I have a forEach loop and for performance issues I'm told to use Java stream instead of this. I have multiple cases and my code is like below. I couldn't found any stream example with multiple cases. Could anyone help me to convert this? Thanks a lot in advance.
name = "Serena";
for(Integer age : ages){
if(age>10 && age<20)
methodA(name);
else if(age>20 && age<30)
methodB(name);
else
methodC(name);
For the updated question, Stream API may be used to map the age into Consumer<String>
using references to methods methodA, methodB, methodC
and then invoke Consumer::accept
but this does not seem to be very useful and can be considered just as an exercise:
public static void main(String .... args) {
List<Integer> ages = Arrays.asList(1, 10, 15, 20, 22, 30, 33);
ages.stream()
.map(MyClass::byAge)
.forEach(action -> action.accept("Serena"));
}
// mapper to specific method
static Consumer<String> byAge(int age) {
return 10 < age && age < 20
? MyClass::methodA
: 20 < age && age < 30
? MyClass::methodB
: MyClass::methodC;
}
// consumer methods
public static void methodA(String name) {
System.out.println("A: " + name);
}
public static void methodB(String name) {
System.out.println("B: " + name);
}
public static void methodC(String name) {
System.out.println("C: " + name);
}
List<Integer> ints = Arrays.asList(11, 22, 30, 40);
ints.forEach(i -> {
if (i> 10 && i < 20) {
System.out.println("Value between 10 & 20");
} else if(i >= 20 && i < 30) {
System.out.println("Value between 20 & 30");
} else if(i>=30 && i <40) {
System.out.println("Value between 30 & 40");
}
});
You could just use forEach with your code. Not sure if this is what you want or why.
ages.forEach(age -> {
if(age > 10 && age < 20) {
methodA(age);
}
else if(age > 20 && age < 30) {
methodB(age);
}
else {
methodC(age);
}
});
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