Hazelcast Jet Sources.mapJournal metodu

Örnek

Şöyle yaparız

IMap<Long, String> myMap = ...;
Pipeline p = Pipeline.create();
p.readFrom(Sources.mapJournal(myMap, START_FROM_CURRENT))
  .withoutTimestamps()
  .writeTo(Sinks.jdbc("%some update query%", () -> {
    BaseDataSource dataSource = new PGXADataSource();
    dataSource.setUrl("jdbc:postgresql://localhost:5432/my_db");
    dataSource.setUser("postgres");
    dataSource.setPassword("postgres");
    dataSource.setDatabaseName("my_db");
    return dataSource;
  }, (stmt, record) -> {
    // fill query params and execute                         
}));

Hazelcast Jet CDC CdcSinks Sınıfı

Giriş

Şu satırı dahil ederiz 

import com.hazelcast.jet.cdc.CdcSinks;

CDC ile yakalanan değişiklikleri bir sink nesnesine yazar

map metodu

Örnek

Şöyle yaparız

StreamSource<ChangeRecord> theDataBase = ...;,
IMap<Long, String> myMap = ...;

var pipeline = Pipeline.create();
pipeline.readFrom(theDataBase)
  .withoutTimestamps()
  .writeTo(CdcSinks.map(myMap, 
    record -> Long.parseLong(record.key().toMap().get("id").toString()), 
    record -> record.value().toJson()));

record nesnesi com.hazelcast.jet.cdc.ChangeRecord tipinden. key() metodu ile 

com.hazelcast.jet.cdc.RecordPart nesnesi elde edilir. toMap() çağrısı ile JSON nesnesi map haline getirilir

Hazelcast Jet QueryResultProducer Arayüzü

Giriş
Şu satırı dahil ederiz 

import com.hazelcast.jet.sql.impl.QueryResultProducer;

SQL içindeki LIMIT N şeklinde sonuçlar burada gerçekleşir

Hazelcast Jet PipelineImpl Sınıfı

Giriş
Şu satırı dahil ederiz 

import com.hazelcast.jet.impl.pipeline.PipelineImpl;

Pipeline arayüzünden kalıtır. readFrom(), writeTo() gibi işlemler adjacencyMap içindedir. Bu map içindeki nesneler Serializable olmak zorunda

Kod şöyle

public class PipelineImpl implements Pipeline {

  private static final long serialVersionUID = 1L;

  private final Map<Transform, List<Transform>> adjacencyMap = new LinkedHashMap<>();
  private final Map<String, File> attachedFiles = new HashMap<>();
  private boolean preserveOrder;
  ...
}

Hazelcast Jet Sources.remoteMap

Giriş

İmzası şöyle

public static <K, V> BatchSource<Entry<K, V>> remoteMap(
  String mapName,
  ClientConfig clientConfig
)

public static <T, K, V> BatchSource<T> remoteMap(
  String mapName,
  ClientConfig clientConfig,
  Predicate<K, V> predicate,
  Projection<? super Entry<K, V>, ? extends T> projection
)

public static <K, V> BatchSource<Entry<K, V>> remoteMap(
  String mapName,
  DataConnectionRef dataConnectionRef
)

public static <T, K, V> BatchSource<T> remoteMap(
  String mapName,
  DataConnectionRef dataConnectionRef,
  Predicate<K, V> predicate,
  Projection<? super Entry<K, V>, ? extends T> projection
)

Altta şöyle yapar

1. RemoteMapQueryReaderFunction : ReadMapOrCacheP : com.hazelcast.jet.impl.connector.Reader ile okuma yapar

2. RemoteMapReaderFunction : RemoteMapReader : Entry<Data, Data> olarak okur

Hazelcast Discovery SPI MemberAddressProvider Arayüzü

Giriş

Şu satırı dahil ederiz

import com.hazelcast.spi.MemberAddressProvider;

