A use case

I have a form which has requirements as follow:
- There are some mandatory fields.
- Validation is triggered when changing value on each field.
- A button "Next" is enable only when all fields are entered. It turns to disabled if any field is empty.

My first approach

I defined a variable "isDisableNext" at a backend bean "Controller" for dynamically disabling/enabling the "Next" button by performing event "onValueChange", but, it had a problem:
<h:form id="personForm">
<p:outputLabel value="First Name" for="firstName"/>
<p:inputText id="firstName" value="#{person.firstName}"
required="true">
<p:ajax event="change" listener="#{controller.onValueChange}" update="nextButton"/>
</p:inputText>

<p:outputLabel value="Last Name" for="lastName"/>
<p:inputText id="lastName" value="#{person.lastName}"
required="true">
<p:ajax event="change" listener="#{controller.onValueChange}" update="nextButton"/>
</p:inputText>

<p:commandButton id="nextButton" actionListener="#{controller.onNext}" update="personForm" disabled="#{controller.isDisabledNext}"/>
</h:form>
Due to JSF lifecyle, the application code of Ajax "onValueChange" (at phase Invoke Application) is never invoked when validation failed. How could we update the value "isDisableNext"?
src: http://docs.oracle.com/javaee/5/tutorial/doc/bnaqq.html

My new approach: I don't try to update the backend bean at phase Invoke Application anymore but use custom validator

What is it? And, why is it possible?
- At phase Process Validation, it always calls my application code even when validation failed
- I handle enabling/disabling the button with JSF component tree instead of a backend bean.

The previous implementation turns to the following:
- Don't use required="true" because it won't invoke customer validators when a field's submitted value is empty. Then I need to add the "*" manually with "span class="ui-outputlabel-rfi".
- Use custom validator with "f:validator"
- Pass component button "Next" with "f:attribute" and "binding"
<h:form id="personForm">
<p:outputLabel value="First Name" for="firstName">
<span class="ui-outputlabel-rfi">*</span>
</p:outputLabel>
<p:inputText id="firstName" value="#{person.firstName}">
<p:ajax event="change" listener="#{controller.onValueChange}" update="nextButton"/>
<f:validator validatorId="requiredFieldValidator"/>
<f:attribute name="nextButton" value="#{nextButton}"/>
</p:inputText>

<p:outputLabel value="Last Name" for="lastName">
<span class="ui-outputlabel-rfi">*</span>
</p:outputLabel>
<p:inputText id="lastName" value="#{person.lastName}">
<p:ajax event="change" listener="#{controller.onValueChange}" update="nextButton"/>
    <f:validator validatorId="requiredFieldValidator"/>
<f:attribute name="nextButton" value="#{nextButton}"/>
</p:inputText>

<p:commandButton id="nextButton" actionListener="#{controller.onNext}" update="personForm" binding="#{nextButton}"/>
</h:form>

The custom validator looks like:
@FacesValidator(value = "requiredFieldValidator")
public class RequiredFieldValidator implements Validator{

public void validate(FacesContext context, UIComponent component, Object value) throws ValidatorException {
CommandButton nextButtonUi = (CommandButton) component.getAttributes().get("nextButton");
Map<String, String> requestParameterMap = context.getExternalContext().getRequestParameterMap();
String firstName = requestParameterMap.get(getClientId("firstName"));
String lastName = requestParameterMap.get(getClientId("lastName"));
if(StringUtils.isEmpty(firstName) || StringUtils.isEmpty(lastName)) {
nextButtonUi.setDisabled(true);
}else {
nextButtonUi.setDisabled(false);
}

RequestContext.getCurrentInstance().update(getClientId("nextButton"));
}

}


AngularJS - Build a custom validation directive for using multiple emails in textarea

AngularJS already supports the built-in validation with text input with type email. Something simple likes the following:
<input name="input" ng-model="email.text" required="" type="email" /> <span class="error" ng-show="myForm.input.$error.email"> Not valid email!</span> However, I used a text area and I wanted to enter some email addresses that's saparated by a comma (,). I had a short research and it looked like AngualarJS has not supported this functionality so far. Therefore, I needed to build a custom directive that I could add my own validation functions. My validation was done only on client side, so I used the$validators object.

Note that, there is the $asyncValidators object which handles asynchronous validation, such as making an$http request to the backend.

This is just my implementation on my project. In order to understand that, I supposed you already had experiences with Angular…

Creating a Chatbot with RiveScript in Java

Motivation"Artificial Intelligence (AI) is considered a major innovation that could disrupt many things. Some people even compare it to the Internet. A large investor firm predicted that some AI startups could become the next Apple, Google or Amazon within five years"
- Prof. John Vu, Carnegie Mellon University.

Using chatbots to support our daily tasks is super useful and interesting. In fact, "Jenkins CI, Jira Cloud, and Bitbucket" have been becoming must-have apps in Slack of my team these days.

There are some existing approaches for chatbots including pattern matching, algorithms, and neutral networks. RiveScript is a scripting language using "pattern matching" as a simple and powerful approach for building up a Chabot.
Architecture Actually, it was flexible to choose a programming language for the used Rivescript interpreter like Java, Go, Javascript, Python, and Perl. I went with Java.

Used Technologies and ToolsOracle JDK 1.8.0_151Apache Maven 3.5…

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Applying pipeline “tensorflow_embedding” of Rasa NLU

According to this nice article, there was a new pipeline released using a different approach from the standard one (spacy_sklearn). I wanted to give it a try to see whether it can help with improving bot’s accuracy.

After applying done, I gave an evaluation of “tensorflow_embedding”. It seemed to work better a bit. For example, I defined intents “greet” and “goodbye” with some following messages in my training data.
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