In this section, we list the changes what users should take into account before upgrading to latest Hazelcast from earlier versions.
Map<Integer, String> customers = Hazelcast.getMap( "customers" );
with
HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
// or if you already started an instance named "instance1"
// HazelcastInstance hazelcastInstance = Hazelcast.getHazelcastInstanceByName( "instance1" );
Map<Integer, String> customers = hazelcastInstance.getMap( "customers" );
Removal of lite members: With 3.0 there will be no member type as lite member. As 3.0 clients are smart client that they know in which node the data is located, you can replace your lite members with native clients.
Renaming "instance" to "distributed object": Before 3.0 there was a confusion for the term "instance". It was used for both the cluster members and the distributed objects (map, queue, topic, etc. instances). Starting 3.0, the term instance will be only used for Hazelcast instances, namely cluster members. We will use the term "distributed object" for map, queue, etc. instances. So you should replace the related methods with the new renamed ones. As 3.0 clients are smart client that they know in which node the data is located, you can replace your lite members with native clients.
public static void main( String[] args ) throws InterruptedException {
HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
IMap map = hazelcastInstance.getMap( "test" );
Collection<Instance> instances = hazelcastInstance.getInstances();
for ( Instance instance : instances ) {
if ( instance.getInstanceType() == Instance.InstanceType.MAP ) {
System.out.println( "There is a map with name: " + instance.getId() );
}
}
}
with
public static void main( String[] args ) throws InterruptedException {
HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
IMap map = hz.getMap( "test" );
Collection<DistributedObject> objects = hazelcastInstance.getDistributedObjects();
for ( DistributedObject object : objects ) {
if ( distributedObject instanceof IMap ) {
System.out.println( "There is a map with name: " + object.getName() );
}
}
}
com.hazelcast.core
from com.hazelcast.partition
.removeListener
methods was taking the Listener object as parameter. But, it causes confusion as same listener object may be used as parameter for different listener registrations. So we have changed the listener API. addListener
methods return you an unique ID and you can remove listener by using this ID. So you should do following replacement if needed:IMap map = hazelcastInstance.getMap( "map" );
map.addEntryListener( listener, true );
map.removeEntryListener( listener );
with
IMap map = hazelcastInstance.getMap( "map" );
String listenerId = map.addEntryListener( listener, true );
map.removeEntryListener( listenerId );
tryRemove(K key, long timeout, TimeUnit timeunit)
returns boolean indicating whether operation is successful.tryLockAndGet(K key, long time, TimeUnit timeunit)
is removed.putAndUnlock(K key, V value)
is removed.lockMap(long time, TimeUnit timeunit)
and unlockMap()
are removed.getMapEntry(K key)
is renamed as getEntryView(K key)
. The returned object's type, MapEntry class is renamed as EntryView.<merge-policy>com.hazelcast.map.merge.PassThroughMergePolicy</merge-policy>
Also MergePolicy interface has been renamed to MapMergePolicy and also returning null from the implemented merge()
method causes the existing entry to be removed.
IQueue
is configured. With Hazelcast 3.0 there will not be backing map configuration for queue. Settings like backup count will be directly configured on queue config. For queue configuration details, please see Queue.pause()
, resume()
, restart()
methods have been removed.AtomicNumber
class has been renamed to IAtomicLong
.await()
operation has been removed. We expect users to use await()
method with timeout parameters.ISemaphore
has been substantially changed. attach()
, detach()
methods have been removed.