Tag Archives: java

Aug 20 2018
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Java, Problems

Building a Dating site with Neo4j – Part Eight

Up to this point we have a timeline of posts from people we want to date, but no way to interact with those people. The first step begins today as we will allow users to High Five and Low Five posts. Recall that once a user has high fived your post, you will be able to message them for up to 5 days when the high five expires. If you do not wish to message them, that’s fine, their high five gives you an additional high five to give to someone else in the hopes they message you. Remember that all users get 5 “free” High Fives a day, if they want more they have to earn them. You can get a High Five on a post that is older than 5 days, it still counts. This is needed to create the opportunity to bring back a user who hasn’t been to the dating site in a while with a High Five to an old Post. Otherwise after 5 days of inactivity, those users would be practically deleted.
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Aug 16 2018
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Java, Problems

Building a Dating site with Neo4j – Part Seven

Now it is time to create the timeline for our users. Most of the time, the user wants to see posts from people they could High Five in order to elicit a conversation. Sometimes, they want to see what their competition is doing and what kind of posts are getting responses… also who they can low five. I don’t think they don’t want to see messages from people who are not like them and don’t want to date them but I could be wrong.
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Aug 15 2018
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Java, Problems

Building a Dating site with Neo4j – Part Six

Without posts, we can’t have High Fives and that defeats the purpose of our dating site, so it’s time to let our users post things. We want to allow two types of posts, text posts and image posts. Today we’re going to focus on text posts and getting them working and we’ll deal with images in another post. The first thing we want to do is prevent users from posting bad things. So we’re going to create a PostValidator to deal with the user input:
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Jul 19 2018
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Java, Problems

Building a Dating site with Neo4j – Part Four

In the last post, we created a User model, built the login and registration pages, hooked everything up in our front end framework Jooby and got the ball rolling. I’m no designer so I am borrowing a Application Bootstrap Theme and tweaking that as we go along (if you are a designer, pull requests are welcomed). At this stage a ton of it is just mockup, but we will replace it with real functionality. This is what we have so far:
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Jul 12 2018
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Java, Problems

Building a Dating site with Neo4j – Part Three

We started our back end service in the last blog post and created a schema and the ability to create and fetch users. We are going to flip to the front end to make use of these abilities and work on both side by side. The goal this time is to be able to register and sign in a user. If you are a regular reader you know I’m a fan of the Jooby framework, so we’re going to use that again. After creating a shell application, what I want to do is to be able to connect to the API we’re building, so we’ll be using Retrofit to turn our HTTP API into a Java interface.
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Jul 12 2018
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Java, Problems, Testing

Building a Dating site with Neo4j – Part Two

We came up with an idea for a dating site and an initial model in Part One. Next we are going to work on a back end HTTP API, because I’m old school and that’s the way I like it. We will build our HTTP API right into Neo4j using an extension which turns Neo4j from a Server into a Service. Unlike last time where we wrote a clone of Twitter, I don’t really know where I’m going with this, so let’s start with some of the obvious API endpoints and then we can design and build more as we go along. Is this Agile or am I just being an idiot? I can’t tell, so onward we go.
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May 30 2018
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Java, Problems

Transmuting Documents into Graphs

Alchemy is a philosophical and protoscientific tradition practiced throughout Europe, Africa and Asia. Its aim is to purify, mature, and perfect certain objects. In popular culture we often see the case of shadowy figures trying to turn lead into gold to make themselves immensely rich or to ruin the world economy. In our case we will not be transmuting lead into gold, but documents into graphs which is just as good. In the past, we had used “Alchemy API” but they were purchased by IBM and retired. You can get similar functionality with IBM Watson, but let’s do something else instead. Let’s add Entity Extraction right into Neo4j.
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Feb 23 2018
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Java, Problems

Replicants

In the movie Blade Runner, “replicants” are engineered biological copies of humans. They are implanted with memories that aren’t real (to them anyway, they are sometimes the recorded memories of other people) in order to provide a sort of replacement to their emotions. The replicants are meant to work in outer space and are illegal on earth. The ones that manage to get to earth are hunted down by Deckard and other blade runners. In order to determine who is a replicant and who is a “real person” blade runners use a “Voight-Kampff” test that measures respiration, heart rate, blushing and eye movement in response to emotionally provocative questions. Today we are going to turn Neo4j into a blade runner and use it to find and retire replicated identities in our data.
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Jan 26 2018
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Java, Problems

Dynamic Rule Based Decision Trees in Neo4j – Part 2

A couple of weeks ago I showed you how to build a dynamic rule based decision tree in Neo4j. It was pretty simple and used an Expression Evaluator to determine if a set of parameters in an expression was true or false. Based on that answer it decided where to go.

But what if we had more than just true or false? What if we wanted to make our Rule nodes have more than 2 options? Today I am going to show you how to do just that… but please make sure you have read part 1 already.

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Jan 17 2018
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database, Gremlin, Java

Neptune and Uranus

Last year Microsoft announced “Cosmos DB”, a multi-modal database with graph support. I think multi-modal databases are like swiss army knifes, they can do everything, just not very well. I imagine you would design it to be as good as it can be at its main use case while not losing the ability to do other things. So it’s neither fully optimized for its main thing, nor very good at the other things. Maybe you can do pretty well with two things by making a few compromises, but if you try to do everything…it’s just not going to work out.

Can you imagine John Rambo stalking his enemies with an oversized swiss army knife? Here, let me help with the mental image:
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