This method is used to check whether an Optional object is empty or not? If not, then do the operations with this object, otherwise do not do anything. The parameter of this method is an object of the Consumer interface. You can see more about… Read More
In this tutorial, I will show you all how to remove a Container in Docker. The first is the way to remove a Container. To remove a Container in the Docker, the first thing you need to do is to determine the Container ID or… Read More
The Optional object in Java has three methods with name start with or(). In this tutorial, we will together learn about them and what is the difference between them. First, I might mention the orElse() method. This method is used to return a default value in… Read More
Supplier is a Functional Interface, so it only contains an abstract method as follows:
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package java.util.function; /** * Represents a supplier of results. * * <p>There is no requirement that a new or distinct result be returned each * time the supplier is invoked. * * <p>This is a <a href="package-summary.html">functional interface</a> * whose functional method is {@link #get()}. * * @param <T> the type of results supplied by this supplier * * @since 1.8 */ @FunctionalInterface public interface Supplier<T> { /** * Gets a result. * * @return a result */ T get(); } |
This interface simply returns the value in the context that is being used by the get() method. For example, we have the following list:
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List<String> s = Arrays.asList("Khanh", "Quan"); |
Now that I want to… Read More
Java 8 introduces a new package containing Functional Interfaces called java.util.function. In this package, we have many interfaces like Consumer, Supplier, Predicate, … In this tutorial, we will learn about Consumer Functional Interface. The content of this interface is as follows:
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package java.util.function; import java.util.Objects; /** * Represents an operation that accepts a single input argument and returns no * result. Unlike most other functional interfaces, {@code Consumer} is expected * to operate via side-effects. * * <p>This is a <a href="package-summary.html">functional interface</a> * whose functional method is {@link #accept(Object)}. * * @param <T> the type of the input to the operation * * @since 1.8 */ @FunctionalInterface public interface Consumer<T> { /** * Performs this operation on the given argument. * * @param t the input argument */ void accept(T t); /** * Returns a composed {@code Consumer} that performs, in sequence, this * operation followed by the {@code after} operation. If performing either * operation throws an exception, it is relayed to the caller of the * composed operation. If performing this operation throws an exception, * the {@code after} operation will not be performed. * * @param after the operation to perform after this operation * @return a composed {@code Consumer} that performs in sequence this * operation followed by the {@code after} operation * @throws NullPointerException if {@code after} is null */ default Consumer<T> andThen(Consumer<? super T> after) { Objects.requireNonNull(after); return (T t) -> { accept(t); after.accept(t); }; } } |
Because the Consumer… Read More
Docker is a tool for creating stable environments with applications, enabling us to easily run these built-in environments on different systems. How it is in details, I will have some incoming posts about it. In this tutorial, I only guide you to install Docker on… Read More
This method is supported since Java 9. This method is used to create a new Stream object from an Optional object in Java. If the Optional object contains a value, this method will return the Stream object containing that value, otherwise, it returns an empty… Read More
In previous tutorials about introducing aspect oriented programming and compiling-time weaving with AspectJ, I introduced you all to the @Before annotation and @After annotation to insert the code before and after when our application call to a method of an object. They are the Advice. In… Read More
In the previous tutorial Introduce about Aspect Oriented Programming, I introduced three ways to insert code using AspectJ: compile-time weaving, post-compile weaving, and load-time weaving. Compile-Time Weaving is the simplest and easiest way to insert the code that will occur when we compile the source… Read More
In my previous tutorial, I showed you all an overview of Spring Data JPA and made an example of using the findById() method available in the JpaRepository interface to query the database for the data in the primary key column and method findByName() to retrieve… Read More
