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javafilterjava-8predicate

Filter predicate for equalsIgnoreCase

I am trying to write a filter predicate for Objects.nonNull and equalsIgnoreCase, but I am not able to create a predicate for the equalsIgnoreCase part. Can I have some suggestions?

My code is :

basicDetailEntity.forEach(prj -> {
    CharlieAddress billToAddress = addressList.stream()
        .filter(add -> Objects.nonNull(add.getSiteDuns())
                       && add.getSiteDuns().equalsIgnoreCase(prj.getBillToDuns())
                       && Objects.nonNull(add.getOrgName())
                       && add.getOrgName().equalsIgnoreCase(prj.getOperatingUnit()))
        .findFirst().orElse(null);

I have created the two predicates for the nonNull part, but I'm finding it difficult to create them for the equalsIgnoreCase one, any suggestion will help.

public static final Predicate<CharlieAddress> CHARLIE_ADDRESS_DUNS_PRESENT =
        add -> Objects.nonNull(add.getSiteDuns());

public static final Predicate<CharlieAddress> CHARLIE_ADDRESS_ORG_PRESENT =
        add -> Objects.nonNull(add.getOrgName());
Solution

  • The problem is that your condition relies upon two arguments. You need the address and you need the prj (project? -- the rest of this answer assumes so).

    add.getSiteDuns().equalsIgnoreCase(prj.getBillToDuns())
 ^                                  ^

    A predicate takes a single argument and returns a boolean, so unless you have a lambda that acts as a closure which captures some variable from the enclosing scope (which if you want the predicate to be a static field, you probably do not) then what you're asking for is not possible

    final Project prj = /*something*/; // must be final or "effectively final"
Predicate<CharlieAddress> foo =
    add -> add.getSiteDuns().equalsIgnoreCase(prj.getBillToDuns());
                                            // ^ captured

    There is another interface, BiPredicate which takes 2 arguments. Maybe that's what you're looking for.

    BiPredicate<CharlieAddress, Project> foo =
    (add, prj) -> add.getSiteDuns().equalsIgnoreCase(prj.getBillToDuns());

    You didn't ask but your existing predicates can be simplified with != null

    public static final Predicate<CharlieAddress> CHARLIE_ADDRESS_DUNS_PRESENT =
    add -> add.getSiteDuns() != null;

public static final Predicate<CharlieAddress> CHARLIE_ADDRESS_ORG_PRESENT =
    add -> add.getOrgName() != null;