org.problets.domain.model.variable
Class PtrModel

java.lang.Object
  org.problets.domain.model.DomainModel
      org.problets.domain.model.variable.AbstractVarModel
          org.problets.domain.model.variable.AccessVarModel
              org.problets.domain.model.variable.PtrModel

All Implemented Interfaces:

java.lang.Cloneable

public class PtrModel
extends AccessVarModel
implements java.lang.Cloneable

Model for a pointer variable

Author:

Amruth Kumar

Field Summary

static int	IDENTITY
static java.lang.String	NOT_DECLARED
static java.lang.String	NOT_INITIALIZED
static java.lang.String	OUT_OF_SCOPE
static java.lang.String	POINTEE_DEALLOCATED
static java.lang.String	POINTEE_OUT_OF_SCOPE

Fields inherited from class org.problets.domain.model.DomainModel

BOOLEAN, BREAKPOINT, CHARACTER, DOUBLE_PRECISION_REAL, ERROR_TYPE, EVAL_STATUS, expACTION, expASSIGNMENT, expAUTO_DEALLOCATION, expCALL, expCONDITION, expDECLARATION, expDEREFERENCING, expDYNAMIC_ALLOCATION, expDYNAMIC_ALLOCATION_INITIALIZATION, expDYNAMIC_DEALLOCATION, expELSE_CLAUSE, expERROR, expEXECUTION, expIF_CLAUSE, expINITIALIZATION, expINPUT, expPARAMETER_PASSING, expPRINT, expQUESTIONABLE, expREFERENCING, expRETURN, expRUNTIME_ERROR, expSEMANTIC_ERROR, expSYNTAX_ERROR, expUPDATE, MAX_OBJECT_IDENTITY, MIN_OBJECT_IDENTITY, QUADRUPLE_PRECISION_REAL, RUNTIME_ERROR, SEMANTIC_ERROR, SIGNED_INTEGER, SIGNED_LONG, SIGNED_SHORT, SINGLE_PRECISION_REAL, SYNTAX_ERROR, UNDEFINED_TYPE, UNSIGNED_INTEGER, UNSIGNED_LONG, UNSIGNED_SHORT, WARNING

Constructor Summary

PtrModel(int index, java.lang.String inputType)
We look for variables in the correct ordinality in symbolTable

PtrModel(java.lang.String inName, java.lang.String inputType)
Constructor used by Expression to create a pointer of a given name when creating a static expression for printing purposes

Method Summary

void	addToAssignees(java.lang.String template, ActivationRecord activationRecord) Handles generating code for the following cases: Address of a variable assigned to a pointer Dynamic allocation to a pointer with no value/initialization value/array An expression to a pointer Since we do not assign to pointers at code generation time, we cannot say to which variable the pointer points.
java.lang.Object	clone() Returns a clone of this object, and provides the basis for cloning of derived classes
void	explainObject(StackModel stack, HeapModel heap, Behavior behavior, java.lang.String statement, int event, int lineNumber, boolean abbreviated) -----------------------------------------------------
void	explainProcess(RunEnv runEnv, Behavior behavior, java.lang.String statement, int event, int lineNumber) For each step (e.g., print), If the step has been properly set up, (e.g., pointer points to a var which is initialized) Gives the full-fledged explanation Else, (e.g., pointer is not yet assigned, is out of scope, not yet declared, etc.) Gives an "Attempt was made" explanation
Scope	getAssignScope() Returns a reference to the scope where the pointer was assigned
void	getCode(java.util.Vector codeText, java.lang.String codeType, java.lang.String template, int lineNumber) Assembles the code for the pointer that fits the occasion in the Vector passed as a parameter
boolean	getDynamicallyAllocated() Returns whether this pointer was dynamically allocated
java.lang.Object	getLValue() Returns a reference to the object to which the pointer points
java.lang.String[]	getPossibleErrors() Returns the possible errors for pointers May want to post-process based on Student Model
Value	getValue() Returns the DEreferenced value of the pointer
static void	main(java.lang.String[] args) -----------------------------------------------------
void	print() -----------------------------------------------------
void	resetDynamicallyAllocated() Resets that the pointer was dynamically allocated
void	resetFlags() Resets the flags for the pointer variable
void	resetValue() Sets pointer to null
void	setDeclared() Sets the pointer to declared
void	setDynamicallyAllocated() Sets that the pointer was dynamically allocated
void	setValue(AbstractVarModel in_value, Scope in_scope) Sets the value of the pointer - value may be either a VarModel or AnonVarModel object - hence AbstractVarModel parameter
void	setValue(java.lang.Object inValue) Used by Assignment Expression

Methods inherited from class org.problets.domain.model.variable.AccessVarModel

getAssignees

Methods inherited from class org.problets.domain.model.variable.AbstractVarModel

getAllocated, getAssigned, getDeclared, getMetaDataType, getName, getType, getValueDifference, resetAllocated, resetDeclared, setAllocated

Methods inherited from class org.problets.domain.model.DomainModel

getId, getIdName, grade

Methods inherited from class java.lang.Object

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

Field Detail

IDENTITY

public static final int IDENTITY

See Also:

