Java Scanner Readable

Posted 2021-01-31 飞龙dragon

通过implements(实现)Readbale interface(接口)的 read() method(方法) 实现自己添加字符到buffer里,然后读取

package object;

//: interfaces/RandomWords.java
// Implementing an interface to conform to a method.
import java.nio.*;
import java.util.*;

public class RandomWords implements Readable {
  private static Random rand = new Random(47);
  private static final char[] capitals =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ".toCharArray();
  private static final char[] lowers =
    "abcdefghijklmnopqrstuvwxyz".toCharArray();
  private static final char[] vowels =
    "aeiou".toCharArray();
  private int count; //设置读入多少行
  public RandomWords(int count) { this.count = count; }    
  public int read(CharBuffer cb) {  //read()方法来自Readable接口,Sanner()里也有用到
    if(count-- == 0)
      return -1; // Indicates end of input 
    cb.append(capitals[rand.nextInt(capitals.length)]); //从cpitals里面每次读出一个字符并添加到buffer里面
    for(int i = 0; i < 4; i++) {
      cb.append(vowels[rand.nextInt(vowels.length)]);//从vowels里面每次读出four char 字符并添加到buffer里面
      cb.append(lowers[rand.nextInt(lowers.length)]);//append()方法:添加字符到buffer里面
    }
    cb.append(" ");  //空格和‘
‘功能一样
    
    return 10; // Number of characters appended
  }
  public static void main(String[] args) {
    Scanner s = new Scanner(new RandomWords(10)); 
                             // new RandomWords(10)可以换做任意实现了Readable接口的类所生成的对象
    while(s.hasNext()) //hasNext()通过调用readInput()方法调用read()方法知道read()返回-1结束
      System.out.println(s.next());
  }
} /* Output:
Yazeruyac
Fowenucor
Goeazimom
Raeuuacio
Nuoadesiw
Hageaikux
Ruqicibui
Numasetih
Kuuuuozog
Waqizeyoy
*///:~