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/**
*
*/
package de.fhswf.in.inf.java1.aufgabe12;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
/**
* Uses Reflection API to get the method for calculation.
*
* @author $Author: $
* @version $Revision: $, $Date: $ UTC
*/
public class BinaryTemplate extends BinaryOperator
{
private Method operator;
/**
* Gets the operator function from the Math class.
*
* @param mathFunction
* The name of the operation.
*/
public BinaryTemplate(String mathFunction)
{
if (mathFunction == null)
{
throw new IllegalArgumentException("Operation can't be null.");
}
if (mathFunction.isEmpty())
{
throw new IllegalArgumentException("Operations can't be empty.");
}
try
{
operator = Math.class.getMethod(mathFunction, Double.TYPE,
Double.TYPE);
}
catch (NoSuchMethodException e)
{
throw new IllegalArgumentException("Not a valid Operator.", e);
}
catch (SecurityException e)
{
throw new IllegalArgumentException("Security violation.", e);
}
}
/*
* (non-Javadoc)
*
* @see de.fhswf.in.inf.java1.aufgabe12.UnaryOperator#eval(double)
*/
@Override
final double eval(double d1, double d2)
{
Object tmp = null;
try
{
tmp = operator.invoke(null, d1, d2);
}
catch (IllegalAccessException e)
{
throw new IllegalStateException("Can't access method.", e);
}
catch (IllegalArgumentException e)
{
throw new IllegalStateException(
"Argument for Math function is not double.", e);
}
catch (InvocationTargetException e)
{
if (e.getCause() instanceof IllegalArgumentException)
{
throw new IllegalArgumentException("Illegal Argument.", e);
}
throw new IllegalStateException("Unexpected exception.", e);
}
return (double) tmp;
}
}
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