Filter collections with lambdaj

Question

Filter collections with lambdaj

I have two classes:

public class Order{
    private Integer id;
    private List<Position> positions;
    ...
}

public class Position{
    private Integer id;
    private String content;
    ...
}

Now I have a list with orders and you want to receive all orders with line items with specific content. At the moment, I am doing it like this:

List<Order> orders = ... ;

List<Order> outputOrders = ... ;
for(Order order : orders){
    if(select(order.getPositions(), having(on(Position.class).getContent(),equalTo("Something"))).size() != 0){
        outputOrders.add(order);
    }
}

Is there a better way to do this with lambdaj?

Thanks in advance.

+5

java collections filtering lambdaj

Qri Mar 18 '13 at 8:43

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1 answer

longhua · Accepted Answer · 2013-03-18T10:34:26+0000

How about this: use org.hamcrest.Matchers.hasItem?

List<Order> outputOrders =
        filter(having(on(Order.class).getPositions(),
                      hasItem(having(on(Position.class).getContent(),
                                     equalTo("Something")))),
               orders);

Filter collections with lambdaj

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