# Replace For-Loop with Stream::takeWhile
# Description
The Stream API in Java 9 is extended with the takeWhile (opens new window) method to get the prefix of a stream.
This rule replaces the enhanced for-loops iterating over the prefix of a collection with Stream::takeWhile.
Requirements
Java 9
# Benefits
Applying this rule results in better readability and more compact code.
# Tags
# Code Changes
# Iterating over a List
Pre
List<User> users = findAllSorted();
for(User user : users) {
if(!isImportantCustomer(user)) {
break;
}
attachDiscount(user);
}
Post
List<User> users = findAllSorted();
users.stream()
.takeWhile(user -> isImportantCustomer(user))
.forEach(user -> applyDiscount(user));
# Iterating over a Map
Pre
Map<Integer, User> users = findAllSorted();
for(Map.Entry<Integer, User> entry : users.entrySet()) {
if(!isEarlyCustomerId(entry.getKey())) {
break;
}
User user = entry.getValue();
attachDiscount(user);
}
Post
Map<Integer, User> users = findAllSorted();
users.entrySet()
.stream()
.takeWhile(entry -> isEarlyCustomerId(entry.getKey()))
.forEach(entry -> {
User user = entry.getValue();
attachDiscount(user);
});
Use a Java Refactoring Tool
No license required
You can review this refactoring on your code without a license by installing jSparrow to your Eclipse IDE. Install the plug-in from Eclipse IDE: Eclipse Marketplace.
System-wide Refactoring
Do you want to automate this refactoring (and many more) to your system-wide code? The automatic application of this system-wide refactoring can be unlocked by acquiring your jSparrow license.
# Properties
| Property | Value |
|---|---|
| Rule ID | EnhancedForLoopToStreamTakeWhile |
| First seen in jSparrow version | 3.7.0 |
| Minimum Java version | 9 |
| Remediation cost | 2 min |