Constant Field Values

NOT_DECLARED

public static final java.lang.String NOT_DECLARED

See Also:

Constant Field Values

OUT_OF_SCOPE

public static final java.lang.String OUT_OF_SCOPE

See Also:

Constant Field Values

NOT_INITIALIZED

public static final java.lang.String NOT_INITIALIZED

See Also:

Constant Field Values

POINTEE_DEALLOCATED

public static final java.lang.String POINTEE_DEALLOCATED

See Also:

Constant Field Values

POINTEE_OUT_OF_SCOPE

public static final java.lang.String POINTEE_OUT_OF_SCOPE

See Also:

Constant Field Values

Constructor Detail

PtrModel

public PtrModel(int index,
                java.lang.String inputType)

We look for variables in the correct ordinality in symbolTable

Parameters:

-

PtrModel

public PtrModel(java.lang.String inName,
                java.lang.String inputType)

Constructor used by Expression to create a pointer of a given name when creating a static expression for printing purposes

Method Detail

clone

public java.lang.Object clone()

Description copied from class: DomainModel

Returns a clone of this object, and provides the basis for cloning of derived classes

Overrides:

clone in class AbstractVarModel

getValue

public Value getValue()

Returns the DEreferenced value of the pointer

Overrides:

getValue in class AbstractVarModel

Parameters:

-

Returns:

getLValue

public java.lang.Object getLValue()

Returns a reference to the object to which the pointer points

Parameters:

-

Returns:

getAssignScope

public Scope getAssignScope()

Returns a reference to the scope where the pointer was assigned

Parameters:

-

Returns:

getDynamicallyAllocated

public boolean getDynamicallyAllocated()

Returns whether this pointer was dynamically allocated

Parameters:

-

Returns:

resetFlags

public void resetFlags()

Resets the flags for the pointer variable

Overrides:

resetFlags in class AbstractVarModel

Parameters:

-

setDeclared

public void setDeclared()

Sets the pointer to declared

Overrides:

setDeclared in class AbstractVarModel

Parameters:

none -

setValue

public void setValue(AbstractVarModel in_value,
                     Scope in_scope)

Sets the value of the pointer - value may be either a VarModel or AnonVarModel object - hence AbstractVarModel parameter

Parameters:

-

setValue

public void setValue(java.lang.Object inValue)

Description copied from class: AbstractVarModel

Used by Assignment Expression

Overrides:

setValue in class AbstractVarModel

resetValue

public void resetValue()

Sets pointer to null

Parameters:

-

setDynamicallyAllocated

public void setDynamicallyAllocated()

Sets that the pointer was dynamically allocated

Parameters:

-

resetDynamicallyAllocated

public void resetDynamicallyAllocated()

Resets that the pointer was dynamically allocated

Parameters:

-

addToAssignees

public void addToAssignees(java.lang.String template,
                           ActivationRecord activationRecord)

Handles generating code for the following cases: Address of a variable assigned to a pointer Dynamic allocation to a pointer with no value/initialization value/array An expression to a pointer Since we do not assign to pointers at code generation time, we cannot say to which variable the pointer points. Since the following is possible; int * ptr = & count; while( true ) { cout << *ptr; // What pointee object should be included here? ptr = & index; } we cannot figure out in getCode() all the variables to which a pointer points. Instead, we will do this in the constructor, i.e., every time a pointer is initialized/ assigned, we add the variable/anonymous variable assigned to the pointer to an assigneeVector. During getCode(), for statements printing pointer variables, we will add all the elements in assigneeVector to codeLineObjects.

Overrides:

addToAssignees in class AccessVarModel

getCode

public void getCode(java.util.Vector codeText,
                    java.lang.String codeType,
                    java.lang.String template,
                    int lineNumber)

Assembles the code for the pointer that fits the occasion in the Vector passed as a parameter

Specified by:

getCode in class AbstractVarModel

Parameters:

-

getPossibleErrors

public java.lang.String[] getPossibleErrors()

Returns the possible errors for pointers May want to post-process based on Student Model

Specified by:

getPossibleErrors in class AbstractVarModel

explainProcess

public void explainProcess(RunEnv runEnv,
                           Behavior behavior,
                           java.lang.String statement,
                           int event,
                           int lineNumber)

For each step (e.g., print), If the step has been properly set up, (e.g., pointer points to a var which is initialized) Gives the full-fledged explanation Else, (e.g., pointer is not yet assigned, is out of scope, not yet declared, etc.) Gives an "Attempt was made" explanation

Specified by:

explainProcess in class AbstractVarModel

Parameters:

-

explainObject

public void explainObject(StackModel stack,
                          HeapModel heap,
                          Behavior behavior,
                          java.lang.String statement,
                          int event,
                          int lineNumber,
                          boolean abbreviated)

-----------------------------------------------------

Specified by:

explainObject in class AbstractVarModel

Parameters:

-

main

public static void main(java.lang.String[] args)

-----------------------------------------------------

Parameters:

-

print

public void print()

-----------------------------------------------------

Specified by:

print in class AbstractVarModel

Parameters:

-