/*
 ***************************************************************************************
 *  Copyright (C) 2006 EsperTech, Inc. All rights reserved.                            *
 *  http://www.espertech.com/esper                                                     *
 *  http://www.espertech.com                                                           *
 *  ---------------------------------------------------------------------------------- *
 *  The software in this package is published under the terms of the GPL license       *
 *  a copy of which has been included with this distribution in the license.txt file.  *
 ***************************************************************************************
 */
package com.espertech.esper.type;

import java.util.HashSet;
import java.util.Set;

/**
 * Encapsulates a parameter specifying a frequency, i.e. '* / 5'.
 */
public class FrequencyParameter implements NumberSetParameter {
    private int frequency;
    private static final long serialVersionUID = -2303214112045704231L;

    /**
     * Ctor.
     *
     * @param frequency - divisor specifying frequency
     */
    public FrequencyParameter(int frequency) {
        this.frequency = frequency;

        if (frequency <= 0) {
            throw new IllegalArgumentException("Zero or negative value supplied as freqeuncy");
        }
    }

    /**
     * Returns frequency.
     *
     * @return frequency divisor
     */
    public int getFrequency() {
        return frequency;
    }

    public boolean isWildcard(int min, int max) {
        if (frequency == 1) {
            return true;
        }
        return false;
    }

    public Set<Integer> getValuesInRange(int min, int max) {
        Set<Integer> values = new HashSet<Integer>();
        int start = min - min % frequency;

        do {
            if (start >= min) {
                values.add(start);
            }
            start += frequency;
        }
        while (start <= max);

        return values;
    }

    public boolean containsPoint(int point) {
        return point % frequency == 0;
    }

    public String formatted() {
        return "*/" + frequency;
    }
}