CODEWITHSUNDEEP
javajava-8java-stream
Krish
Krish

Reputation: 4232

How to compare two arrayList's objects elements in java 8

I am trying to compare one arrayList object elements contains another arraylist with below code but this is not working as i expected can some one help me please

arrayList1=[{productSku:"123"},{productSku:"1234"}]
arrayList2=[{productSku:"123"},{productSku:"1000"}]

My scenario is if arraylist1 elements not matching with any of the element in arraylist2 then we should throw exception

arrayList2.stream().filter(type -> "EQUIPMENT".equals(type.getItemType()))
                        .forEach(action -> {                             
            arrayList1.forEach(action1 -> {
                                if (!action1.getProductSku().equalsIgnoreCase(action.getProductSKU())) {
                                    // Throw exception
                                }
                            });
                        });

Upvotes: 0

Views: 1235

Answers (2)

Yassin Hajaj
Yassin Hajaj

Reputation: 21975

While Deadpool's answer is great, I'd be more inclined to avoid using Optional here, as there is no use for the actual value to be used.

Also, creating a Stream for each element traversing the Stream is not a good idea in terms of performance.

Set<String> products = arrayList1.stream()
                                 .map(Action::getProductSku)
                                 .map(String::toUpperCase)
                                 .collect(toSet());

boolean shouldThrowAnException = arrayList2.stream()
                                           .filter(type -> "EQUIPMENT".equals(type.getItemType()))
                                           .map(Action::getProductSku)
                                           .map(String::toUpperCase)
                                           .noneMatch(products::contains);

if (shouldThrowAnException) {
    // throw exception
}

Upvotes: 2

Ryuzaki L
Ryuzaki L

Reputation: 40048

You can stream the arrayList2 and try finding at least one matching element in arrayList1 using findFirst or else throw exception

arrayList2.stream()
     .filter(type -> "EQUIPMENT".equals(type.getItemType()))
     .filter(list2-> arrayList1.stream()
           .anyMatch(list1->list1.getProductSku().equals(list2.getProductSku())))
     .findFirst()
     .orElseThrow(//some exception)

Upvotes: 1

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