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Grails Tutorial for Beginners – Criteria API

This tutorial will show how to use Criteria API to search data from the database. Criteria is a powerful API and an elegant alternative to HQL. Introduction This previous post showed that HQL is a powerful way to perform complex queries. However, it is not very elegant if an HQL statement is not fixed and needs to be concatenated. For ...

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Total Bummer: Pivotal Drops Groovy

Pivotal announced today that Groovy 2.4 And Grails 3.0 will be the last major releases under Pivotal sponsorship. This is big news that has not surprisingly created a lot of buzz in the blogosphere. In this post, I describe some of the questions that others and I are wondering about and speculate on Groovy‘s future.           ...

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Suis-je Groovy? No! What Pivotal’s Decision Means for Open Source Software

Today there was great news in the JVM ecosystem. Pivotal, the company who is committed to OSS has become a bit less committed: The reaction in the community were largely summarised by the hashtag #jesuisgroovy: Je suis groovy #groovylang — jbaruch (@jbaruch) January 19, 2015 The interesting part in Pivotal’s announcement is this one: The decision to conclude its sponsorship ...

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Grails render images on the fly in GSP

This tutorial will show how to generate PNG images on the fly and display inside a GSP. This can serve as a basis on how to create a more complex behavior. For example, creating report graphs for display in your applications. Sample Output This tutorial will show how to generate simple shapes based on input size and color. Squares and ...

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Grails Tutorial for Beginners – Grails Service Layer

This tutorial will discuss the importance of the service layer in Grails and how to work with it. It also explains transaction management and how to utilize it. Introduction Separation Of Concerns Consider this analogy: Imagine a company where employees are assigned tasks on different nature of work. For example, say there is an employee named John Doe with the ...

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Grails domain classes and special presentation requirements

In Grails we often use our domain objects directly as backing model for presentation purposes and only for specialized situations we create value holder objects or DTOs. Beginning Grails developers know how to display individual entity properties pretty easy in a GSP, such as the name of a fictional domain class…             <g:each in=”${breedingGoals}” var=”breedingGoal”> ...

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