Açıklaması şöyle

This class tries to work out which interface to choose as the address of the member

hazelcast.xml NearCache Ayarları

Örnek

Şöyle yaparız

hazelcast-client:
  ...
  near-cache:
    stargatedemo-internal:
      in-memory-format: BINARY
      invalidate-on-change: true
      eviction:
        eviction-policy: LRU
        max-size-policy: ENTRY_COUNT
        size: 50000

HazelcastAPI ClientConfigXmlGenerator Sınıfı

Giriş

Şu satırı dahil ederiz

import com.hazelcast.client.config.ClientConfigXmlGenerator;

ClientConfig nesnesini XML'e çevirir

Örnek

Şöyle yaparız

ClientConfig config = ...;
String str = ClientConfigXmlGenerator.generate(config, 2);


try (InputStream is = new ByteArrayInputStream(str.getBytes(StandardCharsets.UTF_8))) {
  // CLASS LOADER IS SET by XmlClientConfigBuilder
  ClientConfig newConfig = new XmlClientConfigBuilder(is).build();
}

HazelcastExecutor IExecutorService Arayüzü - Callable

Giriş

Şunlar kullanılabilir.

submitToAllMembers //Tüm üyelere gönder
submitToKeyOwner   //Belirtilen key sahibi üyeye gönder
submitToMember     //Belirtilen üyeye gönder
submitToMembers    //Belirtilen üyelere gönder

İmzalar şöyle

Future<T> submit(Callable<T> task, MemberSelector memberSelector);
void submit(Callable<T> task,ExecutionCallback<T> callback);
void submit(Callable<T> task, MemberSelector memberSelector,
            ExecutionCallback<T> callback);

Future<T> submitToKeyOwner(Callable<T> task, Object key);
void submitToKeyOwner(Callable<T> task, Object key,
                      ExecutionCallback<T> callback);

Future<T> submitToMember(Callable<T> task, Member member);
void submitToMember(Callable<T> task, Member member,
                    ExecutionCallback<T> callback);

Map<Member, Future<T>> submitToMembers(Callable<T> task,
                                       Collection<Member> members);
Map<Member, Future<T>> submitToMembers(Callable<T> task,
                                       MemberSelector memberSelector);
void submitToMembers(Callable<T> task,Collection<Member> members,
                     MultiExecutionCallback callback);

void submitToMembers(Callable<T> task,
                     MemberSelector memberSelector,
                     MultiExecutionCallback callback);

Map<Member, Future<T>> submitToAllMembers(Callable<T> task);
void submitToAllMembers(Callable<T> task,
                        MultiExecutionCallback callback);

submit metodu

Örnek

Şöyle yaparız

public class DemoTask implements Callable<Map<String, Object>>, Serializable { 
  ... 
  @Override 
  public Map<String, Object> call() throws Exception { 
    ...
    Map<String, Object> result = new HashMap<>(); 
    result.put("...", "..."
    return result; 
  } 
} 

DemoTask task = new DemoTask(); 
executorService.submit(task, new ExecutionCallback<Map<String, Object>>() { 
  @Override
  public void onResponse(Map<String, Object> incomingResponse) { 
   ...
  } 
  @Override  
  public void onFailure(Throwable t) { 
    ...
  } 
});

HazelcastAPI ExtendedMapEntry Arayüzü

Giriş

Şu satırı dahil ederiz

import com.hazelcast.map.ExtendedMapEntry;

setValue metodu

Örnek

Şöyle yaparız

class IncrementWithOptionalTtl implements EntryProcessor<Integer, Integer, Void> {
  private final long ttlSeconds;
   
  public IncrementWithOptionalTtl(long ttlSeconds) {
    this.ttlSeconds = ttlSeconds;
  }
 
  @Override
  public Void process(Map.Entry<Integer, Integer> e) {
    ExtendedMapEntry<Integer, Integer> entry = (ExtendedMapEntry<Integer, Integer>) e;
    int newValue = entry.getValue() + 1;
    if (ttlSeconds > 0) {
      entry.setValue(newValue, ttlSeconds, TimeUnit.SECONDS);
    } else {
      entry.setValue(newValue);
    }
    return null;
  }
}

Örnek

Şöyle yaparız

public Object process(Entry entry) {
  Object oldValue = entry.getValue();
  ExtendedMapEntry extendedMapEntry = (com.hazelcast.map.ExtendedMapEntry) entry;
  extendedMapEntry.setValue(oldValue, 30, TimeUnit.SECONDS);
  return oldValue;
}

Hazelcast SQL GENERATE_STREAM + IMap JOIN

Örnek

Şöyle bir VIEW yaratırız.

