Salesforce Design Patterns

This repository includes an examples of patterns realisation in Apex.

Factory Method

The factory method is just a method, it can be overridden in a subclass, whereas the abstract factory is an object that has multiple factory methods on it.

Examples:

• Factory Method Test
• Apex Test Data Factory

Builder

The builder pattern is used to instantiate an object of a complex class using the step-by-step approach and return a constructed object at once. Allows creating different products based on the same process.

Examples:

• Builder Test
• Apex-query-builder

Interpreter

Interpreter pattern is used to define a grammatical representation for a language and provides an interpreter to deal with this syntax.

• This pattern is used in SOQL parsing, symbol processing engine etc.
• This pattern performs upon a hierarchy of expressions. Each expression here is a terminal or non-terminal.
• The tree contains the expressions to be evaluated and is usually generated by a parser. The parser itself is not a part of the interpreter pattern.

Examples:

• Interpreter Test
• Script

Singleton

The singleton design pattern restricts the instantiation of a class to only one object.

• This pattern is used in SOQL parsing, symbol processing engine etc.
• This pattern performs upon a hierarchy of expressions. Each expression here is a terminal or non-terminal.
• The tree contains the expressions to be evaluated and is usually generated by a parser. The parser itself is not a part of the interpreter pattern.

Examples:

• Interpreter Test
• Script