public static void main(String[] args) throws Exception {
System.out.println("Starting Cache Client...");
int bucket;
List<CacheServiceInterface> serverlist = new ArrayList<CacheServiceInterface>();
serverlist.add(new DistributedCacheService("http://localhost:3000"));
serverlist.add(new DistributedCacheService("http://localhost:3001"));
serverlist.add(new DistributedCacheService("http://localhost:3002"));
CharSequence val;
for (int key = 1; key <= 10; key++) {
val = generateRandomChar();
bucket =
Hashing.consistentHash(
Hashing.md5().hashString(Integer.toString(key)), serverlist.size());
serverlist.get(bucket).put(key, val.toString());
System.out.println("put (key " + key + " and value " + val + ")" + " in bucket " + bucket);
}
for (int key = 1; key <= 10; key++) {
bucket =
Hashing.consistentHash(
Hashing.md5().hashString(Integer.toString(key)), serverlist.size());
System.out.println(
"get (key "
+ key
+ " and value "
+ serverlist.get(bucket).get(key)
+ ")"
+ "from bucket "
+ bucket);
}
System.out.println("Exiting Cache Client...");
}
@Test
public void mappedServersTest() {
Map<Integer, String> servers = new HashMap<>();
servers.put(0, "server0");
servers.put(1, "server1");
HashFunction md5 = Hashing.md5();
List<PartitionEntry> triggers = generateTriggers(3, 1000);
Map<Integer, String> newPartition;
Map<Integer, String> oldPartition;
print("initial - test 2 servers " + servers.toString());
newPartition = new HashMap<>();
for (PartitionEntry trigger : triggers) {
newPartition.put(
trigger.hashCode(),
servers.get(Hashing.consistentHash(md5.hashInt(trigger.hashCode()), 2)));
}
for (int buckets = 3; buckets < 10; buckets++) {
servers.put(buckets - 1, "server" + (buckets - 1));
print("test " + buckets + " servers " + servers.toString());
oldPartition = newPartition;
newPartition = new HashMap<>();
for (PartitionEntry trigger : triggers) {
newPartition.put(
trigger.hashCode(),
servers.get(Hashing.consistentHash(md5.hashInt(trigger.hashCode()), buckets)));
}
int changes = comparePartitions(oldPartition, newPartition);
print(
"Changes from "
+ (buckets - 1)
+ " to "
+ buckets
+ " servers: "
+ changes
+ " of "
+ oldPartition.size());
print("" + (((float) changes / (float) oldPartition.size()) * 100) + " % moved");
print(
"K("
+ oldPartition.size()
+ ")/n("
+ buckets
+ "): "
+ ((float) oldPartition.size() / (float) buckets));
}
}
public static void main(String[] args) throws Exception {
System.out.println("Starting Cache Client...");
String[] value = {
"0",
"Ferrari 250 GTO",
"Ferrari 250 Testa Rossa",
"Jaguar XJ13",
"Mercedes-Benz SLR McLaren",
"Ferrari 330 P4",
"Maybach Exelero",
"Rolls-Royce Hyperion",
"Lamborghini Veneno",
"Zenvo ST1",
"Audi Le Mans Concept",
" McLaren X-1 Concept",
"Koenigsegg CCXR Trevita"
};
List<DistributedCacheService> server = new ArrayList<DistributedCacheService>();
server.add(new DistributedCacheService("http://localhost:3000"));
server.add(new DistributedCacheService("http://localhost:3001"));
server.add(new DistributedCacheService("http://localhost:3002"));
System.out.println(" ----------------------Putting values to server------------------");
for (int putkey = 1; putkey <= 12; putkey++) {
int bucket =
Hashing.consistentHash(Hashing.md5().hashString(Integer.toString(putkey)), server.size());
server.get(bucket).put(putkey, value[putkey]);
System.out.println(
"The key value pair "
+ putkey
+ "-"
+ value[putkey]
+ " is assigned to server "
+ bucket);
}
System.out.println(" ----------------------Getting values from server------------------");
for (int getkey = 1; getkey <= 12; getkey++) {
