/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.taglibs.standard.lang.jstl;

/**
 * <p>The implementation of the modulus operator
 *
 * @author Nathan Abramson - Art Technology Group
 */

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,
                        Object pContext,
                        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))) ||
                (pRight != null &&
                        (Coercions.isFloatingPointType(pRight) ||
                                Coercions.isFloatingPointString(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 {
            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);
            }
        }
    }

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