CREATE OR REPLACE VIEW orders AS
  SELECT id,

       CASE WHEN orderRand BETWEEN 0 AND 0.2 THEN '11001'
            WHEN orderRand BETWEEN 0.2 AND 0.4 THEN '11002'
            WHEN orderRand BETWEEN 0.4 AND 0.6 THEN '11003'
            WHEN orderRand BETWEEN 0.6 AND 0.8 THEN '11004'
            ELSE '11005'
       END as cust_id,

       CASE WHEN orderRand*1.5 BETWEEN 0 AND 0.25 THEN '501'
            WHEN orderRand*1.5 BETWEEN 0.25 AND 0.5 THEN '502'
            WHEN orderRand*1.5 BETWEEN 0.5 AND 0.75 THEN '503'
            ELSE '504'
       END as item_num,

       CASE WHEN orderRand*.66 BETWEEN 0 AND .25 THEN CAST(1 AS SMALLINT)
            WHEN orderRand*.66 BETWEEN .25 AND .5 THEN CAST(2 AS SMALLINT)
            ELSE CAST(3 AS SMALLINT)
       END as quantity,
       order_ts
FROM
    (SELECT v as id,
           RAND(v*v*v) as orderRand,
           TO_TIMESTAMP_TZ(v*10 + 1645484400000) as order_ts
     FROM TABLE(generate_stream(7)));

Şöyle bir customers IMap yaratırız ve doldururuz

CREATE or REPLACE MAPPING customers (
     __key BIGINT,
     cust_id VARCHAR,
     last_name VARCHAR,
     first_name VARCHAR,
     address1 VARCHAR,
     address2 VARCHAR,
     phone VARCHAR )
TYPE IMap
OPTIONS (
'keyFormat'='bigint',
'valueFormat'='json-flat');

// Populate the customers map with data.

SINK INTO customers VALUES
(1,'11001', 'Smith', 'John', '123 Main St', 'Ames, IA 50012', '515-555-1212'),
(2,'11002', 'Li', 'Guo', '456 Powell St', 'San Francisco, CA 94108', '415-555-1212'),
(3,'11003', 'Ivanov', 'Sergei', '999 Brighton Blvd', 'New York, NY 11235','212-555-1212'),
(4,'11004', 'Mohammed', 'Ibrahim', '42 Elm St', 'Dearborn, MI 48126', '313-555-1212'),
(5,'11005', 'Patel', 'Ram', '5151 Market St', 'Trenton, NJ 08615', '609-555-1212');

Şöyle bir inventory IMap yaratırız ve doldururuz

CREATE or REPLACE MAPPING inventory (
     __key BIGINT,
     item_num VARCHAR,
     unit_price DECIMAL,
     quantity SMALLINT)
TYPE IMap
OPTIONS (
'keyFormat'='bigint',
'valueFormat'='json-flat');
SQL
Populate the inventory database.

SINK INTO inventory VALUES
(1, '501', 1.99, 500),
(2, '502', 3.99, 500),
(3, '503', 5.99, 500),
(4, '504', 7.99, 500);

 Hedef IMap'i yaratırız

CREATE OR REPLACE MAPPING PickOrder (
   __key BIGINT,
   ts TIMESTAMP,
  item_num VARCHAR,
  quantity SMALLINT,
  cust_id VARCHAR,
  last_name VARCHAR,
  first_name VARCHAR,
  address1 VARCHAR,
  address2 VARCHAR,
  phone VARCHAR)
TYPE IMap
OPTIONS (
'keyFormat'='bigint',
'valueFormat'='json-flat');

