Array.java

public class Array<E> {
	private E[] data;
	private int size;
	
	public Array(int capacity) {
		data=(E[])new Object[capacity];
		size=0;
	}
	public Array() {
		this(10);
	}
	public Array(E[] arr) {
		data=(E[])new Object[arr.length];
		for(int i=0;i<arr.length;i++) {
			data[i]=arr[i];
		}
		size=arr.length;
	}
	public int getSize() {
		return size;
	}
	public int getCapacity() {
		return data.length;
	}
	public boolean isEmpty() {
		return size==0;
	}
	public void addLast(E e) {
//		if(size==data.length) {
//			throw new IllegalArgumentException("array is full");
//		}
//		data[size]=e;
//		size++;
		add(size,e);
	}
	public void addFrist(E e) {
		add(0,e);
	}
	public void add(int index,E e) {
//		if(size==data.length) {
//			throw new IllegalArgumentException("array is full");
//		}
		if(index<0||index>size) {
			throw new IllegalArgumentException("add failed");
		}
		if(size==data.length) {
			resize(2*data.length);
		}
		for(int i=size-1;i>=index;i--) {
			data[i+1]=data[i];
		}
		data[index]=e;
		size++;
	}
	public E get(int index) {
		if(index<0||index>=size) {
			throw new IllegalArgumentException("index is illegal");
		}
		return data[index];
	}
	public E getLast() {
		return get(size-1);
	}
	public E getFrist() {
		return get(0);
	}
	void set(int index,E e) {
		if(index<0||index>=size) {
			throw new IllegalArgumentException("index is illegal");
		}
		data[index]=e;
	}
	@Override
	public String toString() {
		StringBuilder res=new StringBuilder();
		res.append(String.format("array :size=%d ,capacity = %d\n",size,data.length));
		res.append('[');
		for(int i=0;i<size;i++) {
			res.append(data[i]);
			if(i!=size-1) {
				res.append(",");
			}
		}
		res.append(']');
		return res.toString();
	}
	public boolean contains(E e) {
		for(int i=0;i<size;i++) {
			if(data[i]==e) {
				return true;
			}
		}
		return false;
	}
	public int find(E e) {
		for(int i=0;i<size;i++) {
			if(data[i].equals(e)) {
				return i;
			}
		}
		return -1;
	}
	public E remove(int index) {
		if(index<0||index>=size) {
			throw new IllegalArgumentException("index is illegal");
		}
		E re=data[index];
		for(int i=index+1;i<size;i++) {
			data[i-1]=data[i];
		}
		size--;
		data[size]=null;
		if(size==data.length/2) {
			resize(data.length/2);
		}
		return re;
	}
	public E removeFirst() {
		return remove(0);
	}
	public E removeLast() {
		return remove(size-1);
	}
	public void removeElement(E e) {
		int index =find(e);
		if(index!=-1) {
			remove(index);
		}
	}
	
	
	public void swap(int i,int j) {
		if(i<0||i>=size||j<0||j>=size) {
			throw new IllegalArgumentException("index is illegal.");
		}
		E t=data[i];
		data[i]=data[j];
		data[j]=t;
	}
	private void resize(int newCapacity) {
		E[] newData=(E[])new Object[newCapacity];
		for(int i=0;i<size;i++) {
			newData[i]=data[i];
		}
		data=newData;
	}
}