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Tag Archives: Google Guava

Google Guava BiMaps

java-interview-questions-answers

Next up on my tour of Guava, is the BiMap, another useful collection type. It’s pretty simple really, a BiMap is simply a two way map. Inverting a Map A normal java map is a set of keys and values, and you can look up values by key, very useful, eg lets say I wanted to create a (very rudimentary) ...

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Guava Splitter vs StringUtils

So I recently wrote a post about good old reliable Apache Commons StringUtils, which provoked a couple of comments, one of which was that Google Guava provides better mechanisms for joining and splitting Strings. I have to admit, this is a corner of Guava I’ve yet to explore. So thought I ought to take a closer look, and compare with ...

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Google Guava BloomFilter

When the Guava project released version 11.0, one of the new additions was the BloomFilter class. A BloomFilter is a unique data-structure used to indicate if an element is contained in a set. What makes a BloomFilter interesting is it will indicate if an element is absolutely not contained, or may be contained in a set. This property of never ...

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Google Guava EventBus and Java 7 WatchService for Event Programming

java-interview-questions-answers

This post is going to cover using the Guava EventBus to publish changes to a directory or sub-directories detected by the Java 7 WatchService. The Guava EventBus is a great way to add publish/subscribe communication to an application. The WatchService, new in the Java 7 java.nio.file package, is used to monitor a directory for changes. Since the EventBus and WatchService ...

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Google Guava MultiMaps

Guava? This is the first in a series of posts where I’ll be attempting to explain and explore Google’s awesome Guava java library. I first came across Guava whilst searching for generic versions of Apache Commons Collections – I needed a Bimap and was fed up with having to pepper my code with casts – however what I found was ...

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Google Guava EventBus for Event Programming

 It’s a given in any software application there are objects that need to share information in order to get work done. In Java applications, one way of achieving information sharing is to have event listeners, whose sole purpose is to take some action when a desired event occurs. For the most part this process works and most experienced Java developers ...

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Guava’s Collections2: Filtering and Transforming Java Collections

One of the conveniences of Groovy is the ability to easily perform filtering and transformation operations on collections via Groovy’s closure support. Guava brings filtering and transformation on collections to standard Java and that is the subject of this post. Guava’s Collections2 class features two public methods, both of which are static. The methods filter(Collection, Predicate) and transform(Collection, Function) do ...

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Guava’s Objects Class: Equals, HashCode, and ToString

If you are fortunate enough to be using JDK 7, the newly available Objects class is the obvious (at least to me) choice for implementing the ‘common’ Java object methods such as equals(Object) [with Objects.equals(Object,Object)], hashCode() [with Objects.hashCode(Object) or Objects.hash(Object…)], and toString() [with Objects.toString(Object)] to appropriately override the default Object implementations. I have written posts about using Objects class: JDK ...

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Guava Preconditions Class

Anyone who’s written much Java has probably written methods that begin with conditionals that verify either the provided parameters or the state of the object being acted upon before proceeding with the remainder of the method’s implementation. These can add verbosity to the method and sometimes, especially if there are multiple checks, can almost drown out the interesting business logic ...

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