Java 基於數組自定義實現容量不可變向量Vector

背景：假定集合 S 由 n 個元素組成，它們按照線性次序存放，於是我們就可以直接訪問其中的第一個元素、第二個元素、第三個元素……。也就是說，通過[0, n-1]之間的每一個整數，都可以直接訪問到唯一的元素 e，而這個整數就等於 S 中位於 e 之前的元素個數⎯⎯在此，我們稱之爲該元素的秩（ Rank）。不難看出，若元素 e 的秩爲 r，則只要 e 的直接前驅（或直接後繼）存在，其秩就是 r-1（或 r+1）。這一定義與 Java、 C++之類的程序語言中關於數組元素的編號規則是一致的。支持通過秩直接訪問其中元素的序列，稱作向量（ Vector）或數組列表（ Array list）。實際上，秩這一直觀概念的功能非常強大，它可以直接指定插入或刪除元素的位置。

向量ADT各方法定義如下:

基於數組，可以直接實現向量 ADT。我們借用一個數組 array[]，其中 array[i]分別存放一個引用，指向秩爲position 的向量元素。爲此， array[]的容量 CAPACITY 需要足夠大，還需要設置一個實例變量 size 指示向量的實際規模。

具體代碼實現：
Vector 接口：

/**
 * Vector Interface
 */
package com.vector_and_array;

/**
 * @author gannyee
 *
 */
public interface VectorInterface {

    //Get size of vector
    public int getSize();

    //Is empty
    public boolean isEmpty();

    //Get element at rank
    public Object getAtRank(int position) throws ExceptionBoundaryExceed;

    //Replace element at rank
    public void replaceAtRank(int position,Object element) throws ExceptionBoundaryExceed;

    //Insert element at rank
    public void insertAtRank(int position,Object element) throws ExceptionBoundaryExceed;

    //Remove element at rank
    public void removeAtRank(int position) throws ExceptionBoundaryExceed;

    //Travel all elements
    public void getAllelements();
}

自定義ExceptionBoundaryExceed類：

package com.vector_and_array;
/**
 * @author gannyee
 * Exception for boundaryExceed
 */
public class ExceptionBoundaryExceed extends Exception{
    //Constructor overload
    public ExceptionBoundaryExceed(String message){
        super(message);
    }
}

Vector具體實現
VectorBasicOnArray類：

package com.vector_and_array;

import java.util.Arrays;

public class VectorBasicOnArrays implements VectorInterface {
    //Define static variable
    private static final int CAPACITY = 1024;
    //Declared size of vector
    private static int size;
    //Declared array for vector
    Object[] array;

    //Constructor
    public VectorBasicOnArrays(){
        size = 0;
        array = new Object[CAPACITY];
    }

    @Override
    public int getSize() {
        return size;
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    @Override
    public Object getAtRank(int position) throws ExceptionBoundaryExceed{
        if(position < 0 || position > size)
            throw new ExceptionBoundaryExceed("Vector exceed! ");
        return array[position];
    }

    @Override
    public void replaceAtRank(int position, Object element) throws ExceptionBoundaryExceed{
        if(position < 0 || position > size)
            throw new ExceptionBoundaryExceed("Vector exceed! ");
        array[position] = element;
        System.out.println("Element replaced is: " + array[position] + " at position: " + position);
    }

    @Override
    public void insertAtRank(int position, Object element) throws ExceptionBoundaryExceed{
        if(position < 0 || position > size)
            throw new ExceptionBoundaryExceed("Vector exceed! ");
        if(size > CAPACITY)
            throw new ExceptionBoundaryExceed("Vector overflow! ");
        for(int i = size;i >= position;i --)
            array[i + 1] = array[i];
        array[position] = element;
        size ++;
        System.out.println("Element you insert is: " + element + " at position: " + position);
    }

    @Override
    public void removeAtRank(int position) throws ExceptionBoundaryExceed{
        if(position < 0 || position > size)
            throw new ExceptionBoundaryExceed("Vector exceed! ");
        System.out.println("Element you remove is: " + array[position]);
        for(int i = position;i <= size - 1;i ++)
            array[i] = array[i + 1];
        size --;
    }

    @Override
    public void getAllelements() {
        Object[] arrayTravel = new Object[size];

        for(int i = 0;i < arrayTravel.length;i ++)
            arrayTravel[i] = array[i];
        System.out.println("All elements are: " + Arrays.toString(arrayTravel));
    }


}

測試代碼：

package com.vector_and_array;

/**
 * Test
 * @author gannyee
 *
 */
public class VectorTest {

    public static void main(String[] args) throws ExceptionBoundaryExceed {

        //Define VectorBasicOnArrat class
        VectorBasicOnArrays vba = new VectorBasicOnArrays();

        System.out.println("Size: " + vba.getSize());
        System.out.println("Is empty? " + vba.isEmpty());

        vba.insertAtRank(0, 1);
        vba.insertAtRank(1, 2);
        vba.insertAtRank(2, 3);
        vba.insertAtRank(3, 4);
        vba.insertAtRank(4, 5);
        vba.insertAtRank(5, 6);
        vba.insertAtRank(5, 7);
        vba.insertAtRank(6, 8);
        System.out.println("Size: " + vba.getSize());
        System.out.println("Is empty? " + vba.isEmpty());
        vba.getAllelements();

        vba.replaceAtRank(0, 12);
        vba.replaceAtRank(1, 13);
        vba.replaceAtRank(2, 14);
        vba.replaceAtRank(3, 15);
        System.out.println("Size: " + vba.getSize());
        System.out.println("Is empty? " + vba.isEmpty());
        vba.getAllelements();

        vba.removeAtRank(7);
        vba.removeAtRank(5);
        vba.removeAtRank(4);
        vba.removeAtRank(1);
        vba.removeAtRank(0);
        System.out.println("Size: " + vba.getSize());
        System.out.println("Is empty? " + vba.isEmpty());
        vba.getAllelements();
    }

}

測試結果：

Size: 0
Is empty? true
Element you insert is: 1 at position: 0
Element you insert is: 2 at position: 1
Element you insert is: 3 at position: 2
Element you insert is: 4 at position: 3
Element you insert is: 5 at position: 4
Element you insert is: 6 at position: 5
Element you insert is: 7 at position: 5
Element you insert is: 8 at position: 6
Size: 8
Is empty? false
All elements are: [1, 2, 3, 4, 5, 7, 8, 6]
Element replaced is: 12 at position: 0
Element replaced is: 13 at position: 1
Element replaced is: 14 at position: 2
Element replaced is: 15 at position: 3
Size: 8
Is empty? false
All elements are: [12, 13, 14, 15, 5, 7, 8, 6]
Element you remove is: 6
Element you remove is: 7
Element you remove is: 5
Element you remove is: 13
Element you remove is: 12
Size: 3
Is empty? false
All elements are: [14, 15, 8]

相關文字借鑑引用 數據結構與算法（ Java 描述）鄧俊輝 著

未完待續。。。。
基於數組自定義實現容量可變的向量Vector!

源碼在github上：https://github.com/gannyee/JavaDataStruct