David N Hamilton jiffle

Command Cheatsheet

Convert Maven build to gradle

gradle init
Initialise new project folder structure (Java example)

gradle init --type java-library

Java Lambda Syntax

As an expression

(Person p) -> p.getGender() == Person.Sex.MALE
    && p.getAge() >= 18
    && p.getAge() <= 25

As a local variable

Design Patterns implemented in Java 8

These patterns are implemented using Java 8 Lambdas (together with Project Lombok annotations).

Factory Pattern

Factory I : No Parameter Constructor

Enum class:

Spock Useful Patterns Cheatsheet

Adding sequences of behaviour to Mocks and Stubs

The >>> operator allows a sequence of values to be returned:

myMock.someCall() >>> ['first value', 'second value', 'third value', 'etc']

This returns each string in turn. Behaviour (such as throwing exceptions) in closures cannot be used by this operator.

The >> operator allows value or behaviour (closures) to be returned

Military Style For Effective Email Communications

The military structure their communications for maximum clarity and conciseness. These are the key points to write emails in an fffective manner:

1. Prefix Email subject with keyword

Format: STATUS - Message Title

Status keywords:

Evolving Rest Services and Backward Compatibility

My aim is to define a set of rules that can be used to decide whether an incremental data change is backwardly compatible or not, list things to beware of for a particular change, and mitigations that can be put in place.

Clearly it is assumed that the services will be using API versioning, and that a major API version number change would allow any required change to that API. The scope of this document is to explore what changes can be made within a single API version.

Main Release Management models

There are four main release management models, each of which has its own requirements and challenges in versioning the APIs.

Kotlin provides significantly improved support for nullable (and non-nullable) types.

These are all the language and Kotlin library features that help support working with nullable types:

Fundamentals

Non-nullable type declaration:

var a: String = "abc"

Kotlin Programming Language - Part 1

Kotlin language website is at https://kotlinlang.org.

All the codes here can be copied and run on Kotlin online editor.

Basics

You do not need ; to break statements.
Comments are similar to Java or C#, /* This is comment */ for multi line comments and // for single line comment.

Core Language Methods

Block method	Returns	Thread	Notes
launch	Job	From Pool parameter
async	Deferred	From Pool parameter	Use `await` to get result
withTimeout	value from Coroutine	From Pool parameter
thread	Null	New thread	Not a coroutine, but same as launch

	// imports a couple of java tasks
	apply plugin: "java"

	// List available tasks in the shell
	> gradle tasks

	// A Closure that configures the sourceSets Task
	// Sets the main folder as Source folder (where the compiler is looking up the .java files)
	sourceSets {
	main.java.srcDir "src/main"