Observer Pattern maintains a one-to-many dependency between a Subject and its dependents so that when the state of the Subject changes, dependents get notified.
Today, I will discuss simple and very useful behavioral design pattern called — Observer Design Pattern. This design pattern is useful when we want get notified about changes in the object state.
Observableis quite limited, the order of notifications delivered by
Observableis unspecified, and state changes are not in one-for-one correspondence with notifications. For a richer event model, consider using the java.beans
package. For reliable and ordered messaging among threads, consider using one of the concurrent data structures in thejava.util.concurrent
package. For reactive streams style programming, see theFlow API. (read more on Deprecate Observer and Observable).
Now an example to understand the implementation of Observer Design Pattern.
Suppose there are some public figures like politicians or celebrities for which there are some followers. Whenever these public figures do any tweet, there registered followers get the notification on that.
In this blog, we will discuss Proxy Design Pattern, its example, and how it is different from the other design patterns. But, it’s important to have an understanding of the design patterns first. You can refer here.
"Java Design Patterns for Beginners - Design Patterns in Java - Design Patterns Tutorial" will provide you with detailed knowledge about Java Design Patterns and along with it. Why do we need Design Patterns? Structure of Design Patterns. Types of Design Patterns. Creational Design Patterns. Factory Design Pattern. Overview of Design Patterns
What is OpenJDK? OpenJDk or Open Java Development Kit is a free, open-source framework of the Java Platform, Standard Edition (or Java SE).
This post looks at how to use the composite design pattern in Java, specifically the objects used in the pattern: component, composite, leaf, and client.
Today, I would like to discuss another behavioral design pattern called the Memento Design Pattern which is used to restore the state of an object to a previous state.