operators
Class PSShowpage

java.lang.Object
  operators.PSShowpage

All Implemented Interfaces:

PSObject, PSOperator, PSPathOperator

public class PSShowpage

extends java.lang.Object

implements PSPathOperator

Implements PSPathOperator interface.

Methods such as getOperatorToken() are inherited from PSPathOperator interface which are inherited from PSOperator. This concrete class is responsible for redrawing everything stored in the Graphics Stack.

Constructor Summary

PSShowpage()

Method Summary

void	action(PSStack s, PSPath p) Redraws everything found in the Graphics Stack.
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

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

Constructor Detail

PSShowpage

public PSShowpage()

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 "showpage".

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.

Showpage can occur any time even with an empty Graphics Stack (with no obvious result).

Precondition : A valid instance of PSStack is given.
Postcondition : A reply to the question whether the operator can perfom its defined behaviour.

Specified by:

isValid in interface PSOperator

Parameters:

s - A reference to an instance of PSStack.

Returns:

True if the operation can be executed, false otherwise.

Throws:

PSSyntaxException - The syntax of the token is wrong.

action

public void action(PSStack s,
                   PSPath p)

Redraws everything found in the Graphics Stack.

Showpage will be executed even if the Graphics Stack is empty.

Precondition : A valid Runtime Stack and Graphics Stack are given to method.
Postcondition : All the contents of the Graphics Stack are redrawn.

Specified by:

action in interface PSPathOperator

Parameters:

s - The Runtime Stack which serves no purpose here.

p - The Graphics Stack.