Go to hazelcast.org/documentation

List

Hazelcast List is similar to Hazelcast Set, but Hazelcast List also allows duplicate elements.

  • Besides allowing duplicate elements, Hazelcast List preserves the order of elements.
  • Hazelcast List is a non-partitioned data structure where values and each backup are represented by their own single partition.
  • Hazelcast List cannot be scaled beyond the capacity of a single machine.
  • All items are copied to local and iteration occurs locally.

Getting a List and Putting Items

Use the HazelcastInstance getList method to get the list, then use the list put method to put items into the List.

import com.hazelcast.core.Hazelcast;
import java.util.List;
import java.util.Iterator;

HazelcastInstance hz = Hazelcast.newHazelcastInstance();

List<Price> list = hz.getList( "IBM-Quote-Frequency" );
list.add( new Price( 10 ) );
list.add( new Price( 11 ) );
list.add( new Price( 12 ) );
list.add( new Price( 11 ) );
list.add( new Price( 12 ) );

//....
Iterator<Price> iterator = list.iterator();
while ( iterator.hasNext() ) { 
  Price price = iterator.next(); 
  //analyze
}

Listening for List Item Events

Hazelcast List uses ItemListener to listen to events which occur when items are added and removed from the List. Use the list addItemListener method to create an ItemListener.

import java.util.Queue;
import java.util.Map; 
import java.util.Set; 
import com.hazelcast.core.Hazelcast;
import com.hazelcast.core.ItemListener;
import com.hazelcast.core.EntryListener;
import com.hazelcast.core.EntryEvent; 

public class Sample implements ItemListener{

  public static void main( String[] args ) { 
    Sample sample = new Sample();
    HazelcastInstance hazelcastInstance = Hazelcast.newHazelcastInstance();
    IList<Price> list = hazelcastInstance.getList( "default" );
    list.addItemListener( sample, true ); 

    Price price = new Price( 10, time1 )
    list.add( price );
    list.remove( price );
  } 

  public void itemAdded( Object item ) {
    System.out.println( "Item added = " + item );
  }

  public void itemRemoved( Object item ) {
    System.out.println( "Item removed = " + item );
  }     
}



RELATED INFORMATION

To learn more about the configuration of listeners please refer to the Listener Configurations section.



RELATED INFORMATION

Please refer to the List Configuration section for a full description of Hazelcast Distributed List configuration.