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www.morling.dev | ||
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konradreiche.com
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| | | | | Since most of the Java code I wrote in the past was on Android I was not able to enjoy too many Java 8 features yet. Though recently I wrote a microservice in Java using Spring Boot where I could make full use of lambdas and functional interfaces. The following method, for instance, returns the sum of all transactions for a specified instance by traversing their children. @RequestMapping(value = "/transaction/sum/{id}", method = RequestMethod.GET) BigDecimal Sum sum(@PathVariable long id) { List transactions = new ArrayList<>(); Transaction current = repository.find(id); while (current != null) { transactions.add(current); current = current.getChild(); } return transactions.stream().map(t -> t.getAmount()) .reduce(BigDecimal.ZERO, BigDecimal::add); } As some... | |
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studiofreya.org
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richardstartin.github.io
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| | | | | The streams API has been around for a while now, and I'm a big fan of it. It allows for a clean declarative programming style, which permits various optimisations to occur, and keeps the pastafarians at bay. I also think the Stream is the perfect abstraction for data interchange across API boundaries. This is partly because a Stream is lazy, meaning you don't need to pay for consumption until you actually need to, and partly because a Stream can only be used once and there can be no ambiguity about ownership. If you supply a Stream to an API, you must expect that it has been used and so must discard it. This almost entirely eradicates defensive copies and can mean that no intermediate data structures need ever exist. Despite my enthusiasm for this abstractio... | |
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sookocheff.com
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| | | One of the core features of modern Java is lambda expressions. Introduced in Java 8, lambdas provide concise syntax allowing the deferred execution of a block of code. Put a different way, lambdas allow us to pass behaviour as a method parameter. When the method executes, the lambda expression is run. This capability is often referred to as behaviour parameterization. Behaviour parameterization can be achieved in a number of ways, of which lambda expressions are usually the most convenient, and they are definitely the most concise. But what is behaviour parameterization, and why would we want to use it? To motivate this discussion, let's work through a real-world example of filtering a list of items according to some criteria. More concretely, let's investig... | ||
