“ .and”和“ where”代表什么？

Question

I can't understand the following code:

final Specifications<PaymentBatch> criteriaSpecification = 
        where(paymentBatchesInZone(getCurrentZone()))
        .and(new PaymentBatchSearchFilter(paymentBatchSearchQueryDTO));

What do .and and where stand for?

Answer 1

This is a pattern called fluent interface .

For details see here: Is it bad practice to make a setter return "this"?

Every call to a function returns the current object so subsequent method calls may be made without having a separate reference declared.

Thus both methods where() and and() are parts of a DAO pattern and provide the means to create an SQL WHERE statement.