GenericArray
GenericArray.java 源码
package datastructure.array;
import java.util.Arrays;
/**
* @author roseduan[roseduan520@gmail.com]
* @time 2019/12/4 22:52
* @description 动态数组实现
*/
public class GenericArray<T> {
private static final int DEFAULT_CAPACITY = 16;
private Object[] data;
private int capacity;
private int size;
public GenericArray(int capacity) {
this.data = new Object[capacity];
this.capacity = capacity;
this.size = 0;
}
public GenericArray(){
this(DEFAULT_CAPACITY);
}
/**
* 查找
*/
@SuppressWarnings("unchecked")
public T get(int index){
if (index < 0 || index >= size){
throw new IllegalArgumentException("the index is illegal!");
}
return (T) data[index];
}
/**
* 插入到某个位置
*/
public boolean add(int index, T val){
if (index < 0 || index > size){
throw new IllegalArgumentException("the index is illegal!");
}
System.arraycopy(data, index, data, index + 1, size - index);
data[index] = val;
if (++size >= capacity){
resize(capacity + (capacity >> 1));
}
return true;
}
/**
* 插入到末尾
*/
public boolean add(T val){
return add(size, val);
}
/**
* 删除
*/
@SuppressWarnings("unchecked")
public T remove(int index) {
if (index < 0 || index >= size){
throw new IllegalArgumentException("the index is illegal!");
}
T res = (T) data[index];
System.arraycopy(data, index + 1, data, index, size - index - 1);
data[--size] = null;
return res;
}
/**
* 是否包含
*/
public boolean contains(T value){
if (size == 0){
return false;
}
if (value == null){
for (int i = 0; i < size; i++) {
if (data[i] == null){
return true;
}
}
} else {
for (int i = 0; i < size; i++) {
if (value.equals(data[i])){
return true;
}
}
}
return false;
}
@Override
public String toString() {
if (size == 0){
return "[]";
}
StringBuilder sb = new StringBuilder("[");
for (int i = 0; i < size; i++){
sb.append(data[i]);
if (data[i + 1] == null){
sb.append("]");
break;
}
sb.append(",").append(" ");
}
return sb.toString();
}
/**
* 扩容方法
*/
private void resize(int newCapacity){
this.data = Arrays.copyOf(data, newCapacity);
this.capacity = newCapacity;
}
}
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