com.singularsys.extensions.statistical

Class ArgumentExpander

java.lang.Object

com.singularsys.extensions.statistical.ArgumentExpander

public abstract class ArgumentExpander
extends java.lang.Object

Base class for methods which expand Lists, arrays and other collections in their argument list. Subclasses can be used by PostfixMathCommands to expand their arguments.

The following pattern can be used which allows thread safe use.

 public class Sum extends PostfixMathCommand {
 class Processor extends ArgumentExpander {
        double total; // stores intermediate results

        @Override
        protected void doSingleArg(Object arg) throws EvaluationException {
            if(total==null)
                total= ((Double)arg).doubleValue();
            else {
                total += ((Double)arg).doubleValue();
            }
        }
  }

  public void run(Stack<Object> stack) throws EvaluationException {
        Processor p = new Processor();
        p.doStack(stack, this.curNumberOfParameters);
        stack.push(p.total);
  }
 }
 

Author:

Richard Morris

Constructor Summary

Constructors

Constructor and Description
ArgumentExpander()

Method Summary

Modifier and Type	Method and Description
void	doArg(java.lang.Object arg) Process an argument, arrays and Iterable objects are expanded.
protected abstract void	doSingleArg(java.lang.Object arg) Process an individual element after Lists/Arrays have been expanded.
void	doStack(java.util.Stack<java.lang.Object> stack, int neles) Pop neles elements off the stack and then call doArg on each.

Methods inherited from class java.lang.Object

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

Constructor Detail

ArgumentExpander

public ArgumentExpander()

Method Detail

doStack

public void doStack(java.util.Stack<java.lang.Object> stack,
                    int neles)
             throws EvaluationException

Pop neles elements off the stack and then call doArg on each.

Parameters:

stack -

neles - number of elements to pop

Throws:

EvaluationException

doArg

public void doArg(java.lang.Object arg)
           throws EvaluationException

Process an argument, arrays and Iterable objects are expanded. doSingleArg is called for each array element and each member of an iterable. If the argument is not an array/iterable doSingleArg is called on the argument.

Parameters:

arg -

Throws:

EvaluationException

doSingleArg

protected abstract void doSingleArg(java.lang.Object arg)
                             throws EvaluationException

Process an individual element after Lists/Arrays have been expanded.

Parameters:

arg -

Throws:

EvaluationException