How would I go about overriding AbstractCassandraConfiguration to use my own function to create a schema. I would like to be able to set up a Cassandra instance using a cql script that I select at runtime.
I have tried to override CassandraSessionFactoryBean.performSchemaAction() when it is created in AbstractCassandraConfiguration.session(). This causes cqllib to fail with
java.lang.IllegalArgumentException: Superclass has no null constructors but no arguments were given
This seems to be related to how cqlib creates proxies: Superclass has no null constructors but no arguments were given
You can override getStartupScripts() in AbstractCassandraConfiguration. In there, you can do anything you want to. It's used by CassandraCqlClusterFactoryBean's executeSpecsAndScripts method (which is called in afterPropertiesSet).
Related
Sorry to all you Groovy dudes if this is a bit of a noob question.
In SOAPUI, i can create a Groovy script where i can define an arbitrary variable to the run context to retrieve at a later time.
context.previouslyUndefinedVariable = 3
def num = context.previouslyUndefinedVariable
What feature of Groovy allows previously undefined variables to be added to an object like this? I would like to learn more about it.
Many thanks in advance!
Groovy has the ability to dynamically add methods to a class through metaprogramming.
To learn more, see:
What is Groovy's MetaClass used for?
Groovy Goodness: Add Methods Dynamically to Classes with ExpandoMetaClass
Runtime and compile-time metaprogramming
The accepted answer is a bit of a poor explanation for how SoapUI is doing it.
In this case, context is always an instance of some SoapUI library java class (such as WsdlTestRunContext), and these are all implementations of Map. You can check context.getClass() and assert context in Map.
When you look up a property on a Map, Groovy uses the getAt and putAt methods. There are various syntaxes you can use. All of these are equivalent:
context.someUndef
context.'someUndef'
context[someUndef]
context['someUndef']
context.getAt('someUndef')
And
context.someUndef = 3
context.'someUndef' = 3
context[someUndef] = 3
context['someUndef'] = 3
context.putAt('someUndef', 3)
I like to use any of the above that include quote marks, so that Groovy-Eclipse doesn't flag it as a missing property.
It's also interesting that Groovy looks for a getAt() method before it checks for a get method being referred to as a property.
For example, consider evaluating "foo".class. The String instance doesn't have a property called class and it also doesn't have a method getAt(String), so the next thing it tries is to look for a "get" method with that name, i.e. getClass(), which it finds, and we get our result: String.
But with a map, ['class':'bar'].class refers to the method call getAt('class') first, which will be 'bar'. If we want to know what type of Map it is, we have to be more specific and write in full: ['class':'bar'].getClass() which will be LinkedHashMap.
We still have to specify getClass() even if that Map doesn't have a matching key, because ['foo':'bar'].class will still mean ['foo':'bar'].getAt('class'), which will be null.
I have created a class implementing GenericHandler to use in .handle() method. I have setters for the class, but if i have more than 1 setter with same argument type, i am getting "Found Ambiguous parameter type".
Why there is such restriction?
That's just because ServiceActivatingHandler is based on the MessagingMethodInvokerHelper logic on background to determine the appropriate messaging method. And setters are candidate for that purpose.
So, if you really hae several of them with the same param type, we end up with ambiguity issue.
To fix your case, I suggest mark your Object handle(P payload, Map<String, Object> headers); implementation with #ServiceActivator.
From other side I agree that it is not so good as we expect from Framework. So, feel free to raise a JIRA issue on the matter and we will fix .handle() to be more strict and rely only on the handle() method from the GenericHandler implementation.
I faced the same problem while using Spring integration while using a service adaptor. Could not define multiple properties of type java.lang.String - I would get a IllegalArgumentException claiming "ambiguous parameters".
After finding no solution to the issue, decided to just create a class to encapsulate those properties, configure this as a bean, and then inject it into the spring-integration config.
I need to run some code whenever a property value is retrieved, so naturally it made sense to define the getProperty method in my class. This method will get automatically called whenever a property value is retrieved. Here's roughly what I have in my class:
class MyClass
{
def getProperty(String name)
{
// Run some code ...
return this.#"${name}"
}
}
The problem with the above method occurs when someone tries to make the following call somewhere:
MyClass.class
This call ends up in the getProperty method looking for a property named "class", however, there is not actual property named "class" so we get a MissingFieldException.
What would be the correct way to implement running code whenever a property value is retrieved and deal with these kind of situtations.
Best is not to have a getProperty method if not needed. If you need one and you want to fall back on standard Groovy logic, then you can use return getMetaClass().getProperty(this, property), as can be found in GroovyObjectSupport. This will cover more than just fields.
This seems to be a common problem with this method. Map has the same issue. The developers of groovy got around the problem with Map by saying you need to use getClass() directly.
How can we add some common constraints (i.e. maxLength, nullable) to a property of a Groovy class? I know we can do it at Grails domain class, but is it possible if that is a Groovy class (I use it as a DTO class for my Grails project)?
Thank you so much!
You can add constraints to command classes. If a command class is in the same .groovy file as a controller (in Groovy you can have more than one public class in each .groovy file), you don't need to do anything special for Grails to recongise it as a command class.
However, if your command class is somewhere else (e.g. under src/groovy), you need to annotate it with #Validateable and add the package name to the grails.validateable.packages parameter in Config.groovy. Here's an example of a command that's not in the same file as a controller
pacakge com.example.command
#Validateable
class Person {
Integer age
String name
static constraints = {
name(blank: false)
age(size 0..100)
}
}
Add the following to Config.groovy
grails.validateable.packages = ['com.example.command']
Command classes have a validate() method added by Grails. After this method is called, any errors will be available in the errors property (as per domain classes).
Using a grails Command Object is probably your best bet. It has constraints and validation, but no database backing. It's normally a value object that controllers use, but you could instantiate one outside of a controller without any problems.
Not sure if this is relevant to your use (I am not familiar with DTOs), but in the current version (2.3.8), you can also add Grails constraints to an abstract class, and they will be inherited by the domains that extend it. Your IDE might not like it though ;)
I am using groovy to create some mock classes for a test case. I am basically creating dummy objects where all the methods return null so that i can run my testcase.
I am using the following syntax:
MessageFactory.instance = ["getMessage": {a,b,c,d -> "dummy"}] as MessageFactory
So here i am trying to overwrite the singleton instance with my on fake factory object. The problem is that MessageFactory's constructor happens to be a private method. This gives me an illigal access exception when i run the code above. Is there a away i can create a proxy in groovy and overcome the private constructor issue?
If you have access to the MessageFactory, and are willing to modify it, then you use the standard dependency-injection solution, as detailed here: mock singleton
..Though it's not particularly Groovy.
Otherwise, the best workaround I've found is to override the method(s) on the singleton instance itself, like so:
#Singleton
class Test{
def method(){"Unmocked method called"}
}
def test = Test.instance
test.metaClass.method = {-> null}
test.method() // Now returns null
Naturally, as a singleton, this instance doesn't change (at least in theory)... So, overriding methods in this manner is effectively global.
Edit: Or you can use GMock, which supports constructor mocking (among other things).