【ThinkingInJava】44、数据生成器

<pre name="code" class="java">//: net/mindview/util/Generator.java// A generic interface.package net.mindview.util;public interface Generator<T> { T next(); } ///:~

/*** 书本:《Thinking In Java》* 功能:数据生成器--策略设计模式* 文件:CountingGenerator.java* 时间:2015年4月29日19:05:09* 作者:cutter_point*/package net.mindview.util;public class CountingGenerator{//一个布尔值的静态类public static class Boolean implements Generator<java.lang.Boolean>{private boolean value = false;@Overridepublic java.lang.Boolean next(){//返回一个和value相反的值value = !value;return value;}}//字节类型的静态类public static class Byte implements Generator<java.lang.Byte>{private byte value = 0;@Overridepublic java.lang.Byte next(){//下一个就是加一位,并返回前面那个值return value++;}}//静态的字符数组包含所有的字母static char[] chars = ("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ").toCharArray();//字符型的public static class Character implements Generator<java.lang.Character>{int index = -1;//索引@Override//得到一串字符里面的public java.lang.Character next(){index = (index + 1)%chars.length;//看看下一个字符在所有的字母里面的第几位return chars[index];}}//字符串类型public static class String implements Generator<java.lang.String>{private int length = 7;Generator<java.lang.Character> cg = new Character();public String() {}public String(int length) { this.length = length; }public java.lang.String next(){char[] buf = new char[length];for(int i = 0; i < length; ++i){buf[i] = cg.next();}return new java.lang.String(buf);}}//short类型的数据public static class Short implements Generator<java.lang.Short>{private short value = 0;@Overridepublic java.lang.Short next(){return value++;}}public static class Integer implements Generator<java.lang.Integer>{private int value = 0;@Overridepublic java.lang.Integer next(){return value++;}}public static class Float implements Generator<java.lang.Float> {    private float value = 0;    public java.lang.Float next()     {      float result = value;      value += 1.0;      return result;    }}public static class Double implements Generator<java.lang.Double>{private double value = 0.0;public java.lang.Double next(){double result = value;value += 1.0;return result;}}//public static void main(java.lang.String[] args)//{//Byte b = new Byte();//int i = b.next();//System.out.println(i);////System.out.println(new Character().next());////String s = new String(9);////System.out.println(s.next());//}}

/*** 书本:《Thinking In Java》* 功能:数据生成器--策略设计模式--测试类* 文件:CountingGenerator.java* 时间:2015年4月29日19:05:09* 作者:cutter_point*/package Lesson16Arrays;import net.mindview.util.CountingGenerator;import net.mindview.util.Generator;public class GeneratorsTest{public static int size = 10;public static void test(Class<?> surroundingClass){for(Class<?> type : surroundingClass.getClasses()) //取得这个类对象里面的类{//取得这个类型的数组System.out.println(type.getSimpleName() + ": ");try{Generator<?> g = (Generator<?>)type.newInstance(); //获取一个实例化对象//输出他的计数for(int i = 0; i < size; ++i){System.out.printf(g.next() + " ");}System.out.println();}catch (Exception e){e.printStackTrace();}}}public static void main(String[] args){test(CountingGenerator.class);}}

输出：

Boolean:
true false true false true false true false true false
Byte:
0 1 2 3 4 5 6 7 8 9
Character:
a b c d e f g h i j
Double:
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0
Float:
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0
Integer:
0 1 2 3 4 5 6 7 8 9
Short:
0 1 2 3 4 5 6 7 8 9
String:
abcdefg hijklmn opqrstu vwxyzAB CDEFGHI JKLMNOP QRSTUVW XYZabcd efghijk lmnopqr