Bunu dolduracak iş için şöyle yaparız. Gelen order ile ilişkili customer ve inventory bulunur

CREATE JOB PickOrder AS
SINK INTO PickOrder
     SELECT
          ord.id AS __key,
          ord.order_ts AS ts,
          ord.item_num AS item_num,
          ord.quantity AS quantity,
          ord.cust_id AS cust_id,
          cust.last_name AS last_name,
          cust.first_name AS first_name,
          cust.address1 AS address1,
          cust.address2 AS address2,
          cust.phone AS phone
     FROM orders AS ord
     JOIN customers AS cust ON ord.cust_id = cust.cust_id
     JOIN inventory ON ord.item_num = inventory.item_num
     WHERE ord.quantity < inventory.quantity;

HazelcastAPI DefaultWriteBehindProcessor Sınıfı

Giriş

Şu satırı dahil ederiz

import com.hazelcast.map.impl.mapstore.DefaultWriteBehindProcessor;

Kalıtım şöyle

WriteBehindProcessor

  AbstractWriteBehindProcessor

    DefaultWriteBehindProcessor

Bu sınıfın etkin olması için şöyle yaparız. Yani setWriteDelaySeconds() çağrısı gerekir

MapStoreConfig mapStoreConfig = new MapStoreConfig();
mapStoreConfig
  .setWriteCoalescing (true)
  .setImplementation(myMapStore)
  .setWriteDelaySeconds(10) 
  .setWriteBatchSize(1_000)

config.getMapConfig(...).setMapStoreConfig(mapStoreConfig)

process metodu

İmzası şöyle. StoreWorker tarafından çağrılır

@Override
public Map<Integer, List<DelayedEntry>> process(List<DelayedEntry> delayedEntries)

HazelcastExecutor DurableExecutorService Arayüzü

Giriş

Şu satırı dahil ederiz

import com.hazelcast.durableexecutor.DurableExecutorService;

Eğer durability atandıysa, member kapanırsa bile çalışmakta olan edilen iş kaybolmaz. Başka bir member'da tekrar başlatılır

Örnek

Şöyle yaparız

Config config = new Config();
config.getDurableExecutorConfig("MyService").setDurability(2).setCapacity(200).setPoolSize(2);

HazelcastInstance hc = Hazelcast.newHazelcastInstance(config);
hc.getMap("MyMap").put("Key-1", "Value-1");

DurableExecutorService service = hc.getDurableExecutorService("MyService");
service.executeOnKeyOwner(new MyRunnable(), "Key-1"); com.hazelcast.durableexecutor.DurableExecutorService;aa. aa

hazelcast.xml - CP Subsytem Ayarları

Örnek

Şöyle yaparız

<hazelcast>
  <cp-subsystem>
   <!-- set cp-member-count with value 0 to run in unsafe mode -->
    <cp-member-count>3</cp-member-count>
    <!-- configuration options here -->
  </cp-subsystem>
</hazelcast>

HazelcastAPI Max Idle Seconds ve TTL

Max Idle Seconds - Belli Bir Süre Kullanılmazsa

Açıklaması şöyle

Max Idle time specifies the maximum time in seconds for an entry to stay idle in the map before it is evicted. An entry is considered idle if no get, put, or containsKey operation is performed on it.

Belli bir süre kullanılmayan nesneleri siler

1. MapConfig#setsetMaxIdleSeconds() metodu sağlar

2 . NearCacheConfig#setsetMaxIdleSeconds() metodu sağlar

TTL - Güncellemeden Sonraki En Fazla Süre

Açıklaması şöyle

TTL, or Time To Live, specifies the maximum lifespan of an entry from the moment it is created or updated. It controls how long an entry can exist in the map regardless of whether it's actively being used or not.

Session verisi gibi şeylerde işe yarar. Açıklaması şöyle. 

