Examples with LinkedList java.util.LinkedList used on opensource projects

Example 86 with LinkedList

use of java.util.LinkedList in project rest.li by linkedin.

the class DegraderLoadBalancerTest method testDegraderLoadBalancerSimulator.

private void testDegraderLoadBalancerSimulator(DegraderLoadBalancerStrategyAdapter adapter, TestClock clock, long timeInterval, List<TrackerClient> clients, double qps, DegraderImpl.Config degraderConfig) {
    long clusterGenerationId = 1;
    double overrideDropRate = 0.0;
    //simulate latency 4000 ms
    //1st round we use LOAD_BALANCING strategy. Since we have a high latency we will decrease the number of points
    //from 100 to 80 (transmissionRate * points per weight).
    TrackerClient resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, true, 0.0, 4000, false, false);
    assertNotNull(resultTC);
    //2nd round drop rate should be increased by DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP
    overrideDropRate += DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, false, overrideDropRate, 4000, false, false);
    //3rd round. We alternate back to LOAD_BALANCING strategy and we drop the points even more
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, true, overrideDropRate, 4000, false, false);
    //4th round. The drop rate should be increased again like 2nd round
    overrideDropRate += DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, false, overrideDropRate, 4000, false, false);
    //5th round. Alternate to changing hash ring again.
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, true, overrideDropRate, 4000, false, false);
    //6th round. Same as 5th round, we'll increase the drop rate
    overrideDropRate += DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 4000, false, false);
    //7th round. The # of point in hashring is at the minimum so we can't decrease it further. At this point the client
    //is in recovery mode. But since we can't change the hashring anymore, we'll always in CALL_DROPPING mode
    //so the next strategy is expected to be LOAD_BALANCING mode.
    overrideDropRate += DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 4000, false, false);
    //8th round. We'll increase the drop rate to the max.
    overrideDropRate += DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_UP;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 4000, false, false);
    //9th round, now we'll simulate as if there still a call even though we drop 100% of all request to get
    //tracker client. The assumption is there's some thread that still holds tracker client and we want
    //to make sure we can handle the request and we can't degrade the cluster even further.
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 4000, false, false);
    //10th round, now we'll simulate as if there's no call because we dropped all request
    //even though we are in LOAD_BALANCING mode and this tracker client is in recovery mode and there's no call
    //so the hashring doesn't change so we go back to reducing the drop rate to 0.8 and that means the next
    //strategy is LOAD_BALANCE
    overrideDropRate -= DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_DOWN;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, 0.0, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 4000, false, false);
    //11th round, this time we'll simulate the latency is now 1000 ms (so it's within low and high watermark). Drop rate
    //should stay the same and everything else should stay the same
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, overrideDropRate, 1000, false, false);
    //we'll simulate the client dying one by one until all the clients are gone
    int numberOfClients = clients.size();
    HashSet<URI> uris = new HashSet<URI>();
    HashSet<URI> removedUris = new HashSet<URI>();
    for (TrackerClient client : clients) {
        uris.add(client.getUri());
    }
    LinkedList<TrackerClient> removedClients = new LinkedList<TrackerClient>();
    //loadBalancing strategy will always be picked because there is no hash ring changes
    boolean isLoadBalancingStrategyTurn = true;
    for (int i = numberOfClients; i > 0; i--) {
        TrackerClient removed = clients.remove(0);
