This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
You can use EL tags to set the enabled attribute for the inputText controls from false to true, but why do that through a double click event? You'd probably be better off using some other control, like a checkBox, in a component library that uses AJAX to enable those fields. In any case you'll probably have to override part of the JSF life cycle to accomplish what you're trying to do.