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This article focuses on "the results and applicable scenarios of the java combination model". Interested friends may wish to take a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn the results and applicable scenarios of the java combination model.

Definition of Composite pattern: sometimes called part-whole pattern, it is a pattern that combines objects into a tree-like hierarchical structure to represent the "part-whole" relationship. The combination mode allows client code to consistently handle individual objects and composite objects, regardless of whether it is dealing with a single object or a combined object, which simplifies the client code.

Pattern structure

Top-level abstraction: an abstract interface for branches or leaves

Branch: a leaf node object in a composition that has no child nodes and is used to implement a common interface declared in an abstract component role.

Leaf: a branch node object in a combination that has child nodes. It implements the interfaces declared in abstract component roles, and its main role is to store and manage child components.

Source code guide

The combination mode is divided into transparent mode and security mode; transparent mode declares all the methods of managing sub-objects in the top-level abstraction, and there is no difference between leaf nodes and branch nodes for the client. Security mode is an abstract method that only declares leaves and branches in the top-level abstraction, and implements the management methods of leaves and branches into the corresponding class, so the client needs to distinguish whether the node is a branch or a leaf in order to call the corresponding method.

For composition patterns, collection classes such as List Set belong to less strict composition patterns. Since I can't find a good source code, I will explain the combination of transparent mode and security mode here.

Transparent mode:

Public abstract class Component {private String name; public Component (string name) {this.name = name;} public abstract boolean Add (Component component); public abstract boolean Remove (Component component); public String getName () {return name;}} public class Branch extend Component {private List tree=new ArrayList (); public Branch (String name) {super (name) } public boolean add (Componet component) {tree.add (component); return true;} public boolean Remove (Component component) {tree.remove (component); return true;}} public class Leaf extend Component {public Leaf (String name) {super (name);} public boolean add (Componet component) {return false } public boolean Remove (Component component) {return false;}}

Security mode:

Public abstract class Component {private String name; public Component (string name) {this.name = name;} public String getName () {return name;}} public class Branch extend Component {private List tree=new ArrayList (); public Branch (String name) {super (name);} public boolean add (Componet component) {tree.add (component); return true } public boolean Remove (Component component) {tree.remove (component); return true;} public List getTree () {return tree;}} public class Leaf extend Component {public Leaf (String name) {super (name);}}

The combination pattern is suitable for situations where the structural hierarchy of the whole and part of a system (component) needs to be expressed; the combination pattern can hide the difference between a composite object and a single object from the client, so that the client can use a unified interface to use all objects in the composite structure, and it is also suitable for this kind of situation.

At this point, I believe you have a deeper understanding of the results and applicable scenarios of the java combination model, so you might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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