CODEWITHSUNDEEP
javaandroidrx-javarx-android
shaikhmanzoor
shaikhmanzoor

Reputation: 89

Filter in RxJava

 class Transaction
 {
        int transactionId,transactionType,transactionStatus;
        double transactionAmount;
        Date transactionDate;    
}

I want to filter the list of transactions based on the combination Transaction property using RxJava. Combination changes runtime so someone can help me how to use filter() operator for the same

Upvotes: 0

Views: 703

Answers (1)

Rodrigo Henriques
Rodrigo Henriques

Reputation: 1812

Some time ago I had to do the same thing that you want to. I create a simple solution to handle multi filtering which looks like this:

public class ExampleUnitTest {
    @Test
    public void testSample() throws Exception {
        TransactionDatabase transactionDatabase = new TransactionDatabase();

        transactionDatabase.insert(new Transaction(1, 50.00, new Date()));
        transactionDatabase.insert(new Transaction(2, 20.00, new Date()));
        transactionDatabase.insert(new Transaction(3, 110.00, new Date()));
        transactionDatabase.insert(new Transaction(4, 250.00, new Date()));
        transactionDatabase.insert(new Transaction(5, 5.00, new Date()));
        transactionDatabase.insert(new Transaction(5, 73.00, new Date()));

        List<Func1<Transaction, Boolean>> filters = new ArrayList<>();

        filters.add(transaction -> transaction.transactionAmount > 20);
        filters.add(transaction -> transaction.transactionAmount < 100);

        transactionDatabase.getTransactions(filters)
                .subscribe(System.out::println);
    }

    private class Transaction {
        int transactionId;
        double transactionAmount;
        Date transactionDate;

        public Transaction(int transactionId, double transactionAmount, Date transactionDate) {
            this.transactionId = transactionId;
            this.transactionAmount = transactionAmount;
            this.transactionDate = transactionDate;
        }

        @Override
        public String toString() {
            return "Transaction{" +
                    "transactionId=" + transactionId +
                    ", transactionAmount=" + transactionAmount +
                    ", transactionDate=" + transactionDate +
                    '}';
        }
    }

    class TransactionDatabase {
        List<Transaction> transactions = new ArrayList<>();

        public void insert(Transaction transaction) {
            transactions.add(transaction);
        }

        public Observable<Transaction> getTransactions(List<Func1<Transaction, Boolean>> filters) {
            Observable<Transaction> observable = Observable.from(transactions);

            for (Func1<Transaction, Boolean> filter : filters) {
                observable = observable.filter(filter);
            }

            return observable;
        }
    }
}

It will print this:

Transaction{transactionId=1, transactionAmount=50.0, transactionDate=Tue Jun 14 16:21:24 BRT 2016}
Transaction{transactionId=5, transactionAmount=73.0, transactionDate=Tue Jun 14 16:21:24 BRT 2016}

I think that it is a pretty solution for your problem.

Hope that it helps.

Best regards.

Upvotes: 2

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