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Tag Archives: Google Guava

Guava Stopwatch

Guava‘s Stopwatch is another Guava class new to Guava Release 10 (as is Optional, the subject of another recent post). As its name implies, this simple class provides a method to conveniently measure time elapsed between two code points. It has several advantages over use of System.currentTimeMillis() or System.nanoTime(). I don’t focus on these advantages here, but the Javadoc documentation ...

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Guava Functions & Java 8 Lambdas

I recently read Brian Goetz’s The State of the Lambda and after reading that article I wanted to try using Java 8 lambda expressions. In his article, Brian goes on to describe interfaces that have one method as “functional” interfaces. Functional interfaces are almost always used as anonymous classes, with the ActionListener being the canonical example. These “functional” interfaces are ...

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Google Guava Cache

This Post is a continuation of my series on Google Guava, this time covering Guava Cache. Guava Cache offers more flexibility and power than either a HashMap or ConcurrentHashMap, but is not as heavy as using EHCache or Memcached (or robust for that matter, as Guava Cache operates solely in memory). The Cache interface has methods you would expect to ...

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Google Guava – Futures

This post is a continuation of my series on Google Guava, this time covering Futures. The Futures class is a collection of static utility methods for working with the Future/ListenableFuture interface. A Future is a handle to an asynchronous task, either a Runnable or Callable, that was submitted to an ExecutorService. The Future interface provides methods for: getting the results ...

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Google Guava Concurrency – ListenableFuture

In my last post I covered using the Monitor class from the com.google.common.util.concurrent package in the Guava Library. In this post I am going to continue my coverage of Guava concurrency utilities and discuss the ListenableFuture interface. A ListenableFuture extends the Future interface from the java.util.concurrent package, by adding a method that accepts a completion listener. ListenableFuture a ListenableFuture behaves ...

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Google Guava – Synchronization with Monitor

The Google Guava project is a collection of libraries that every Java developer should become familiar with. The Guava libraries cover I/O, collections, string manipulation, and concurrency just to name a few. In this post I am going to cover the Monitor class. Monitor is a synchronization construct that can be used anywhere you would use a ReentrantLock. Only one ...

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Guava’s Strings Class

In the post Checking for Null or Empty or White Space Only String in Java, I demonstrated common approaches in the Java ecosystem (standard Java, Guava, Apache Commons Lang, and Groovy) for checking whether a String is null, empty, or white space only similar to what C# supports with the String.IsNullOrWhiteSpace method. One of the approaches I showed was a ...

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Mocking with JodaTime’s DateTime and Google Guava’s Supplier

Introduction If you’re a seasoned unit tester, you’ve learned to take note when you see any code working with time, concurrency, random, persistence and disc I/O. The reason for this is that tests can be very brittle and sometimes down-right impossible to test properly. This post will show how to abstract out ‘time’ by injecting a replacement for it in ...

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RateLimiter – discovering Google Guava

RateLimiter class was recently added to Guava libraries (since 13.0) and it is already among my favourite tools. Have a look what the JavaDoc says: Let’s start from a simple example. Say we have a long running process that needs to broadcast its progress to supplied listener: def longRunning(listener: Listener) { var processed = 0 for(item <- items) { //..do ...

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