From May 18-20 myself and Richard attended the Google IO 2016 conference. We both visited different tracks and have some different experiences we'd like to share. Here are mine. Read on about topics in the likes of VR, Progressive Web Apps, and Artificial Intelligence. For a quick impression have a look at the photo album.
Last week I presented my talk 'MISSION TO MARS: EXPLORING NEW WORLDS WITH AWS IOT' at IoT Tech Day 2016 and it was great fun! In the presentation I showed how to build a small robot and control it over MQTT messaging via Amazons IoT platform. The room was packed and the demo went well too. I promised to share some info about it on my blog so here we are. I've composed a shopping list and a collection of useful links: Mission to Mars - Shopping list Mission to Mars - Useful links The original presentation is available here: Mission_to_Mars-Jeroen_Resoort-IoT_Tech_Day.pdf So what's next? I should publish my Pi robot and Mission Control Center web client code on github. Maybe I'll extend the python code for controlling the mBot over a serial connection and make a proper library for it.
Will keep you updated...
In AngularJS 1.5 we can use attribute binding to allow easy use of input-only, output-only and two-way attributes for a directive or component. Instead of manually parsing, watching and modifying attribute values through code, we can simply specify an attribute binding by adding a property to the object hash of:
scope / bindToController property of a Directive Definition Object (DDO)bindings of a AngularJS 1.5 component.IntelliJ IDEA 2016.1 introduced better support for Gradle source sets. Each source set in our project becomes a module in the IntelliJ IDEA project. And each module has it's own dependencies, also between source sets. For example if we simply apply the java plugin in our project we already get two source sets: main and test. For compiling the test sources there is a dependency to the main source set. IntelliJ now knows how to handle this.
Let's create a sample Gradle build file with an extra custom source set and see what we get in IntelliJ IDEA. In the following example build file we add the source set api. This source set contains interfaces without implementations. The implementations for the interfaces are in the default main source set. Finally we have some tests in the test source set that depend on the classes generated by the api and main source sets.
To create IntelliJ IDEA project files with Gradle we first need to apply the idea plugin. We can then further customise the created files. In this blog post we will add a Spring facet to the generated module file. By adding the Spring facet IntelliJ IDEA can automatically search for Spring configuration files. We can then use the Spring view to see which beans are configured in our project.
In the following example build file we use the withXml hook. This method is invoked just before the XML file is generated. We get an argument of type XmlProvider. From the XmlProvider we can access the XML as org.w3c.dom.Element, StringBuilder or groovy.util.Node. We use Node to alter the XML. We check if a FacetManager component is available. We need this to add a facet of type Spring.
When we use the IDEA plugin in Gradle we can generate IntelliJ IDEA project files. We can customise the generated files in different ways. One of them is using a simple DSL to configure certain parts of the project file. With the DSL it is easy to set the version control system (VCS) used in our project.
In the next example build file we customise the generated IDEA project file and set Git as the version control system. The property is still incubating, but we can use it to have a proper configuration.
When we run tests in IntelliJ IDEA the code is compiled by IntelliJ IDEA and the JUnit test runner is used. We get a nice graphical overview of the tasks that are executed and their results. If we use Gradle as the build tool for our project we can tell IntelliJ IDEA to always use Gradle for running tests.
We must open the Preferences or Settings dialog window. There we can search for Gradle and then look for Build, Execution, Deployment | Build Tools | Gradle | Runner:
To quickly start with a Spring project we can use the website start.spring.io.
Via a user interface we can set project properties and at the end we have a project archive (Zip or gzipped Tar file) or build file (pom.xml or build.gradle).
We can also directory access an URL to create the output files and we set the properties via request parameters.
This way you can share a link with someone and if they click on it they will download the generated project archive or build files.
We can choose different base URLs depending on the type of project archive we want.
To get a Zip file we use http://start.spring.io/starter.zip and to get a gzipped Tar file we use http://start.spring.io/starter.tgz.
To create a Gradle build file with all the configuration for a project we use http://start.spring.io/build.gradle.
For a Maven POM XML file we use the URL hhttp://start.spring.io/pom.xml.
Suppose we have a project where we use Lombok annotations. To use it we must change the compiler configuration for our project and enable annotation processing. We can find this in the Preferences or Settings window under Build, Execution, Deployment | Compiler | Annotation Processors. Here we have a checkbox Enable annotation processing that we must check to use the annotations from IntelliJ IDEA. We can automate this setting with some configuration in our Gradle build file.
In the next example build file we alter the generated IntelliJ IDEA project file using the withXml hook. We can access the generated XML as a groovy.util.Node and change the XML.
A tuple is an ordered, immutable list of elements.
Groovy has it's own groovy.lang.Tuple class.
We can create an instance of a Tuple by providing all elements that need to be in the Tuple via the constructor.
We cannot add new elements to a Tuple instance or remove elements.
We cannot even change elements in a tuple, so it is completely immutable.
This makes it very useable as return value for a method where we need to return multiple values.
Groovy also provides a Tuple2 class that can be used for tuple instance of only two elements. The elements are typed in a Tuple2 instance.
In the following example we see different uses of the Tuple and Tuple2 classes:
