{"id":279,"date":"2016-12-06T10:28:12","date_gmt":"2016-12-06T10:28:12","guid":{"rendered":"https:\/\/sidroniolima.com.br\/blog\/?p=279"},"modified":"2016-12-14T17:09:00","modified_gmt":"2016-12-14T17:09:00","slug":"lambdas-oracle-mooc","status":"publish","type":"post","link":"https:\/\/sidroniolima.com.br\/blog\/2016\/12\/06\/lambdas-oracle-mooc\/","title":{"rendered":"Lambdas Oracle MOOC"},"content":{"rendered":"\n
Tweet<\/a><\/div>\n

\"Java<\/p>\n

Section 1<\/h1>\n

– Need changes to Java to simplify parallel coding.
\n– Lambda expressions simplify how to pass behavior as a parameter.<\/p>\n

-Show the differences through Java basic code, inner classes and lambdas.<\/p>\n

Non-functional (imperative) programming style versus functional.<\/p>\n

Problem: external iteration.
\nAfter: more functional with inner classes;
\nAnd then: lambda approach, more concise, less code (error-prone), client logic is stateless, thread-safe.<\/p>\n

The lambda expression provides the implementation of the abstract method. The type is the abstract method.<\/p>\n

@FunctionalInterface -> Functional Interface = an interface with one abstract method; default doesn’t count. The equals<\/em> also doesn’t count in therms of abstract method.<\/p>\n

Variable assignment: Callable c = () -> process();<\/p>\n

Method parameter: mew Thread(() -> process()).start();<\/p>\n

Lambda expressions can be used anywhere the type is a functional interface.<\/p>\n

– A functional interface has only one abstract method.<\/p>\n

The lambda expression provides the implementation of the single abstract method of the functional interface.<\/p>\n

java.util.function Package<\/h3>\n

Consumer<T><\/h4>\n

Operation that takes a single value and return no result: String s -> System.out.println(s) .<\/p>\n

Example: String s -> System.out.println(s);<\/em><\/p>\n

BiConsumer<T,U><\/h4>\n

Takes two values and returns no result.<\/p>\n

Example: (k,v) -> System.out.println(“key: ” + k + “, value: ” + v);<\/em><\/p>\n

Supplier<\/h4>\n

The opposite of a Consumer. Doesn’t take any parameter and returns a value.<\/p>\n

Example: ( ) -> createLogMessage();<\/em><\/p>\n

Function<T,R><\/h4>\n

Takes one argument, do something and returns a result.<\/p>\n

Example: Student s -> s.getName();<\/em><\/p>\n

BiFunction<T,U,R><\/h4>\n

Takes two arguments and returns a result.<\/p>\n

Example: (String name, Student s) -> new Teacher(name, student);<\/em><\/p>\n

UnaryOperator<T><\/h4>\n

Kind function: single argument and result of the same type.<\/p>\n