位运算的权限应用

package cn.test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Random;

/**
 * yicha 
 * Sep 5, 2008 
 */

public class BitOperator {
	
	public String[] getData(){
//		String[] result={"1","5","7","12","16","19","30"};
//		String[] result=new String[10];
//		for(int i=1;i<10;i+=2){
//			result[i]=String.valueOf(1*2*i);
//		}
		String[] result={"1","2","4","8","10","20","40","80","160","320","640","1280","2560","5120"};
//		String[] result={"1","2","4","8","10","20","40","80","160"};
		return result;
	}
	
	/**
	 * 根据具体的值解析到权限值，比如：具体的权限到一个权限值
	 * 存储这个值
	 * @param arg
	 * @return
	 */
	public Long doBitOp(String[] arg){
		long result = 0;
		for (int i = 0; i < arg.length; i++) {
			result |= Long.parseLong(arg[i], 16);
		}
		return new Long(result);
	}
	
	/**
	 * 解析具体的值到对应的值，比如：权限值解析到具体的权限 15解析为(1,2,4,8)
	 * @param arg
	 * @return
	 */
	public String[] phaseBitOp(long arg){
		List list=new ArrayList();
		int number=1;
		for(int i=0;i<16;i++){
			long temp=number<<i;//左移i位,数变大,2的i次方
			if((temp&arg)>0){
				list.add(Long.toHexString(temp));
			}
		}
		String[] result=new String[list.size()];
		for(int i=0;i<list.size();i++){
			result[i]=list.get(i).toString();
		}
		return result;
	}
	
	/**
	 * 二分查找法,没有找到则返回-1,否则返回查找到的位置，从0开始
	 * @param a
	 * @param target
	 * @return
	 */
	public int binarySearch(int a[],int target){
		int low=0;
		int high=a.length-1;
		while(low<=high){
			int mid=(low+high)>>>1;//无符号右移一位，即相当于绝对值除2
			int midValue=a[mid];
			if(midValue<target){
				low=mid+1;
			}else if(midValue>target){
				high=mid-1;
			}else{
				return mid;
			}			
		}
		return -1;
	}
	
	/**
	 * 随机产生数组，数组长度不大于maxArraySize+1，数据不大于maxValue
	 * @param maxArraySize
	 * @param maxValue
	 * @return
	 */
	public int[] generateRandomSortedArray(int maxArraySize, int maxValue) { 
		Random rand=new Random();
		int arraySize = 1 + rand.nextInt(maxArraySize); //至少保证有1个数据
		int[] randomArray = new int[arraySize]; 
		for (int i = 0; i < arraySize; i++) { 
			randomArray[i] = rand.nextInt(maxValue); 
		} 
		Arrays.sort(randomArray); 
		return randomArray;
	}
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		BitOperator bit=new BitOperator();
		int a[]=bit.generateRandomSortedArray(10, 50);
		for(int i=0;i<a.length;i++){
			System.out.println(""+a[i]);
		}
		
		System.out.println("二分法查找结果："+bit.binarySearch(a, 15));
//		BitOperator bit=new BitOperator();
//		Long result=bit.doBitOp(bit.getData());		
//		System.out.println(result);
//		long temp=15;		
//		String[] phaseBitStr=bit.phaseBitOp(temp);
//		for(int i=0;i<phaseBitStr.length;i++){
//			System.out.print(phaseBitStr[i]+",");
//		}
		
		
	}

}