame onto the stack.
List<StackFrame>	snapshot()	Copies the current frames into an immutable list.
Iterable<StackFrame>	topToBottom()
String	toString()

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

CallStack

public CallStack(int maxDepth)

Creates an empty call stack.

Parameters:

maxDepth - maximum number of frames before overflow

Throws:

IllegalArgumentException - if maxDepth is not positive

Method Detail

push

public void push(StackFrame frame)

Pushes a frame onto the stack.

Parameters:

frame - the frame to push

Throws:

IllegalArgumentException - if the frame is null

StackOverflowError - if the stack is at maximum depth

pop

public StackFrame pop()

Removes and returns the top frame.

Returns:

the popped frame

Throws:

IllegalStateException - if the stack is empty

peek

public StackFrame peek()

Returns the top frame without removing it.

Returns:

the top frame

Throws:

IllegalStateException - if the stack is empty

peekAt

public StackFrame peekAt(int depth)

Returns the frame a given number of levels below the top without removing it.

Parameters:

depth - levels below the top, 0 being the top frame

Returns:

the frame at that depth

Throws:

IllegalArgumentException - if depth is negative

IndexOutOfBoundsException - if depth is beyond the current stack size

depth

public int depth()

Returns:

the number of frames on the stack

isEmpty

public boolean isEmpty()

Returns:

whether the stack has no frames

clear

public void clear()

Removes all frames from the stack.

snapshot

public List<StackFrame> snapshot()

Copies the current frames into an immutable list.

Returns:

the frames ordered bottom to top

topToBottom

public Iterable<StackFrame> topToBottom()

Returns:

the live frames iterated from top to bottom

formatStackTrace

public String formatStackTrace()

Renders the stack as a multi-line trace with method, line, and PC per frame.

Returns:

the formatted trace, or a placeholder when the stack is empty

toString

public String toString()

Overrides:

toString in class Object