/*
 * The Apache Software License, Version 1.1
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 * Copyright (c) 1999 The Apache Software Foundation.  All rights 
 * reserved.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
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 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer. 
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 *    notice, this list of conditions and the following disclaimer in
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 *    distribution.
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 * 3. The end-user documentation included with the redistribution, if
 *    any, must include the following acknowlegement:  
 *       "This product includes software developed by the 
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowlegement may appear in the software itself,
 *    if and wherever such third-party acknowlegements normally appear.
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 *    Foundation" must not be used to endorse or promote products derived
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 */ 

package org.apache.commons.el;

import javax.servlet.jsp.el.ELException;
import java.math.BigInteger;

/**
 *
 * <p>The implementation of the modulus operator
 * 
 * @author Nathan Abramson - Art Technology Group
 * @version $Change: 181177 $$DateTime: 2001/06/26 08:45:09 $$Author: luehe $
 **/

public class ModulusOperator
  extends BinaryOperator
{
  //-------------------------------------
  // Singleton
  //-------------------------------------

  public static final ModulusOperator SINGLETON =
    new ModulusOperator ();

  //-------------------------------------
  /**
   *
   * Constructor
   **/
  public ModulusOperator ()
  {
  }

  //-------------------------------------
  // Expression methods
  //-------------------------------------
  /**
   *
   * Returns the symbol representing the operator
   **/
  public String getOperatorSymbol ()
  {
    return "%";
  }

  //-------------------------------------
  /**
   *
   * Applies the operator to the given value
   **/
  public Object apply (Object pLeft,
		       Object pRight,
		       Logger pLogger)
    throws ELException
  {
    if (pLeft == null &&
	pRight == null) {
      if (pLogger.isLoggingWarning ()) {
	pLogger.logWarning
	  (Constants.ARITH_OP_NULL,
	   getOperatorSymbol ());
      }
      return PrimitiveObjects.getInteger (0);
    }

    if ((pLeft != null &&
	 (Coercions.isFloatingPointType (pLeft) ||
	  Coercions.isFloatingPointString (pLeft))) ||
      Coercions.isBigDecimal(pLeft) ||
	(pRight != null &&
	 (Coercions.isFloatingPointType (pRight) ||
	  Coercions.isFloatingPointString (pRight) ||
      Coercions.isBigDecimal(pRight)))) {
      double left =
	Coercions.coerceToPrimitiveNumber (pLeft, Double.class, pLogger).
	doubleValue ();
      double right =
	Coercions.coerceToPrimitiveNumber (pRight, Double.class, pLogger).
	doubleValue ();

      try {
	return PrimitiveObjects.getDouble (left % right);
      }
      catch (Exception exc) {
	if (pLogger.isLoggingError ()) {
	  pLogger.logError
	    (Constants.ARITH_ERROR,
	     getOperatorSymbol (),
	     "" + left,
	     "" + right);
	}
	return PrimitiveObjects.getInteger (0);
      }
    }
    else if (Coercions.isBigInteger(pLeft) || Coercions.isBigInteger(pRight)) {
        BigInteger left = (BigInteger)
             Coercions.coerceToPrimitiveNumber(pLeft, BigInteger.class, pLogger);
        BigInteger right = (BigInteger)
            Coercions.coerceToPrimitiveNumber(pRight, BigInteger.class, pLogger);

        try {
            return left.remainder(right);
        } catch (Exception exc) {
            if (pLogger.isLoggingError()) {
                pLogger.logError
                    (Constants.ARITH_ERROR,
                        getOperatorSymbol(),
                        "" + left,
                        "" + right);
            }
            return PrimitiveObjects.getInteger(0);
        }
    }
    else {
      long left =
	Coercions.coerceToPrimitiveNumber (pLeft, Long.class, pLogger).
	longValue ();
      long right =
	Coercions.coerceToPrimitiveNumber (pRight, Long.class, pLogger).
	longValue ();

      try {
	return PrimitiveObjects.getLong (left % right);
      }
      catch (Exception exc) {
	if (pLogger.isLoggingError ()) {
	  pLogger.logError
	    (Constants.ARITH_ERROR,
	     getOperatorSymbol (),
	     "" + left,
	     "" + right);
	}
	return PrimitiveObjects.getInteger (0);
      }
    }
  }

  //-------------------------------------
}