        uris.remove(removed.getUri());
        removedClients.addLast(removed);
        removedUris.add(removed.getUri());
        clusterGenerationId++;
        resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, isLoadBalancingStrategyTurn, overrideDropRate, 1000, false, false);
        if (i == 1) {
            assertNull(resultTC);
        } else {
            //the override drop rate is 0.8)
            if (resultTC != null) {
                assertTrue(uris.contains(resultTC.getUri()));
                assertFalse(removedUris.contains(resultTC.getUri()));
            }
        }
    }
    assertTrue(uris.isEmpty());
    assertTrue(clients.isEmpty());
    assertEquals(removedUris.size(), numberOfClients);
    assertEquals(removedClients.size(), numberOfClients);
    //we'll simulate the client start reviving one by one until all clients are back up again
    for (int i = numberOfClients; i > 0; i--) {
        TrackerClient added = removedClients.remove(0);
        //we have to create a new client. The old client has a degraded DegraderImpl. And in production enviroment
        //when a new client join a cluster, it should be in good state. This means there should be 100 points
        //in the hash ring for this client
        TrackerClient newClient = new TrackerClient(added.getUri(), getDefaultPartitionData(1d), new TestLoadBalancerClient(added.getUri()), clock, degraderConfig);
        clients.add(newClient);
        uris.add(added.getUri());
        removedUris.remove(added.getUri());
        clusterGenerationId++;
        resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, isLoadBalancingStrategyTurn, overrideDropRate, 1000, false, false);
        if (resultTC != null) {
            assertTrue(uris.contains(resultTC.getUri()));
            assertFalse(removedUris.contains(resultTC.getUri()));
        }
    }
    //the number of points because there is no hash ring changes
    for (overrideDropRate -= DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_DOWN; overrideDropRate >= 0; overrideDropRate -= DegraderLoadBalancerStrategyConfig.DEFAULT_GLOBAL_STEP_DOWN) {
        resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, false, overrideDropRate, 300, false, false);
    }
    //we should have recovered fully by this time
    overrideDropRate = 0.0;
    resultTC = simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, false, overrideDropRate, 300, false, false);
    assertNotNull(resultTC);
    clusterGenerationId++;
    //simulate the increase of certain error (connect exception, closedChannelException) rate will cause degradation.
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, true, 0.0, 300, false, true);
    //switching to call dropping strategy
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, false, 0.0, 300, false, true);
    //continue the degradation
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, true, 0.0, 300, false, true);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, false, 0.0, 300, false, true);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, true, 0.0, 300, false, true);
    //now let's remove all the error and see how the cluster recover but we have to wait until next round because
    //this round is CALL_DROP strategy
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 1, false, 0.0, 300, false, false);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, true, 0.0, 300, false, false);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 39, false, 0.0, 300, false, false);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, true, 0.0, 300, false, false);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 80, false, 0.0, 300, false, false);
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, true, 0.0, 300, false, false);
    //make sure if we have error that is not from CONNECT_EXCEPTION or CLOSED_CHANNEL_EXCEPTION we don't degrade
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, false, 0.0, 300, true, false);
    //since there's no change in hash ring due to error NOT of CONNECT_EXCEPTION or CLOSED_CHANNEL_EXCEPTION,
    //the strategy won't change to CALL_DROPPING
    simulateAndTestOneInterval(timeInterval, clock, qps, clients, adapter, clusterGenerationId, 100, false, 0.0, 300, true, false);
}