int bucket =
Hashing.consistentHash(Hashing.md5().hashString(Integer.toString(getkey)), server.size());
System.out.println(
"The key value pair "
+ getkey
+ "-"
+ server.get(bucket).get(getkey)
+ " is received to server "
+ bucket);
}
System.out.println(" ------------------------------Terminated---------------------------");
}
public void testConsistentHash_outOfRange() {
try {
Hashing.consistentHash(5L, 0);
fail();
} catch (IllegalArgumentException expected) {
}
}
/**
* * Estimates whether the item provided as parameter is already part of the RLBS Bloom Filter,
* that is, if the item is a duplicate of a previously seen item. If the item is found to be
* duplicate, returns true, otherwise false. False Positives and False Negatives can occur with a
* low probability
*
* @param strItem item to be checked, in order to estimate if it was previously detected
* @return True if the item has been previously detected, false otherwise (with certain a false
* positive/negative rate)
*/
public boolean checkDuplicate(String strItem) {
// Hash the item through the k hashing functions
int[] arrItemHashings = new int[this.k];
boolean isDuplicate = true;
// Hash the item through the k hash functions and determine whether is duplicate
for (int i = 0; i < this.k; i++) {
// Generate the hashing index of the item for bit array #i
arrItemHashings[i] =
Hashing.consistentHash(
this.arrHashFunctions[i].hashUnencodedChars(strItem), this.bitSetSize);
// Check if the corresponding bit is set to 0, which is enough to regard the item as distinct
isDuplicate = isDuplicate && this.arrBitSets[i].get(arrItemHashings[i]);
}
logger.debug(
"Item: {} encoded, is duplicate: {}. Positions: {}", strItem, isDuplicate, arrItemHashings);
if (!isDuplicate) {
Random randGen = new Random();
BitSet bitArray = null;
BigDecimal curProbReset = null;
// The item was estimated to be distinct, randomly balance the load on each bit array
for (int j = 0; j < this.k; j++) {
// Determine how many bits are set in the array
bitArray = this.arrBitSets[j];
// Compute the probability of reseting a bit of the current bit array, as L(i)/s
curProbReset =
(new BigDecimal(bitArray.cardinality()))
.divide(BigDecimal.valueOf(this.bitSetSize), RoundingMode.HALF_EVEN);
// Reset a random bit of the bit array, with probability curProbReset
if (randGen.nextDouble() <= curProbReset.doubleValue()) {
// Select a random bit position to be reset...
int randPosToReset = randGen.nextInt(this.bitSetSize);
bitArray.clear(randPosToReset);
logger.debug(
"Load balancing BF{}. Resetting item at position {} will be reset (reset prob. {})",
j,
randPosToReset,
curProbReset);
} else {
logger.debug(
"Load balancing BF{}. Randomly chose not to reset any position (reset prob. {})",
j,
curProbReset);
}
// Set the bit the item was mapped to by the hashing function
bitArray.set(arrItemHashings[j]);
}
}
return isDuplicate;
}
private void countRemaps(long h, AtomicLongMap<Integer> map) {
int last = 0;
for (int shards = 2; shards <= MAX_SHARDS; shards++) {
int chosen = Hashing.consistentHash(h, shards);
if (chosen != last) {
map.incrementAndGet(shards);
last = chosen;
}
}
}
private void checkConsistentHashCorrectness(long hashCode) {
int last = 0;
for (int shards = 1; shards <= 100000; shards++) {
int b = Hashing.consistentHash(hashCode, shards);
if (b != last) {
assertEquals(shards - 1, b);
last = b;
}
}
}
@Override
public Integer calculate(String columnValue) {
try {
long targetTime = new SimpleDateFormat(dateFormat).parse(columnValue).getTime();
int targetPartition = (int) ((targetTime - beginDate) / partionTime);
