Ryo Yamazaki ymnder

Writing Resilient Reactive Applications

This guide is a first draft (that will end up in the official docs) on writing resilient code for production with the Couchbase Java SDK. At the end, the reader will be able to write code that withstands bugs, latency issues or anything else that can make their application fail.

Note that lots of concepts can be applied for both synchronous and asynchronous access. When necessary, both patterns are discussed separately. Also, the focus is on database interaction, but if you are using RxJava as part of your stack you can apply most of the principles there as well (and should!).

RxJava 101 Recap: Cold and Hot Observables

When working with Observables, it is important to understand the difference between cold and hot. Cold Observables will start to emit events once a Observer subscribes, and will do it "fresh" for each Observer. Hot Observables instead are starting to emit data as soon as it becomes available, and will return the same (or parts of the same)

	package jp.example.android.util.html

	import android.content.Context
	import android.graphics.Bitmap
	import android.support.v4.content.ContextCompat
	import android.text.SpannableString
	import android.text.SpannableStringBuilder
	import android.text.Spanned.SPAN_INCLUSIVE_INCLUSIVE
	import android.text.style.TextAppearanceSpan
	import android.view.Gravity.CENTER

	// #関数定義
	// fun [関数名] ( [引数名1]:[型], [引数名2]:[型] ... ): [返り値型] { [式] }
	fun addOne(num: Int): Int {
	num+1
	}

	// fun [関数名] ( [引数名1]:[型], [引数名2]:[型] ... ): [返り値型] = { [式] }
	fun addOne(num: Int): Int = num+1

	// 返り値の型が自明な場合は省略可(可読性下がるため非推奨)

	private class HttpInterceptor implements Interceptor {

	@Override
	public Response intercept(Chain chain) throws IOException {
	Request request = chain.request();

	//Build new request
	Request.Builder builder = request.newBuilder();
	builder.header("Accept", "application/json"); //if necessary, say to consume JSON