I am facing some strange problem in lucene search.
My lucene document has three field
1. name
2. description
3. themeid

i am creating my indexes with these three fields.
I have these scenario in search.
I have text field where user can enter keyword to be searched.
My problem is when user does not enter any keyword and press enter no search result is shown.
But i want to show all the document in this case. I have pagination implemented so its not a problem to show thousands of result at one time.
Why lucene doesn't allow this.

Please help me in this matter.