Example 87 with LinkedList

use of java.util.LinkedList in project JsonPath by jayway.

the class JsonContext method read.

@Override
public <T> T read(String path, Predicate... filters) {
    notEmpty(path, "path can not be null or empty");
    Cache cache = CacheProvider.getCache();
    path = path.trim();
    LinkedList filterStack = new LinkedList<Predicate>(asList(filters));
    String cacheKey = Utils.concat(path, filterStack.toString());
    JsonPath jsonPath = cache.get(cacheKey);
    if (jsonPath != null) {
        return read(jsonPath);
    } else {
        jsonPath = compile(path, filters);
        cache.put(cacheKey, jsonPath);
        return read(jsonPath);
    }
}

Example 88 with LinkedList

use of java.util.LinkedList in project Smack by igniterealtime.

the class DNSUtil method sortSRVRecords.

/**
     * Sort a given list of SRVRecords as described in RFC 2782
     * Note that we follow the RFC with one exception. In a group of the same priority, only the first entry
     * is calculated by random. The others are ore simply ordered by their priority.
     * 
     * @param records
     * @return the list of resolved HostAddresses
     */
private static List<HostAddress> sortSRVRecords(List<SRVRecord> records) {
    // (the root domain), abort."
    if (records.size() == 1 && records.get(0).getFQDN().equals("."))
        return Collections.emptyList();
    // sorting the records improves the performance of the bisection later
    Collections.sort(records);
    // create the priority buckets
    SortedMap<Integer, List<SRVRecord>> buckets = new TreeMap<Integer, List<SRVRecord>>();
    for (SRVRecord r : records) {
        Integer priority = r.getPriority();
        List<SRVRecord> bucket = buckets.get(priority);
        // create the list of SRVRecords if it doesn't exist
        if (bucket == null) {
            bucket = new LinkedList<SRVRecord>();
            buckets.put(priority, bucket);
        }
        bucket.add(r);
    }
    List<HostAddress> res = new ArrayList<HostAddress>(records.size());
    for (Integer priority : buckets.keySet()) {
        List<SRVRecord> bucket = buckets.get(priority);
        int bucketSize;
        while ((bucketSize = bucket.size()) > 0) {
            int[] totals = new int[bucketSize];
            int running_total = 0;
            int count = 0;
            int zeroWeight = 1;
            for (SRVRecord r : bucket) {
                if (r.getWeight() > 0) {
                    zeroWeight = 0;
                    break;
                }
            }
            for (SRVRecord r : bucket) {
                running_total += (r.getWeight() + zeroWeight);
                totals[count] = running_total;
                count++;
            }
            int selectedPos;
            if (running_total == 0) {
                // If running total is 0, then all weights in this priority
                // group are 0. So we simply select one of the weights randomly
                // as the other 'normal' algorithm is unable to handle this case
                selectedPos = (int) (Math.random() * bucketSize);
            } else {
                double rnd = Math.random() * running_total;
                selectedPos = bisect(totals, rnd);
            }
            // add the SRVRecord that was randomly chosen on it's weight
            // to the start of the result list
            SRVRecord chosenSRVRecord = bucket.remove(selectedPos);
            res.add(chosenSRVRecord);
        }
    }
    return res;
}

Example 89 with LinkedList

use of java.util.LinkedList in project Smack by igniterealtime.

the class SmackExceptionTest method testConnectionException.

@Test
public void testConnectionException() throws UnknownHostException {
    List<HostAddress> failedAddresses = new LinkedList<HostAddress>();
    String host = "foo.bar.example";
    InetAddress inetAddress = InetAddress.getByAddress(host, new byte[] { 0, 0, 0, 0 });
    List<InetAddress> inetAddresses = Collections.singletonList(inetAddress);
    HostAddress hostAddress = new HostAddress(host, 1234, inetAddresses);
    hostAddress.setException(new Exception("Failed for some reason"));
    failedAddresses.add(hostAddress);
    host = "barz.example";
    inetAddress = InetAddress.getByAddress(host, new byte[] { 0, 0, 0, 0 });
    inetAddresses = Collections.singletonList(inetAddress);
    hostAddress = new HostAddress(host, 5678, inetAddresses);
    hostAddress.setException(new Exception("Failed for some other reason"));
    failedAddresses.add(hostAddress);
    ConnectionException connectionException = ConnectionException.from(failedAddresses);
    String message = connectionException.getMessage();
    assertEquals("The following addresses failed: 'foo.bar.example:1234' failed because: java.lang.Exception: Failed for some reason, 'barz.example:5678' failed because: java.lang.Exception: Failed for some other reason", message);
}

Example 90 with LinkedList

use of java.util.LinkedList in project Openfire by igniterealtime.

the class MucMamPersistenceManager method findMessages.

