duration.java

《Java核心技术应用开发》电子工业出版社书籍源代码

/**
 *  这个类描述时间的长度。 它包括小时，分和秒
 *
 */
public class Duration implements java.io.Serializable {

	/**
	 *  小时数
	 */
	protected int hours;

	/**
	 *  分钟数
	 */
	protected int minutes;


	/**
	 *  秒数
	 */
	protected int seconds;

	/**
	 *  默认构造方法
	 */
	public Duration() {
		hours = 0;
		minutes = 0;
		seconds = 0;
	}

	/**
	 *  接受小时，分和秒三个参数的构造方法
	 */
	public Duration(int theHours, int theMinutes, int theSeconds) {
		hours = theHours;
		minutes = theMinutes;
		seconds = theSeconds;
	}

	/**
	 *  接受总秒数的构造方法
	 */
	public Duration(int totalSeconds) {
		hours = totalSeconds / 3600;
		int rem = totalSeconds - (hours * 3600);
		minutes = rem / 60;
		seconds = rem % 60;
	}

	/**
	 * 返回小时数
	 */
	public int getHours() {
		return hours;
	}
	
	/**
	 * 返回分钟数
	 */
	public int getMinutes() {
		return minutes;
	}
	
	/**
	 *  返回秒数
	 */
	public int getSeconds() {
		return seconds;
	}

	/**
	 *  返回总秒数
	 */
	public int getTotalSeconds() {
		return seconds + (60 * (minutes + (60 * hours)));
	}

	/**
	 *  长度求和
	 */
	public Duration add(Duration aDuration) {
		int total = getTotalSeconds() + aDuration.getTotalSeconds();
		return new Duration(total);
	}

	/**
	 *  长度求差
	 */
	public Duration subtract(Duration aDuration) {
		int diff = getTotalSeconds() - aDuration.getTotalSeconds();
		int total = Math.abs(diff);
		
		return new Duration(total);
	}


	/**
	 *  Duration对象的格式化:
	 *    hh:mm:ss
	 *
	 */
	public String toString() {
		String result = "";

		result = result + padLeadingZero(hours) + ":";
		
		result = result + padLeadingZero(minutes) + ":";
		
		result = result + padLeadingZero(seconds);
		
		return result;
	}

	/** 
	 *  如果数字小于10， 在数字左面加0  
	 *
	 *  例如:
	 *    0    ----->   "00"
	 *    7    ----->   "07"
	 *    14   ----->   "14"
	 */
	private String padLeadingZero(int number) {
	
		String result = "";
		
		if (number < 10) {
			result = "0"; 
		}

		result = result + Integer.toString(number);
		
		return result;
	}
	
}