 Suppose you have an IMap for caching user sessions:

- If you set a Max Idle Time of 30 minutes, it means that if a user's session is not accessed (no read or update operations) for 30 minutes, the session entry will be automatically removed from the map, even if the user is still logged in.

- If you set a TTL of 1 hour for the same session entries, it means that regardless of whether the user is actively using the session or not, it will be automatically removed from the map after 1 hour from the time of creation.

1. Eğer kullanıcı 30 dakika etkin değilse Session silinir. Böylece bellekten tasarruf edilir.

2. Eğer kullanıcı etkin olsa bile 1 saat sonra Session silinir.  Böylece kullanıcı tekrar giriş yapmak zorunda. 

HazelcastSpringBoot Session Kullanımı

Giriş

Bir soru burada

Map İsmi

Map ismi şöyle

spring:session:sessions

Map yapısı 

Şöyle

key : sessionid

value : MapSession

ConsoleApp

Giriş

Açıklaması şöyle

The console tool enables you execute commands on the cluster. You can read or write on instances but first you should set namespace. For example if you have a map with name "mapCustomers". To get a customer with key "Jack" you should first set the namespace with command "ns mapCustomers". Then you can take the object by "m.get Jack"

Map Komutları

Açıklaması şöyle

m.put <key> <value>                  //puts an entry to the map
m.remove <key>                       //removes the entry of given key from the map
m.get <key>                          //returns the value of given key from the map
m.putmany <number> [<size>] [<index>]//puts indicated number of entries to the map ('key<i>':byte[<size>], <index>+(0..<number>)
m.removemany <number> [<index>]      //removes indicated number of entries from the map ('key<i>', <index>+(0..<number>)
     When using &x with m.putmany and m.removemany, each thread will get a different share of keys unless a start key <index> is specified
m.keys                               //iterates the keys of the map
m.values                             //iterates the values of the map
m.entries                            //iterates the entries of the map
m.iterator [remove]                  //iterates the keys of the map, remove if specified
m.size                               //size of the map
m.clear                              //clears the map
m.destroy                            //destroys the map
m.lock <key>                         //locks the key
m.tryLock <key>                      //tries to lock the key and returns immediately
m.tryLock <key> <time>               //tries to lock the key within given seconds
m.unlock <key>                       //unlocks the key

clear 

Örnek

Şöyle yaparız

default> ns spring:session:sessions
spring:session:sessions> m.clear

Örnek

Şöyle yapabiliriz

m.entries
m.size  

Örnek

Şöyle yaparız

> ns my-distributed-map

m.put "1" "John"

m.put "2" "Mary"

m.put "3" "Jane"

HazelcastClientAPI EvictionConfig Sınıfı

Giriş

Şu satırı dahil ederiz

import com.hazelcast.config.EvictionConfig;

EvictionConfig Nedir?

Bir veri yapısına üst sınır koymak içindir. Veri yapısı üst sınıra erişince hangi nesnelerin çıkarılacağını belirtir. Eğer EvictionConfig tanımlı değilse veri yapısı çok büyüyebilir

setMaxSizePolicy

setSize ile belirtilen değere ulaşınca kullanılacak eviction yöntemini belirtir

Örnek - ENTRY_COUNT

Şöyle yaparız. Veri yapısının eleman sayısı 100'ü geçince eviction başlar.

EvictionConfig evictionConfig = new EvictionConfig()
  .setMaxSizePolicy(MaxSizePolicy.ENTRY_COUNT)
  .setEvictionPolicy(EvictionPolicy.LRU)
  .setSize(100);

Not : IMap için kullanılamaz. Hata şöyle

IMap eviction config doesn't support max size policy `ENTRY_COUNT`.

Örnek - USED_HEAP_PERCENTAGE

Şöyle yaparız. Veri yapısı Heap'in yüzde 10'unu geçince eviction başlar.

EvictionConfig evictionConfig = new EvictionConfig()
  .setMaxSizePolicy(MaxSizePolicy.USED_HEAP_PERCENTAGE)
  .setEvictionPolicy(EvictionPolicy.LRU)
  .setSize(10);