@Override
public Collection<ArchivedMessage> findMessages(Date startDate, Date endDate, String owner, String with, XmppResultSet xmppResultSet) {
    JID mucRoom = new JID(owner);
    MultiUserChatManager manager = XMPPServer.getInstance().getMultiUserChatManager();
    MultiUserChatService service = manager.getMultiUserChatService(mucRoom);
    MUCRoom room = service.getChatRoom(mucRoom.getNode());
    Connection connection = null;
    PreparedStatement pstmt = null;
    ResultSet rs = null;
    // If logging isn't enabled, do nothing.
    if (!room.isLogEnabled())
        return null;
    List<ArchivedMessage> msgs = new LinkedList<>();
    if (startDate == null) {
        startDate = new Date(0L);
    }
    if (endDate == null) {
        endDate = new Date();
    }
    int max = xmppResultSet.getMax();
    // TODO: Suppress this, since we don't yet have requestor information for access control.
    with = null;
    try {
        connection = DbConnectionManager.getConnection();
        StringBuilder sql = new StringBuilder(LOAD_HISTORY);
        if (with != null) {
            sql.append(WHERE_SENDER);
        }
        if (xmppResultSet.getAfter() != null) {
            sql.append(WHERE_AFTER);
        }
        if (xmppResultSet.getBefore() != null) {
            sql.append(WHERE_BEFORE);
        }
        sql.append(ORDER_BY);
        pstmt = connection.prepareStatement(sql.toString());
        pstmt.setString(1, StringUtils.dateToMillis(startDate));
        pstmt.setString(2, StringUtils.dateToMillis(endDate));
        pstmt.setLong(3, room.getID());
        int pos = 3;
        if (with != null) {
            pstmt.setString(++pos, with);
        }
        if (xmppResultSet.getAfter() != null) {
            pstmt.setLong(++pos, xmppResultSet.getAfter());
        }
        if (xmppResultSet.getBefore() != null) {
            pstmt.setLong(++pos, xmppResultSet.getBefore());
        }
        rs = pstmt.executeQuery();
        while (rs.next()) {
            String senderJID = rs.getString(1);
            String nickname = rs.getString(2);
            Date sentDate = new Date(Long.parseLong(rs.getString(3).trim()));
            String subject = rs.getString(4);
            String body = rs.getString(5);
            String stanza = rs.getString(6);
            long id = rs.getLong(7);
            if (stanza == null) {
                Message message = new Message();
                message.setType(Message.Type.groupchat);
                message.setSubject(subject);
                message.setBody(body);
                // Set the sender of the message
                if (nickname != null && nickname.trim().length() > 0) {
                    JID roomJID = room.getRole().getRoleAddress();
                    // Recreate the sender address based on the nickname and room's JID
                    message.setFrom(new JID(roomJID.getNode(), roomJID.getDomain(), nickname, true));
                } else {
                    // Set the room as the sender of the message
                    message.setFrom(room.getRole().getRoleAddress());
                }
                stanza = message.toString();
            }
            ArchivedMessage archivedMessage = new ArchivedMessage(sentDate, ArchivedMessage.Direction.from, null, null);
            archivedMessage.setStanza(stanza);
            archivedMessage.setId(id);
            msgs.add(archivedMessage);
        }
    } catch (SQLException e) {
        Log.error("SQL failure during MAM-MUC: ", e);
    } finally {
        DbConnectionManager.closeConnection(rs, pstmt, connection);
    }
    // TODO - Not great, really should be done by suitable LIMIT stuff.
    // Would need to reverse ordering in some cases and then reverse results.
    boolean complete = true;
    xmppResultSet.setCount(msgs.size());
    while (msgs.size() > max) {
        msgs.remove(msgs.size() - 1);
        complete = false;
    }
    xmppResultSet.setComplete(complete);
    if (msgs.size() > 0) {
        xmppResultSet.setFirst(msgs.get(0).getId());
        if (msgs.size() > 1) {
            xmppResultSet.setLast(msgs.get(msgs.size() - 1).getId());
        }
    }
    return msgs;
}