int innerIndex = Hashing.consistentHash(targetTime, intGroupPartionSize);
return targetPartition * intGroupPartionSize + innerIndex;
} catch (ParseException e) {
throw new IllegalArgumentException(e);
}
}
@Override
public AsyncLeaderElector newAsyncLeaderElector(String name) {
checkNotNull(name);
Map<PartitionId, AsyncLeaderElector> leaderElectors =
Maps.transformValues(members, partition -> partition.newAsyncLeaderElector(name));
Hasher<String> hasher =
topic -> {
long hashCode = HashCode.fromBytes(topic.getBytes(Charsets.UTF_8)).asLong();
return sortedMemberPartitionIds.get(Hashing.consistentHash(hashCode, members.size()));
};
return new PartitionedAsyncLeaderElector(name, leaderElectors, hasher);
}
@Override
public <K, V> AsyncConsistentMap<K, V> newAsyncConsistentMap(String name, Serializer serializer) {
checkNotNull(name);
checkNotNull(serializer);
Map<PartitionId, AsyncConsistentMap<K, V>> maps =
Maps.transformValues(
members, partition -> partition.newAsyncConsistentMap(name, serializer));
Hasher<K> hasher =
key -> {
long hashCode =
HashCode.fromBytes(Bytes.ensureCapacity(serializer.encode(key), 8, 0)).asLong();
return sortedMemberPartitionIds.get(Hashing.consistentHash(hashCode, members.size()));
};
return new PartitionedAsyncConsistentMap<>(name, maps, hasher);
}
@Test
public void consistentHashTest() {
HashFunction md5 = Hashing.md5();
List<PartitionEntry> triggers = generateTriggers(3, 1000);
Map<Integer, Integer> newPartition;
Map<Integer, Integer> oldPartition;
print("initial - test 2 servers");
newPartition = new HashMap<>();
for (PartitionEntry trigger : triggers) {
newPartition.put(
trigger.hashCode(), Hashing.consistentHash(md5.hashInt(trigger.hashCode()), 2));
}
for (int buckets = 3; buckets < 10; buckets++) {
print("test " + buckets + " servers");
oldPartition = newPartition;
newPartition = new HashMap<>();
for (PartitionEntry trigger : triggers) {
newPartition.put(
trigger.hashCode(), Hashing.consistentHash(md5.hashInt(trigger.hashCode()), buckets));
}
int changes = comparePartitions(oldPartition, newPartition);
print(
"Changes from "
+ (buckets - 1)
+ " to "
+ buckets
+ " servers: "
+ changes
+ " of "
+ oldPartition.size());
print("" + (((float) changes / (float) oldPartition.size()) * 100) + " % moved");
print(
"K("
+ oldPartition.size()
+ ")/n("
+ buckets
+ "): "
+ ((float) oldPartition.size() / (float) buckets));
}
for (int buckets = 10; buckets > 3; buckets--) {
print("test " + buckets + " servers");
oldPartition = newPartition;
newPartition = new HashMap<>();
for (PartitionEntry trigger : triggers) {
newPartition.put(
trigger.hashCode(), Hashing.consistentHash(md5.hashInt(trigger.hashCode()), buckets));
}
int changes = comparePartitions(oldPartition, newPartition);
print(
"Changes from "
+ (buckets)
+ " to "
+ (buckets - 1)
+ " servers: "
+ changes
+ " of "
+ oldPartition.size());
print("" + (((float) changes / (float) oldPartition.size()) * 100) + " % moved");
print(
"K("
+ oldPartition.size()
+ ")/n("
+ buckets
+ "): "
+ ((float) oldPartition.size() / (float) buckets));
}
}
/**
* Returns the {@code DistributedPrimitiveCreator} to use for hosting a primitive.
*
* @param name primitive name
* @return primitive creator
*/
private DistributedPrimitiveCreator getCreator(String name) {
int index = Hashing.consistentHash(name.hashCode(), members.size());
return members.get(sortedMemberPartitionIds.get(index));
}
public void checkSameResult(HashCode hashCode, long equivLong) {
assertEquals(Hashing.consistentHash(equivLong, 5555), Hashing.consistentHash(hashCode, 5555));
}
