gistfile1.java

//我需要的用法是 RoadInfo = RoadInfoHash.get(起點).get(終點)
//所以RoadInfoHash是一個雙層的HashMap，RoadInfoHash.get(起點)會得到一個HashMap
while ((mRi = mRiCursor.next()) != null) {
	//如果Hash的key內沒這個起點，表示他還沒被new，就new出來，這個if不能拿掉
	if( !RoadInfoHash.containsKey(mRi.FNode.NodeId) )
		RoadInfoHash.put(mRi.FNode.NodeId, new HashMap<String,RoadInfoPlusEntity>() );
	//這個if想拿掉也沒關係，加if是為了不要重複賦值而已
	if( !RoadInfoHash.get(mRi.FNode.NodeId).containsKey(mRi.TNode.NodeId) )
		RoadInfoHash.get(mRi.FNode.NodeId).put(mRi.TNode.NodeId, mRi);
	
	//路是雙向的，表示這條路允許這麼抓RoadInfo = RoadInfoHash.get(終點).get(起點)
	if( mRi.Dir == 0 ){
		//跟上面動作一樣，拿終點去看HashMap被new出來沒
		if( !RoadInfoHash.containsKey(mRi.TNode.NodeId) )
			RoadInfoHash.put(mRi.TNode.NodeId, new HashMap<String,RoadInfoPlusEntity>() );
		if( !RoadInfoHash.get(mRi.TNode.NodeId).containsKey(mRi.FNode.NodeId) )
			RoadInfoHash.get(mRi.TNode.NodeId).put(mRi.FNode.NodeId, mRi.swapNode());
	}
	
}