Posts tagged groovy
How to Fetch RSS feeds into MongoDB with Groovy
May 20th
Suppose we will fetch some Amazon AWS news into a MongoDB database. These few lines made it possible with the use of Groovy and the Gmongo module:
Grails Goodness: Customize the URL Format
Dec 27th
Starting from Grails 2.0 we can change the URL format in our application. Default a camel case convention is used for the URLs. For example a controller SampleAppController with an action showSamplePage results in the following URL /sampleApp/showSamplePage.
Grails Goodness: Get GrailsApplication and ApplicationContext in GSP
Nov 28th
Several variables are injected to Groovy Server Pages (GSP) in a Grails application. Two of them are the ApplicationContext and GrailsApplication objects. They are bound to the variables applicationContext and grailsApplication.
Grails Goodness: Access Action and Controller Name in GSP
Nov 25th
In our GSP views we can see the name of the action and controller that resulted in the view. We can use this for example to show or hide certain information based on the values for the action and controller name. Grails injects the variables actionName and controllerName automatically and sets the values based on the action and controller.
Groovy Goodness: Magic Package to Add Custom MetaClass
Nov 23rd
Groovy is very dynamic. We can add methods to classes at runtime that don’t exist at compile time. We can add our own custom MetaClass at startup time of our application if we follow the magic package naming convention. The naming convention is groovy.runtime.metaclass.[package].[class]MetaClass. For example if we want to change the behavior of the java.lang.String class, then we must write a custom MetaClass with the package name groovy.runtime.metaclass.java.lang and class name StringMetaClass. We can do the same for classes we create ourselves. For example if we have a class myapp.RunApp than the custom metaclass implementation RunAppMetaClass would be in package groovy.runtime.metaclass.myapp.
Groovy Goodness: Create Simple Builders with Closures
Nov 17th
In Groovy we can use pre-defined builders like the JsonBuilder or MarkupBuilder to create data or text structures. It is very easy to create our own builder simply with closures. A node in the builder is simply a method and we can use a closure as the argument of the method to create a new level in the builder hierarchy.
Groovy Goodness: Create Our Own Script Class
Nov 17th
Groovy is a great language to write DSL implementations. The Groovy syntax allows for example to leave out parenthesis or semi colons, which results in better readable DSL (which is actually Groovy code).
Groovy Goodness: Create Our Own Script Class
Nov 17th
Groovy is a great language to write DSL implementations. The Groovy syntax allows for example to leave out parenthesis or semi colons, which results in better readable DSL (which is actually Groovy code).
Grails Goodness: Internationalize Javascript Messages with JAWR Plugin
Nov 14th
Grails has great builtin support for internationalization (i18n). The underlying Spring support for i18n is used. We can easily change for example text on views based on the user’s locale. But this only applies for the server side of our code. So we can generate the correct messages and labels based on the user’s locale on the server, but not in our Javascript code. What if we want to display a localized message in a bit of Javascript code, that is not created on the server? Why do I add this extra information ‘not created on the server’? Because we can still generate Javascript code in a view or use the gsp-resources plugin to create Javascript on the server. This code can contain the output of a localized message and can be used in Javascript. But that is not what we want for this blog post. Here we are going to reference our i18n messages from plain, non-generated Javascript code.
Groovy Goodness: Parse Date.toString() Value
Nov 10th
With Groovy 1.8.4 we can parse the output of the Date.toString() method back to a Date. For example we get the string value of a Date from an external source and want to parse it to a Date object. The format of the string must have the pattern “EEE MMM dd HH:mm:ss zzz yyyy” with the US Locale. This is used by the toString() method of the Date class.
