package org.apache.commons.lang;

/* ====================================================================
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/**
 * {@link Number} オブジェクトの範囲を示します。
 * {@primary Represents a range of {@link Number} objects.}
 *
 * @author <a href="mailto:chrise@esha.com">Christopher Elkins</a>
 * @author <a href="mailto:scolebourne@joda.org">Stephen Colebourne</a>
 * @translator 日置 聡
 * @status firstdraft
 * @update 2003/08/12
 * @version $Revision: 1.1.1.1 $ $Date: 2004/02/13 10:02:04 $
 */
public final class NumberRange {


    /* The minimum number in this range. */
    private final Number min;

    /* The maximum number in this range. */
    private final Number max;


    /**
     * 指定された数値を範囲の最大値、最小値に設定し、新しいインスタンスを生成します。
     * {@primary Constructs a new instance using the specified number as both the
     * minimum and maximum in theis range.}
     *
     * @param num この範囲で使用される数値
     * {@primary the number to use for this range}
     * @throws NullPointerException number が <code>null</code> だった場合
     * {@primary if the number is <code>null</code>}
     */
    public NumberRange(Number num) {
        if (num == null) {
            throw new NullPointerException("num cannot be null");
        }

        this.min = num;
        this.max = num;
    }

    /**
     * 指定された最小値、最大値を持つ新しいインスタンスを生成します。
     * {@primary Constructs a new instance with the specified minimum and maximum
     * numbers.}
     *
     * @param min この範囲の最小値
     * {@primary the minimum number in this range}
     * @param max この範囲の最大値
     * {@primary the maximum number in this range}
     * @throws NullPointerException minimum または maximum のどちらかが <code>null</code> だった場合
     * {@primary if either the minimum or maximum number is <code>null</code>}
     */
    public NumberRange(Number min, Number max) {
        if (min == null) {
            throw new NullPointerException("min cannot be null");
        } else if (max == null) {
            throw new NullPointerException("max cannot be null");
        }

        if (max.doubleValue() < min.doubleValue()) {
            this.min = this.max = min;
        } else {
            this.min = min;
            this.max = max;
        }
    }

    /**
     * この範囲の最小値を返します。
     * {@primary Returns the minimum number in this range.}
     *
     * @return この範囲の最小値
     * {@primary the minimum number in this range}
     */
    public Number getMinimum() {
        return min;
    }

    /**
     * この範囲の最大値を返します。
     * {@primary Returns the maximum number in this range.}
     *
     * @return この範囲の最大値
     * {@primary the maximum number in this range}
     */
    public Number getMaximum() {
        return max;
    }

    /**
     * 指定された数値がこの範囲内であるかを評価します。
     * {@primary Tests whether the specified number occurs within this range.}
     *
     * @param number 評価対象となる数値
     * {@primary the number to test}
     * @return 指定された数値がこの範囲内である場合 <code>true</code> 、
     *         そうでない場合には <code>false</code>
     * {@primary <code>true</code> if the specified number occurs within this
     *           range; otherwise, <code>false</code>}
     */
    public boolean includesNumber(Number number) {
        if (number == null) {
            return false;
        } else {
            return !(min.doubleValue() > number.doubleValue()) &&
                !(max.doubleValue() < number.doubleValue());
        }
    }

    /**
     * 指定された範囲がこの範囲内であるかを評価します。
     * {@primary Tests whether the specified range occurs entirely within this range.}
     *
     * @param range 評価対象となる範囲
     * {@primary the range to test}
     * @return 指定された範囲がこの範囲内である場合 <code>true</code> 、
     *         そうでない場合には <code>false</code>
     * {@primary <code>true</code> if the specified range occurs entirely within
     *           this range; otherwise, <code>false</code>}
     */
    public boolean includesRange(NumberRange range) {
        if (range == null) {
            return false;
        } else {
            return includesNumber(range.min) && includesNumber(range.max);
        }
    }

    /**
     * 指定された範囲がこの範囲と重なる部分があるかを評価します。
     * {@primary Tests whether the specified range overlaps with this range.}
     *
     * @param range 評価対象となる範囲
     * {@primary the range to test}
     * @return 指定された範囲と重なる場合 <code>true</code> 、
     *         そうでない場合には <code>false</code>
     * {@primary <code>true</code> if the specified range overlaps with this
     *         range; otherwise, <code>false</code>}
     */
    public boolean overlaps(NumberRange range) {
        if (range == null) {
            return false;
        } else {
            return range.includesNumber(min) || range.includesNumber(max) || 
                includesRange(range);
        }
    }

    /**
     * このオブジェクトと他のオブジェクトが等しいかどうかを示します。 
     * {@primary Indicates whether some other object is "equal" to this one.}
     *
     * @param obj 比較対象の参照オブジェクト
     * {@primary the reference object with which to compare}
     * @return 引数に指定されたオブジェクトとこのオブジェクトが等しい場合 <code>true</code> 、
     *         そうでない場合には <code>false</code>
     * {@primary <code>true</code> if this object is the same as the obj
     *           argument; <code>false</code> otherwise}
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        } else if (!(obj instanceof NumberRange)) {
            return false;
        } else {
            NumberRange range = (NumberRange)obj;
            return min.equals(range.min) && max.equals(range.max);
        }
    }

    /**
     * このオブジェクトのハッシュコードの値を返します。
     * {@primary Returns a hash code value for this object.}
     *
     * @return このオブジェクトのハッシュコードの値
     * {@primary a hash code value for this object}
     */
    public int hashCode() {
        int result = 17;
        result = 37 * result + min.hashCode();
        result = 37 * result + max.hashCode();
        return result;
    }

    /**
     * この範囲の文字列表現を返します。 This string is the
     * この文字列は最小値と最大値をハイフン('-')で区切る形式となります。
     * その数値がマイナスの場合、括弧で括って表示します。
     * {@primary Returns the string representation of this range. This string is the
     * string representation of the minimum and maximum numbers in the range,
     * separated by a hyphen. If a number is negative, then it is enclosed
     * in parentheses.}
     *
     * @return この範囲の文字列表現
     * {@primary the string representation of this range}
     */
    public String toString() {
        StringBuffer sb = new StringBuffer();

        if (min.intValue() < 0) {
            sb.append('(')
                .append(min)
                .append(')');
        } else {
            sb.append(min);
        }

        sb.append('-');

        if (max.intValue() < 0) {
            sb.append('(')
                .append(max)
                .append(')');
        } else {
            sb.append(max);
        }

        return sb.toString();
    }

}