MessageBatch batch=new MessageBatch(10);
for(int j=0; j < 2; j++)
for(int i=1; i <= 5; i++)
batch.add(new Message(null, i));
System.out.println(batch.map(print_numbers));
assert batch.size() == 10;
batch.replace(filter, null, true);
assert batch.size() == 5;
System.out.println(batch.map(print_numbers));
}