[SOLVED]EntrySet is not supported by Example

Hi there

I have a project for add a operator to RM, Recently, I use the iterator for deal with 'example'. like:

 

public Reader(Example example) {
			this.example = example.entrySet().iterator();
		}

but once I execute my operator, a report of bug will be shown:

SEVERE: Process failed: operator cannot be executed (EntrySet is not supported by Example.). Check the log messages...
java.lang.UnsupportedOperationException: EntrySet is not supported by Example.

but, example is a type of Map<String, Object> ?

Could you help me?

Thanks a lot.

Jiang