/**
* query a set of tra from this single cell
*
* @param inTraSet
* @return
*/
public ArrayList<Entry<Long, GridLeafTraHashItem>> queryTraSet(ArrayList<Long> inTraSet) {
// store result
HashMap<Long, GridLeafTraHashItem> resHash = new HashMap<Long, GridLeafTraHashItem>();
// collect the entry according their page id
HashMap<Integer, ArrayList<Long>> collect = new HashMap<Integer, ArrayList<Long>>();
if (null == inTraSet) return null;
// divide the tra by their page id
for (Long traItem : inTraSet) {
int timeItem =
Configuration.getTime(traItem)
+ Configuration.T_Sample; // time + T_Smaple to get next time
int itemPageId =
getPageIdByTime(
timeItem); // get page id, if page id is PAGE_ID_CUR, it is stored in current tra hash
// put this tra into collect hashmap
ArrayList<Long> itemLongArray = collect.get(itemPageId);
if (null == itemLongArray) {
itemLongArray = new ArrayList<Long>();
collect.put(itemPageId, itemLongArray);
}
itemLongArray.add(traItem); // put tra_id in the same page together
}
Iterator<Entry<Integer, ArrayList<Long>>> itr = collect.entrySet().iterator();
while (itr.hasNext()) {
Entry<Integer, ArrayList<Long>> pageItem = itr.next();
LinkedHashMap<Long, GridLeafTraHashItem> pageTraHash;
if (PAGE_ID_CUR == pageItem.getKey()) { // return current traHash
pageTraHash = traHash;
} else if (PAGE_ID_NIL == pageItem.getKey()) {
pageTraHash = null;
} else {
pageTraHash = loadPageHashTra(pageItem.getKey()); // load from disk
}
// visit every item in this pageTraHash
if (pageTraHash != null) { // if trahash cannot be found, ignore it
for (Long key : pageItem.getValue()) {
int keyTraId = Configuration.getTraId(key); // id
int keyTime = Configuration.getTime(key) + Configuration.T_Sample; // cur+T_Sample
GridLeafTraHashItem glItem =
queryTraIdTimePerTraHash(pageTraHash, keyTraId, keyTime); // get item
if (null != glItem) { // the end of trajectory, do not get result
Long newKey = Configuration.getKey(keyTraId, keyTime);
resHash.put(newKey, glItem);
}
}
}
}
ArrayList<Entry<Long, GridLeafTraHashItem>> res =
new ArrayList<Entry<Long, GridLeafTraHashItem>>(resHash.entrySet());
return res;
}
/**
* query each traHash by queryTime, all points that are more recent(with larger timestamp) than
* inQueryTime are included in query result
*
* @param inTraLinkedHash
* @param inQueryTime
* @param outRes
*/
private void queryTimeRangePerTraHash(
LinkedHashMap<Long, GridLeafTraHashItem> inTraLinkedHash,
int inQueryTime,
ArrayList<Entry<Long, GridLeafTraHashItem>> outRes) {
// visit the linkedhashmap by reverse order, more recent traId has more larger timestamp
ListIterator<Entry<Long, GridLeafTraHashItem>> list =
new ArrayList<Entry<Long, GridLeafTraHashItem>>(inTraLinkedHash.entrySet())
.listIterator(inTraLinkedHash.size());
while (list.hasPrevious()) {
Entry<Long, GridLeafTraHashItem> item = (Entry<Long, GridLeafTraHashItem>) list.previous();
int itemTime = Configuration.getTime(item.getKey());
// the more recent traId, the larger timestamp
if (itemTime >= inQueryTime) {
outRes.add(item);
}
}
}
