public Tweet getTweet(String tweetid) {
Map<String, String> map = cassandra.listColumns(tweetid, TWEETS, false);
return new Tweet(
tweetid.getBytes(),
map.get("uname"),
map.get("body"),
map.get("timestamp") == null ? null : Long.parseLong(map.get("timestamp")));
}
// Data Reading
public User getUserByUsername(String uname) {
Args.notNull(uname, "Name");
String password = cassandra.readColumn(uname, "password", USERS);
if (null == password || password.equals("")) {
return null;
}
return new User(uname.getBytes(), password);
}
public void removeFriends(String from_uname, List<String> to_unames) {
Mutator<String> mutator = cassandra.getMutator();
for (String uname : to_unames) {
mutator
.addDeletion(from_uname, FRIENDS, uname, SE)
.addDeletion(uname, FOLLOWERS, from_uname, SE);
mutator.decrementCounter(from_uname, MISC_COUNTS, "friends", 1);
mutator.decrementCounter(uname, MISC_COUNTS, "followers", 1);
}
mutator.execute();
}
public void addFriends(String from_uname, List<String> to_unames) {
long timestamp = System.currentTimeMillis();
Mutator<String> mutator = cassandra.getMutator();
for (String uname : to_unames) {
mutator
.addInsertion(
from_uname, FRIENDS, HFactory.createStringColumn(uname, String.valueOf(timestamp)))
.addInsertion(
uname, FOLLOWERS, HFactory.createStringColumn(from_uname, String.valueOf(timestamp)))
.addCounter(from_uname, MISC_COUNTS, HFactory.createCounterColumn("friends", 1))
.addCounter(uname, MISC_COUNTS, HFactory.createCounterColumn("followers", 1));
}
mutator.execute();
}
private Timeline getLine(
String COL_FAM, String uname, String startkey, int count, final boolean reversed) {
Map<String, String> map = cassandra.listColumns(uname, COL_FAM, startkey, count, reversed);
if (null == map || 0 == map.size()) {
return null;
}
List<String> tweetids = ImmutableList.<String>copyOf(map.values());
List<Tweet> tweets = getTweetsForTweetids(tweetids);
return new Timeline(tweets, Long.valueOf(String.valueOf(getLast(map.keySet(), 0))));
/*
* Selector selector = makeSel(); List<Column> timeline; byte[]
* longTypeStartKey = (startkey.equals("") ? new byte[0] :
* NumberHelper.toBytes(Long.parseLong(startkey))); try { timeline =
* selector.getColumnsFromRow(uname, COL_FAM,
* Selector.newColumnsPredicate(longTypeStartKey,new
* byte[0],true,count+1), RCL); } catch (Exception e) {
* log.error("Unable to retrieve timeline for uname: " + uname); return
* null; } Long mintimestamp = null; if (timeline.size() > count) {
* //find min timestamp mintimestamp = Long.MAX_VALUE; Column removeme =
* timeline.get(0); //This cannot fail. Count is 0+, and size is thus
* 1+. Only needed for initialization. for (Column c : timeline) { long
* ctime = ByteBuffer.wrap(c.name).getLong(); if (ctime < mintimestamp)
* { mintimestamp = ctime; removeme = c; } } //eject column from list
* after saving the timestamp timeline.remove(removeme); }
* ArrayList<String> tweetids = new ArrayList<String>(timeline.size());
* for (Column c : timeline) { tweetids.add(bToS(c.value)); }
* Map<String, List<Column>> unordered_tweets = Collections.emptyMap();
* try { unordered_tweets = selector.getColumnsFromRows(tweetids,
* TWEETS, SPall(), RCL); } catch (Exception e) {
* log.error("Unable to retrieve tweets from timeline for uname: " +
* uname); return null; } //Order the tweets by the ordered tweetids
* ArrayList<Tweet> ordered_tweets = new
* ArrayList<Tweet>(tweetids.size()); for (String tweetid : tweetids) {
* ordered_tweets
* .add(makeTweet(tweetid.getBytes(),unordered_tweets.get(tweetid))); }
* return new Timeline(ordered_tweets, mintimestamp);
*/
// return null;
}
public void saveTweet(Tweet tweet) {
long timestamp = System.currentTimeMillis();
String key = bToS(tweet.getKey());
Mutator<String> mutator = cassandra.getMutator();
mutator
.addInsertion(key, TWEETS, createStringColumn("uname", tweet.getUname()))
.addInsertion(key, TWEETS, createStringColumn("body", tweet.getBody()))
.addInsertion(key, TWEETS, createStringColumn("timestamp", String.valueOf(timestamp)))
.addInsertion(
tweet.getUname(), USERLINE, createStringColumn(String.valueOf(timestamp), key))
.addInsertion(PUBLIC, USERLINE, createStringColumn(String.valueOf(timestamp), key))
.addCounter(tweet.getUname(), MISC_COUNTS, HFactory.createCounterColumn("tweets", 1))
.addCounter(PUBLIC, MISC_COUNTS, HFactory.createCounterColumn("tweets", 1));
ArrayList<String> followerUnames = new ArrayList<String>(getFollowerUnames(tweet.getUname()));
for (String follower : followerUnames) {
mutator.addInsertion(follower, TIMELINE, createColumn(timestamp, key));
}
mutator.execute();
}
// Data Writing
public void saveUser(User user) {
cassandra.updateColumn(bToS(user.getKey()), user.getPassword(), "password", USERS);
}
public long getCounter(String uname, String counter) {
return cassandra.countColumns(uname, counter, MISC_COUNTS);
}
// Helpers
private List<String> getFriendOrFollowerUnames(String COL_FAM, String uname, int count) {
Map<String, String> map = cassandra.listColumns(uname, COL_FAM, null, count, false);
return ImmutableList.<String>copyOf(map.keySet());
}
