# Replace For-Loop with Stream::sum
# Description
Transforms enhanced for-loops which are only used for summing up the elements of a collection into a stream and uses the sum operation to compute the result.
# Benefits
Applying this rule yields no major performance benefits. One could argue that readability is somewhat improved, at least if one is familiar with lambdas.
# Tags
# Code Changes
# List of integers
Pre
List<Integer> numbers = generateIntList(input);
int sum = 0;
for(int n : numbers) {
sum += n;
}
Post
List<Integer> numbers = generateIntList(input);
int sum = numbers.stream().mapToInt(Integer::intValue).sum();
# List of doubles
Pre
List<Double> numbers = generateDoubleList(input);
double sum = 0;
for(double n : numbers) {
sum += n;
}
Post
List<Double> numbers = generateDoubleList(input);
double sum = numbers.stream().mapToDouble(Double::doubleValue).sum();
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 | EnhancedForLoopToStreamSum |
| First seen in jSparrow version | 2.2.0 |
| Minimum Java version | 8 |
| Remediation cost | 10 min |