Java Functional interfaces

By -

Functional interfaces

If an interface only has one abstract method (aside from methods of Object), it’s called functional interface. Functional interfaces are special because instances of functional interfaces can be created with lambda expressions or method references.

If an interface is designed to be functional, it should be marked with @FunctionalInterface annotation. Compiler will generate an error if the interface doesn’t meet the requirements of being a functional interface.


There are already several functional interfaces, e.g.
• java.lang.Runnable
• java.util.concurrent.Callable
• java.util.Comparator
• java.io.FileFilter

Java SE 8 adds a new package java.util.function which includes new functional interfaces.

Functional interfaces and single responsibility principle 
"Single responsibility principle" states that every class should only have one responsibility and only one reason to change. Functional interfaces only provide one abstract method to implement, which makes functional interfaces the nature choice to apply single responsibility principle. With the power of lambda expressions, implementing function interfaces is also very elegant. Using functional interfaces is a good combination of design principle and coding practice. When writing your own application, try to always use functional interfaces. This can also help to create better design. http://en.wikipedia.org/wiki/Single_responsibility_principle

Comments

Post a Comment

Popular posts from this blog

Today Walkin 14th-Sept

By -
Image
14th Sept 2017 ( GO Through all List) Read Walkin details properly , Try to call company before attending if possible !!! ==================================== 1. Myntra through fresherworld (Call Based , Venue shared to shortlisted candidates) _____________________________ 2. Magna : Hiring for Client Harman : C++
Read more

Hibernate Search - Elasticsearch with JSON manipulation

By -
Elasticsearch with JSON manipulation Elasticsearch ships with many features. It is possible that at some point, one feature you need will not be exposed by the Search DSL. To work around such limitations, Hibernate Search provides ways to: Transform the HTTP request sent to Elasticsearch for search queries. Read the raw JSON of the HTTP response received from Elasticsearch for search queries. Direct changes to the HTTP request may conflict with Hibernate Search features and be supported differently by different versions of Elasticsearch. Similarly, the content of the HTTP response may change depending on the version of Elasticsearch, depending on which Hibernate Search features are used, and even depending on how Hibernate Search features are implemented. Thus, features relying on direct access to HTTP requests or responses cannot be guaranteed to continue to work when upgrading Hibernate Search, even for micro upgrades (x.y.z to x.y.(z+1)). Use this at your own risk.
Read more

Spring Elasticsearch Operations

By -
Elasticsearch Operations Spring Data Elasticsearch uses two interfaces to define the operations that can be called against an Elasticsearch index. These are ElasticsearchOperations and ReactiveElasticsearchOperations. Whereas the first is used with the classic synchronous implementations, the second one uses reactive infrastructure. The default implementations of the interfaces offer: Read/Write mapping support for domain types. A rich query and criteria api. Resource management and Exception translation. ElasticsearchTemplate The ElasticsearchTemplate is an implementation of the ElasticsearchOperations interface using the Transport Client. @Configuration public class TransportClientConfig extends ElasticsearchConfigurationSupport {   @Bean   public Client elasticsearchClient() throws UnknownHostException {                      Settings settings = Settings.builder().put("cluster.name", "elasticsearch").build();     TransportClient client = new P
Read more