java streams between java 8 and Java 7

Question

I have the following method in Java 8 and I'm working in project using java 7:

public <T> List<T> getValues(CommandLineItem commandLineItemMod, Class<T> targetClass) {
    Object value = values.get(commandLineItemMod);
    ArrayList<T> result = new ArrayList<>();
    if (value instanceof Collection) {
        Collection<?> sourceCollection = (Collection<?>) value;
        result.ensureCapacity(sourceCollection.size());
        sourceCollection.stream().map(o -> convertValue(o, targetClass)).forEach(result::add);
    } else if (value != null) {
        result.add(convertValue(value, targetClass));
    }

    return result;
}

my question is how I can transfer the following line from java 8 to java 7 :

 sourceCollection.stream().map(o -> convertValue(o, targetClass)).forEach(result::add);

thank you for your help

Dorian Gray · Accepted Answer · 2022-01-09 14:43:59Z

2

The line

sourceCollection.stream().
                .map(o -> convertValue(o, targetClass))
                .forEach(result::add);

can be rewritten as:

for (Object o: sourceCollection) {
    result.add(convertValue(o, targetClass));
}

which (IMO) is a clearer way to write the code in the first place.

Having said that, public (free) support for Java 7 ended in 2015, and premium (paid) support ended in Jul7 2019. (See https://www.oracle.com/java/technologies/java-se-support-roadmap.html). So the application you are working on is on borrowed time. I would have thought it would be more sensible to port the application to a newer Java version (or phase it out entirely) rather than expending valuable developer effort on backporting Java 8 code to it.

edited Jan 9, 2022 at 14:43

Dorian Gray

2,9911 gold badge12 silver badges26 bronze badges

answered Jan 9, 2022 at 10:17

Stephen C

723k95 gold badges849 silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

Comments

gkatiforis · Accepted Answer · 2022-01-10 08:51:27Z

1

Java 7 doesn't support Stream API. You have to use a for loop:

 for(Object source : sourceCollection){
     result.add(convertValue(source, targetClass));
 }

edited Jan 10, 2022 at 8:51

answered Jan 9, 2022 at 10:14

gkatiforis

1,6521 gold badge10 silver badges19 bronze badges

1 Comment

Mohamed MAOUCHI Over a year ago

thanks for the help

Collectives™ on Stack Overflow

java streams between java 8 and Java 7

2 Answers 2

Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related