Tag: Java

Publishing Dropwizard Metrics to Kafka

This post is about combining Dropwizard metrics with Kafka to create self instrumenting applications producing durable streams of application metrics, which can be processed (and re-processed) in many ways. The solution is appealing because Kafka is increasingly popular, and therefore likely to be available infrastructure, and Dropwizard metrics likewise, being leveraged by many open source … Continue reading Publishing Dropwizard Metrics to Kafka

A Quick Look at RoaringBitmap

This article is an introduction to the data structures found in the RoaringBitmap library, which I have been making extensive use of recently. I wrote some time ago about the basic idea of bitmap indices, which are used in various databases and search engines, with the caveat that no traditional implementation is optimal across all data scenarios (in terms of … Continue reading A Quick Look at RoaringBitmap

How a Bitmap Index Works

Bitmap indices are used in various data technologies for efficient query processing. At a high level, a bitmap index can be thought of as a physical materialisation of a set of predicates over a data set, is naturally columnar and particularly good for multidimensional boolean query processing. PostgreSQL materialises a bitmap index on the fly from query … Continue reading How a Bitmap Index Works

Advanced AOP with Guice Type Listeners

There are cross-cutting concerns, or aspects, in any non-trivial program. These blocks of code tend to be repetitive, unrelated to business logic, and don't lend themselves to being factored out. If you have ever added the same statement at the start of several methods, you have encountered an aspect. For instance, audit, instrumentation, authentication, authorisation could all be … Continue reading Advanced AOP with Guice Type Listeners

Lifecycle Management with Guice Provision Listeners

Typically in a Java web application you will have services with resources which need lifecycle management - at the very least closing gracefully at shutdown. If you'd use a sledgehammer to crack a walnut, there's Spring, which will do this for you with init and destroy methods. I'll explain why I dislike Spring in another post. You … Continue reading Lifecycle Management with Guice Provision Listeners