XML文件解析数据结构

public void main() {
    XmlTagTree tree = new XmlTagTree();
    while (true) {
        // 获取xml标签
        Tag tag = getTag();
        if (tag.isStartTag()) {
            tree.addNode(tag, XmlTagTree.STATE_START);
        } else if (tag.isEndTag()){
            tree.addNode(null, XmlTagTree.STATE_END);    
        }        
    }
}

class Tag {
    private Tag parent;
    private Tag child;
    private Tag next;
}

public static class XmlTagTree {

    public final static int STATE_START = 0;
    public final static int STATE_END = 1;

    private int mCurrentState = STATE_START;
    private Tag mRoot;
    private Tag mCurrent;
    private XmlTreeOperate[][] mOperates;
    private int mSize = 0;

    public XmlTagTree() {
        mOperates = new XmlTreeOperate[2][2];
        mOperates[STATE_START][STATE_START] = new XmlTreeOperate() {
            @Override
            public void operate(Tag chunk, int state) {
                if (mRoot == null) {
                    // 第一次操作，初始化节点
                    mRoot = chunk;
                    mCurrent = chunk;
                } else {
                    // (START, START) -> addChild
                    mCurrent.child = chunk;
                    chunk.parent = mCurrent;
                    mCurrent = chunk;
                    ++mSize;
                }
            }
        };
        mOperates[STATE_START][STATE_END] = new XmlTreeOperate() {
            @Override
            public void operate(Tag chunk, int state) {
                // (START, END) -> none
                // do not do anything
            }
        };
        mOperates[STATE_END][STATE_START] = new XmlTreeOperate() {
            @Override
            public void operate(Tag chunk, int state) {
                // (END, START) -> addSibling
                 mCurrent.next = chunk;
                chunk.parent = mCurrent.parent;
                mCurrent = chunk;
                ++mSize;
            }
        };
        mOperates[STATE_END][STATE_END] = new XmlTreeOperate() {
            @Override
            public void operate(Tag chunk, int state) {
                // (END, END) -> goParent
                mCurrent = mCurrent.parent;
            }
        };
    }

    public void addNode(Tag chunk, int state) {
        if (mRoot == null && state != STATE_START) {
            throw new RuntimeException("first state in XmlTagTree must be STATE_START");
        }
        mOperates[mCurrentState][state].operate(chunk, state);
        mCurrentState = state;
    }

    private interface XmlTreeOperate {
        void operate(Tag chunk, int state);
    }
}