# Use Optional::filter
# Description
Extracts an Optional::filter (opens new window) from the consumer used in Optional::ifPresent (opens new window).
Hence, simplifying the lambda expressions used with Optional operations.
This transformation is feasible only if the entire consumer's body is wrapped into an if-statement.
# Benefits
Arguably, the lambda expression is easier to read and can be combined with other Optional operations.
# Tags
# Code Changes
Pre
Optional<User> oUser = findById(userId);
oUser.ifPresent(user -> {
if (isSpecial(user)) {
sendMail(user.getMail());
}
});
Post
Optional<User> oUser = findById(userId);
oUser.filter(user -> isSpecial(user)).ifPresent(user -> {
sendMail(user.getMail());
});
# Limitations
Multiple Statements in Lambda Body - no transformation is feasible.
Pre
Optional<User> oUser = findById(userId);
oUser.ifPresent(user -> {
if (isSpecial(user)) {
sendPresent(user);
}
sendMail(user.getMail());
});
Use a Java Refactoring Tool
Automate this Refactoring system-wide
You can apply this refactoring for free with the jSparrow Eclipse IDE plug-in.
Install the plug-in for Eclipse IDE: Eclipse Marketplace.
# Properties
| Property | Value |
|---|---|
| Rule ID | OptionalFilter |
| First seen in jSparrow version | 3.14.0 |
| Minimum Java version | 8 |
| Remediation cost | 2 min |