随机实例，随机值

/**
 * 随机项
 * @author healy
 *
 * @param <E>
 */
public class RandomEntry<E> {
    /**概率,单位%%(万分之)*/
    private int probability;
    /**概率对应的物品*/
    private E entry;
    
    public RandomEntry(){
        
    }

    /**
     * 
     * @param p 概率单位%%(取值范围：[0-10000))
     * @param entry
     */
    public RandomEntry(int p, E entry) {
        this.probability = p;
        this.entry = entry;
    }
    
    /**
     * 
     * @param p 小数(取值范围：[0-1))
     * @param entry
     */
    public RandomEntry(double p, E entry) {
        this.probability = (int)(p*RandomInstance.maxBaseInt);
        this.entry = entry;
    }

    public int getProbability() {
        return probability;
    }

    public void setProbability(int probability) {
        this.probability = probability;
    }

    public E getEntry() {
        return entry;
    }

    public void setEntry(E entry) {
        this.entry = entry;
    }

    @Override
    public String toString()
    {
        return "RandomEntry [probability=" + probability + ", entry=" + entry + "]";
    }

}

View Code

  1 import java.util.ArrayList;
  2 import java.util.List;
  3 import java.util.Random;
  4 
  5 /**
  6  * 随机实例，应用于一个随机事件场景
  7  * 
  8  * @author healy
  9  * 
 10  */
 11 public class RandomInstance<E>
 12 {
 13     
 14     Random r = new Random();
 15     
 16     /** 总概率值 */
 17     int totalProbability = 0;
 18     
 19     public final static int maxBaseInt = 10000;
 20     
 21     /**
 22      * 随机项列表
 23      */
 24     List<RandomEntry<?>> reList = new ArrayList<RandomEntry<?>>();
 25     
 26     ConditionController<?> cc;
 27     
 28     public RandomInstance()
 29     {
 30         
 31     }
 32     
 33     public RandomInstance(ConditionController<?> cc)
 34     {
 35         this.cc = cc;
 36         
 37     }
 38     
 39     /**
 40      * 根据随机概率获取对应的实例
 41      * 
 42      * @return
 43      */
 44     public E getRandomEntry()
 45     {
 46         E retObj = null;
 47         
 48         int randomValue = r.nextInt(totalProbability);
 49         
 50         int curPoint = 0;
 51         
 52         int retry = 0;
 53         
 54         for (int i = 0; i < reList.size(); i++)
 55         {
 56             RandomEntry<?> re = reList.get(i);
 57 //            LogUtil.info("i:" + i + "re:" + re + "curPoint:" + curPoint + "totalProbability:" + totalProbability
 58 //                + "retry:" + retry);
 59             if (randomValue >= curPoint && randomValue < curPoint + re.getProbability())
 60             {
 61                 if (cc != null && cc.rejectByCondition(re))
 62                 {
 63                     // 如果当前概率物品已经达到最大限制，则跳过
 64                     randomValue = (randomValue + re.getProbability()) % totalProbability;
 65                     if (++retry >= reList.size())
 66                     {// 最大跳过次数为列表长度
 67                         break;
 68                     }
 69                 }
 70                 else
 71                 {
 72                     retObj = (E)re.getEntry();
 73                     if (cc != null)
 74                     {
 75                         // 更新条件值
 76                         cc.updateConditionValue(re);
 77                     }
 78                     break;
 79                 }
 80             }
 81             else
 82             {
 83                 curPoint += re.getProbability();
 84             }
 85         }
 86         
 87         return retObj;
 88         
 89     }
 90     
 91     public void addRandomEntry(RandomEntry<?>... entries)
 92     {
 93         int total = 0;
 94         if (entries.length > 0)
 95         {
 96             
 97             // 遍历参数内容
 98             for (RandomEntry<?> re : entries)
 99             {
100                 total += re.getProbability();
101                 reList.add(re);
102             }
103             totalProbability += total;
104         }
105     }
106     
107     public void removeRandomEntry(RandomEntry<?>... entries)
108     {
109         int total = 0;
110         if (entries.length > 0)
111         {
112             
113             // 遍历参数内容
114             for (RandomEntry<?> re : entries)
115             {
116                 total += re.getProbability();
117                 reList.remove(re);
118             }
119             totalProbability -= total;
120         }
121     }
122     
123     @Override
124     public String toString()
125     {
126         return "RandomInstance [r=" + r + ", totalProbability=" + totalProbability + ", reList=" + reList + ", cc="
127             + cc + "]";
128     }
129     
130 }

View Code

 1 RandomInstance<Integer> randomIns = new RandomInstance<Integer>();
 2 
 3 for (Mine_reward info : rewardList) {
 4 
 5     RandomEntry<Integer> re = new RandomEntry<Integer>(info.getWeight(), info.getRewardId());
 6 
 7     randomIns.addRandomEntry(re);
 8 }
 9 
10 int rewardId = randomIns.getRandomEntry();

View Code

这个博客主要是javaEE相关或者不相关的记录， hadoop与spark的相关文章我写在下面地址的博客啦~ http://www.cnblogs.com/sorco

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原文地址：https://www.cnblogs.com/orco/p/6278901.html