Java单链表

/**
 * 单链表
 * 
 * @author AfuAnthony
 *
 * @param <DATA>数据域类型泛型
 * 
 * @apiNote 如果有元素，则index从0开始。
 * 初始化时，size为0，只包含一个head节点。
 * 
 */
public class AfuLinkList<DATA> {
    private Node mHead;
    private int mSize;

    public AfuLinkList() {
        mHead = new Node();
        mSize = 0;
    }


    public boolean add(DATA data) {
        Node newNode = new Node(data);
        Node lastNode = getNode(getSize()-1);
        if(lastNode!=null) {
            lastNode.next=newNode;
            mSize++;
            return true;
        }
        return false;
    }

    public boolean  delete() {
        if(mSize==0) {
            return false;
        }
        Node lastSecondNode;
        lastSecondNode = getNode(getSize()-1);
        if(lastSecondNode!=null) {
            lastSecondNode.next=null;
            mSize--;
            return true;
        }
        return false;
        
    }
    
    public boolean insert(int index, DATA data) {
        Node newNode = new Node(data);
        if(index>=0&&index<getSize()) {
            Node insertPreNode = getNode(index-1);
            if(insertPreNode!=null) {
            Node insertPositionNode =   insertPreNode.next;
                if(insertPositionNode!=null) {
                    insertPreNode.next=newNode;
                    newNode.next=insertPositionNode;
                    mSize++;
                    return true;
                }
            }
        }
        return false;
    }

    public boolean modify(int index, DATA data) {
        if(index>=0&&index<getSize()) {
            Node node = getNode(index);
            if(node!=null) {
                node.setData(data);
                return true;
            }
        }
        return false;
    }

    public Node getNode(int index) {
        if(index==-1) {
            return mHead;
        }else if(index>-1&&index<mSize) {
            Node tmpNode = mHead;
            for(int i=0;i<=index;i++) {
                tmpNode = tmpNode.next;
            }
            return tmpNode;
        }
        return null;
    }

    public int getSize() {
        return mSize;
    }
    
    
    public boolean isEmpty(){
        return mSize==0;
    }
    
    @Override
    public String toString() {
        int listSize = mSize;
        StringBuilder stringBuilder = new StringBuilder();
        stringBuilder.append("size=")
        .append(listSize)
        .append("\r\n");
        if(!isEmpty()) {
            Node tmpNode = mHead;
            for(int index=0;index<listSize;index++) {
                tmpNode = tmpNode.next;
                stringBuilder.append('[')
                .append(index)
                .append(']')
                .append("=")
                .append(tmpNode.getData())
                .append("\r\n");
            }
        }
        return stringBuilder.toString();
    }

    public void print() {
        System.out.println(toString());
    }
    
    public class Node {
        private DATA data;
        private Node next;

        public Node() {
        }

        public Node(DATA data, AfuLinkList<DATA>.Node next) {
            super();
            this.data = data;
            this.next = next;
        }

        public Node(DATA data) {
            super();
            this.data = data;
        }

        public Node(AfuLinkList<DATA>.Node next) {
            super();
            this.next = next;
        }

        public DATA getData() {
            return data;
        }

        public void setData(DATA data) {
            this.data = data;
        }

        public Node getNext() {
            return next;
        }

        public void setNext(Node next) {
            this.next = next;
        }

    }

    /**
     * test
     * @param args
     */
    public static void main(String[] args) {
        AfuLinkList<Integer> linkList = new AfuLinkList<>();
        System.out.println(linkList.add(3));
        System.out.println(linkList.add(2));
        linkList.add(1);
        linkList.insert(2, 0);
        linkList.print();
        linkList.delete();
        linkList.print();
        linkList.modify(2, 1);
        linkList.print();
    }

}