Serialize every new entry in a HashMap

[Damodar Mukhopadhyay]

Hi All,
Any idea how I can serialize every single entry in a HashMap to a single file?
For example, say I when I add a new entry to a HashMap the entry should serialize in a file and not the entire HashMap.


Regards,
Damodar

[Rob Spoor]

You should create a custom Map implementation (extends HashMap if you want) that overrides put and putAll, but also remove, clear, removeAll and retainAll not only of the Map but also its entrySet, keySet and values.

[Damodar Mukhopadhyay]

Thanks Rob, but how serialize will work here?

[shalindra Singh Suryvanshee]

Thanks Rob, but how serialize will work here?

To make your serialize work, you may over-ride readObject() and writeobject() method which should only read and write only updated keys and values from HashMap.

[Damodar Mukhopadhyay]

Can I write the updated object into an existing serialized file?
Say the .ser file already has 10 HashMap Key value pair now can I add one more into it?
Could you please give an example?

Regards,
Damodar

[Paul Clapham]

Did you try it?

I don't see why you need an example, you already know how to serialize an object to a file. Don't you?

[Damodar Mukhopadhyay]

Yes, but I am afraid, if the system crash and not able to close the Stream? also do I require flash() after avary new entry in the .ser file?