sjm.imperative
Class ForCommand

java.lang.Object
  |
  +--sjm.imperative.Command
        |
        +--sjm.imperative.ForCommand

public class ForCommand

extends Command

This command mimics a normal "for" loop, such as:

     for (int i = 0; i < limit; i++){
         // body
     }
 

This class retains four parameters which the constructors receive or establish. These parameters are a setup command, a condition, an end command, and a body command.

The execute method executes a "for" loop, essentially executing:

     for (setup; condition; endCommand){
         bodyCommand;
     }
 

Field Summary

protected Command	bodyCommand
protected BooleanTerm	condition
protected Command	endCommand
protected Command	setupCommand

Constructor Summary

ForCommand(Command setupCommand, BooleanTerm condition, Command endCommand, Command bodyCommand)
Construct a "for" command from the given setup command, condition, endCommand, and bodyCommand.

ForCommand(Variable v, double from, double to, double step, Command bodyCommand)
Construct a "for" command that iterates the supplied variable over the doubles from the "from" parameter to the "to" parameter, stepping by the "step" parameter.

ForCommand(Variable v, int from, int to, Command bodyCommand)
Construct a "for" command that iterates the supplied variable over the integers from the "from" parameter to the "to" parameter.

Method Summary

void	execute() Execute this "for" command.
java.lang.String	toString() Returns a string description of this for command.

Methods inherited from class java.lang.Object

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

Field Detail

setupCommand

protected Command setupCommand

condition

protected BooleanTerm condition

endCommand

protected Command endCommand

bodyCommand

protected Command bodyCommand

Constructor Detail

ForCommand

public ForCommand(Variable v,
                  double from,
                  double to,
                  double step,
                  Command bodyCommand)

Construct a "for" command that iterates the supplied variable over the doubles from the "from" parameter to the "to" parameter, stepping by the "step" parameter. This command will iterate, adding step to the initial value, ceasing the loop when the value is greater than the "to" limit.

Parameters:

Variable - the variable to iterate

from - the initial value for the variable

to - a value not to exceed in the loop

step - the amount to increment by

Command - the command to repeatedly execute

ForCommand

public ForCommand(Variable v,
                  int from,
                  int to,
                  Command bodyCommand)

Construct a "for" command that iterates the supplied variable over the integers from the "from" parameter to the "to" parameter. For example, the following code segment prints out "my\n" five times.

 
     Variable i = new Variable("i");
     Fact f = new Fact("my");
     PrintCommand p = new PrintCommand(f); *     
     new ForCommand(i, 1, 5, p).execute();
 
 

Parameters:

Variable - the variable to iterate

int - the initial value for the variable

int - the final value for the variable

Command - the command to repeatedly execute

ForCommand

public ForCommand(Command setupCommand,
                  BooleanTerm condition,
                  Command endCommand,
                  Command bodyCommand)

Construct a "for" command from the given setup command, condition, endCommand, and bodyCommand.

Parameters:

setupCommand - the command to execute before the "for" loop begins

condition - the condition to check before executing the body

endCommand - the condition to check after executing the body

bodyCommand - the command to repeatedly execute

Method Detail

execute

public void execute()

Execute this "for" command. This means executing the setup command and then looping. The loop checks that the condition it true, executes the body command, and executes the end command.

Overrides:

execute in class Command

toString

public java.lang.String toString()

Returns a string description of this for command.

Overrides:

toString in class java.lang.Object

Returns:

a string description of this for command