XML文件解析數據結構
阿新 • • 發佈：2017-10-09
spa private first nal runtime 兄弟節點 節點 .com 技術分享
最近在解析Android安裝包內經過編譯的二進制XML文件時想在內存中建立起其對應的樹結構。
想了一早晨，思路如下圖。
多叉樹中的每個節點除了有子節點和兄弟節點以外還有一個指針指向父節點，然後根據狀態轉移圖執行相應的代碼就行。
public void main() { XmlTagTree tree = new XmlTagTree(); while (true) { // 獲取xml標簽 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 intSTATE_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] = newXmlTreeOperate() { @Override public void operate(Tag chunk, int state) { if (mRoot == null) { // 第一次操作，初始化節點 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); } }
XML文件解析數據結構