Bag类的接口的实现与测试（课上测试补做）

Bag类的接口的实现与测试（课上测试补做）

截图

• 由于截图有一定的的限制就没有吧所有的代码截进去，后面有代码。

代码

package ClassTest;

import java.util.Objects;

/**
 * Created by 春旺 on 2017/9/22.
 */
/*
实现接口BagInterface，
声明一个有限长度的T类型的数组用来储存各个类

*/
public class Bag<T> implements BagInterface<T>{
    public Object [] arry = new Object[100];

    /*
    声明一个整形数记录非空的元素
    用循环遍历数组不为空时size 加一
    为空继续循环
    */
    @Override
    public int getCurrentSize() {
        int size = 0;
        for (int i = 0; i < arry.length; i++){
            if (arry[i] != null){
               size = size + 1;
            }
        }
        return size;
    }
/*
遍历数组一发现有非空元素就就变为false 并结束循环
*/
    @Override
    public boolean isEmpty() {
        boolean b = true;
        for (int i = 0;i < arry.length;i++){
            if (arry[i] != null){
              b = false;
              break;
            }
        }

        return b;
    }
/*
遍历数组，在第一个非空的的数组元素并将其变成输入的元素
*/
    @Override
    public boolean add(T newEntry) {
        boolean b = false;
       for (int i = 0;i < arry.length;i++){
           if (arry[i] == null){
               arry[i] = (Object) newEntry;
               b = true;
               break;
           }
       }

      return b;
    }
/*
随意删除，所以将第一个非空的元素变成null
*/
    @Override
    public T remove() {
        T t = null;
        for (int i = 0;i < arry.length;i++){
            if (arry[i] != null){
                t = (T)arry[i];
              arry[i] = null;
                break;
            }
        }

       return t ;
    }
/*
先查找目标元素，未找到返回false。

for循环遍历数组将所有的目标元素变成
*/
    @Override
    public boolean remove(T anEntry) {
        boolean b = false;
        for (int i =0; i < arry.length;i++){
            if (anEntry == arry[i]){
                arry [i] = null;
                b = true;
            }
        }
        return b;
    }
/*
删除所有的元素就将原先声明的数组清空
*/
    @Override
    public void clear() {
        for (int i = 0;i< 100;i++) {
            arry[i] = null;
        }
    }
/*遍历数组将目标元素与数组中的元素一一比较
如果相等就进行计数，返回计数后的总的值
*/
    @Override
    public int getFrequencyOf(T anEntry) {
        int number = 0;
        for (int i =0; i < arry.length;i++){
            if (anEntry == arry[i]){
               number ++;
            }

    }
    return number;
    }
/* 遍历数组将目标元素与数组中的元素一一比较
只要发现有数组中的元素与目标元素相等就退出循环*/
    @Override
    public boolean contains(T anEntry) {
        boolean b = false;
        for (int i =0; i < arry.length;i++){

            if (anEntry == arry[i]){
                arry [i] = null;
                b = true;
                break;
            }
        }
        return b;
    }
}

• 伪代码已经包含在每个方法的开头。

package ClassTest;

import org.junit.Test;

import static org.junit.Assert.*;

/**
 * Created by 春旺 on 2017/9/22.
 */
public class BagTest {
    Bag<Student> bag = new Bag<>();
    Student s1 = new Student();
    @Test
    public void getCurrentSize() throws Exception {

        Student s1 = new Student();

        assertEquals(0,bag.getCurrentSize());
        bag.add(s1);
        assertEquals(1, bag.getCurrentSize());

    }

    @Test
    public void isEmpty() throws Exception {
       assertEquals(true,bag.isEmpty());
        Student s1 = new Student();
        bag.add(s1);
        assertEquals(false,bag.isEmpty());

    }

    @Test
    public void add() throws Exception {
        assertEquals(true,bag.add(null));
        bag.add(s1);
        assertEquals(true,bag.add(s1));
    }

    @Test
    public void remove() throws Exception {
        bag.add(s1);
        bag.remove();
        assertEquals(0,bag.getCurrentSize());

    }

    @Test
    public void remove1() throws Exception {
        Student s2 = new Student();
        Student s3 = new Student();
        Student s4 = new Student();
        bag.add(s1);   bag.add(s2);
        bag.add(s3);   bag.add(s4);
        bag.add(s1);   bag.add(s2);
        bag.add(s3);   bag.add(s4);
        assertEquals(8,bag.getCurrentSize());
        bag.remove(s2);
        assertEquals(6,bag.getCurrentSize());
    }

    @Test
    public void clear() throws Exception {
        for (int i = 0;i<100;i++){
            bag.add(s1);
        }
        assertEquals(100,bag.getCurrentSize());
       bag.clear();
       assertEquals(0,bag.getCurrentSize());

    }

    @Test
    public void getFrequencyOf() throws Exception {
        Student s2 = new Student();
        Student s3 = new Student();
        for (int i = 0;i < 50;i++){
           bag.add(s2);
           bag.add(s1);
        }
        assertEquals(50,bag.getFrequencyOf(s1));
        assertEquals(0,bag.getFrequencyOf(s3));
    }

    @Test
    public void contains() throws Exception {
        Student s2 = new Student();
        Student s3 = new Student();
        for (int i = 0;i < 50;i++){
            bag.add(s2);
            bag.add(s1);
        }
        assertEquals(true,bag.contains(s2));
        assertEquals(false,bag.contains(s3));
    }

}

package ClassTest;

/**
     2 An interface that describes the operations of a bag of objects.
     3
     4 */
 public interface BagInterface<T>
 {
         /**
          * Gets the current number of entries in this bag.
          *
          * @return The integer number of entries currently in the bag.
          */
         public default int getCurrentSize() {
                 return 0;
         }

         /** Sees whether this bag is empty.
          @return True if the bag is empty, or false if not. */
         public boolean isEmpty();

         /** Adds a new entry to this bag.
          @param newEntry The object to be added as a new entry.
          @return True if the addition is successful, or false if not. */
         public boolean add(T newEntry);

         /** Removes one unspecified entry from this bag, if possible.
          @return Either the removed entry, if the removal
          was successful, or null. */
         public T remove();

         /** Removes one occurrence of a given entry from this bag, if possible.
          @param anEntry The entry to be removed.
          @return True if the removal was successful, or false if not. */
         public boolean remove (T anEntry);

         /** Removes all entries from this bag. */
         public void clear();

         /** Counts the number of times a given entry appears in this bag.
          @return The number of times anEntry appears in the bag.
           * @param anEntry The entry to be counted.*/
         public int getFrequencyOf(T anEntry);

         /** Tests whether this bag contains a given entry.
          @param anEntry The entry to locate.
          @return True if the bag contains anEntry, or false if not. */
          public boolean contains(T anEntry);
         /** Retrieves all entries that are in this bag.
          @return A newly allocated array of all the entries in the bag.
          Note: If the bag is empty, the returned array is empty. */

         } // end BagInterf

package ClassTest;

/**
 * Created by 春旺 on 2017/9/22.
 */

public class Student {
   String name;
   int id ;
   public void student(){
       id = 20162324;
       name = "春旺";
   }

}

• 这个类比较简陋，只是拿来测试就没有写的太详细。

总结

对于这次考试来说我在上课时不知道在做什么，对于老师的意图没有了理解，在课后与同学交流的过程中才知道自己的思想太过于的局限，太过于的执着，在遇到困难时没有想办法绕过去，而是一直纠结于这个问题。