Best way to assign timestamp in coherence?

Question

What is the best way to assign a timestamp to an object when it is added to a cache? Should I just do this or is there something more efficient?
public class NewOrderTrigger implements MapTrigger {
    public NewOrderTrigger() {
    public void process(MapTrigger.Entry entry) {
        Order o = (Order)entry.getValue();
        o.setSubmittedTime(System.currentTimeMillis());
        entry.setValue(o);
    // ---- hashCode() and equals() must be implemented
    public boolean equals(Object o) {
        return o != null && o.getClass() == this.getClass();
    public int hashCode() {
        return getClass().getName().hashCode();
}Thanks,
Andrew

Answer 1

Hi Andrew,
There are couple issues I would like to bring to your attention.
1. The System.currentTimeMillis() API does not guarantee the time going forward. It's theoretically possible (e.g. with Time Synchronization Service) that with two consequent calls the second one returns value less than the first one. You could compensate for this effect by either using System#nanoTime() or com.tangosol.util.Base#getSafeTimeMillis()
2. The MapTrigger's process always has to deserialize and re-serialize the value. If your object model is POF aware, you could use the PofUpdater instead, optimizing out both steps:
public void process(MapTrigger.Entry entry) {
    PofUpdater updater = new PofUpdater(PROP_SUBMITTED_TIME);
    updater.update(entry, new Long(Base.getSafeTimeMillis()));
    }3. Updates that come from a single client node but belong to different partitions and land on different servers could have significantly different timestamps. Whether or not this is a concern depends on your usage of the SubmittedTime property.
Regards,
Gene