operators
Class PSPstack

java.lang.Object
  operators.PSPstack

All Implemented Interfaces:

PSConsoleOperator, PSObject, PSOperator

public class PSPstack

extends java.lang.Object

implements PSConsoleOperator

Constructor Summary

PSPstack()

Method Summary

void	action(PSStack s, java.io.OutputStream os) Prints of the toppest value in the output plus i'ts removal.
java.lang.String	getOperatorToken() Returns the token identifying this operator.
boolean	isValid(PSStack s) Checks if it valid to use this operator now.

Methods inherited from class java.lang.Object

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

Constructor Detail

PSPstack

public PSPstack()

Method Detail

getOperatorToken

public java.lang.String getOperatorToken()

Returns the token identifying this operator.

Returns the name of the operand that this concrete class simulates,here "pstack".

Precondition : A valid operator class has been created.
Postcondition : A string is returned,labeling the semantics of this class.

Specified by:

getOperatorToken in interface PSOperator

Returns:

The token identifying this operator.

isValid

public boolean isValid(PSStack s)
                throws PSSyntaxException

Checks if it valid to use this operator now.

Prints the contents of the stack in the output.

Precondition : At least one element must be inside the stack.
Postcondition : A reply to whether the elements of the stack can printed.

Specified by:

isValid in interface PSOperator

Parameters:

s - A reference to a PSStack instance.

Returns:

True if the operation can be performed,false otherwise.

Throws:

PSSyntaxException - The syntax of the token is wrong.

action

public void action(PSStack s,
                   java.io.OutputStream os)

Prints of the toppest value in the output plus i'ts removal.

Precondition : At least one element must be inside the stack.
Postcondition : Printing all the elements of the stack.

Specified by:

action in interface PSConsoleOperator

Parameters:

s - The Run-time Stack where the elements are stored.

os - The stream where the output will be directed.