So this may be a more general question, but I feel it needs to be asked.
Time and time again I come across examples on Camel's documentation pages where I say "that's exactly what I want!... but it's in Java not Spring. How the heck do I convert it properly?"
So my question is: What is the rule of thumb for converting things?
Is there some conversion guide out there?
For example, I wanted to append a \n to the end of each line as the data comes through a socket into a file using the Netty4 component.
I see an example such as .transform().body(append("\n"))
How would I interpret that as Spring, to put in my Spring-based route?
Maybe this is just a thing that a person new to Camel struggles with and once you get the hang of it you can see the obvious answer. But I feel like I can't be the only one who's thinking this about the examples out there.
It seems like a lot of Java -> Spring conversion can be done in a 1 to 1 ratio, but that's not all the time.
Well, the mapping isn't straightforward and there isn't a 1-to-1 mapping available - generally, a Java DSL method invocation will in most cases translate to a tag in Spring XML DSL but the position of that tag is not always the same - in some cases Java DSL method invocation chains translate to tags being placed on the same level, sometimes (e.g. idempotent consumer) the chain translates to child tags of the first invocation.
I guess that the mapping was done this way because XML and Java are two very different languages and making the mapping 1-1 would have crippled the expressiveness of at least one, if not both, DSLs.
My advice would be to always import the XML schema and rely on your IDE's auto-completion and the documentations from the schema itself and Camel's online documentation.
You can run your camel context via mvn camel:run goal and then use a JMX client to connect to that process. There is an mbean in camel which provides a method called dumpRoutesAsXML or similar. Invoking that one will give u the xml equivalent of your context. But keep in mind that it only prints the routes and all stuff out of routes is discarded.
Hope that helps,
Lars
Related
After reading the official doc of Spring, I got this impression:
"Spring, specifically its IoC container, suits better for apps that requires only one instance of most classes".
For example we have an online shopping app. Its business logic is divided into
Order process
Payment process
and encapsulating these two parts into classes is for better code organisation rather than for implementing any functionalities, and Spring makes it easier to inject the same instance to whichever object needs it, to avoid frequent and redundant new.
However, in a Mario-like game, we might have a class Coin that requires hundreds of individual instances, and hence Spring can't be applied in this case ('cause I think #qualifier makes more mess than the good part brought by IoC).
Is the above correct?
You're correct in thinking that you wouldn't inject an object that only applies in a narrow scope.
I could see objects with Request scope that are not Singleton. Spring has supported that from the beginning.
Method scope variables should not be under Spring's control. There's nothing wrong with calling new.
You should understand Spring better before you make judgements about its efficacy.
I am working on a new project using spring data jdbc because it is very easy to handle and indeed splendid.
In my scenario i have three (maybe more in the future) types of projects. So my domain model could be easily modelled with plain old java objects using type inheritance.
First question:
As i am using spring data jdbc, is this way (inheritance) even supported like it is in JPA?
Second question - as addition to the first one:
I could not found anything regarding this within the official docs. So i am assuming there are good reasons why it is not supported. Speaking of that, may i be on the wrong track modelling entities with inheritance in general?
Currently Spring Data JDBC does not support inheritance.
The reason for this is that inheritance make things rather complicated and it was not at all clear what the correct approach is.
I have a couple of vague ideas how one might create something usable. Different repositories per type is one option, using a single type for persisting, but having some post processing to obtain the correct type upon reading is another one.
I'm working on extracting patients info in FHIR server however, I've came across two types of searching methods that were somewhat different. What is the difference between the search method of
Bundle bundle = client.seach().forResource(DiagnosticReport.class)
.
.
and
GET [base]/DiagnosticReport?result.code-value-
quantity=http://loinc.org|2823-3$gt5.4|http://unitsofmeasure.org|mmol/L
It's very confusing as it seemed that there isn't much that is mentioned about these two search methods. Can i achieve the same level of filtering with the first method compared to the url method?
The first is how to perform a search using the Java reference implementation. The latter explains what the actual HTTP query looks like that hits the server (and also specifies some additional search criteria). Behind the scenes the Java code in the first example is actually making an HTTP call that looks similar to the second example. The primary documentation in the FHIR specification deals with the HTTP call. The reference implementations work differently based on which language they are and are documented outside the FHIR specification on a reference implementation by reference implementation basis.
I'm currently using Apache UIMA to retrieve a list of occurrences of phenotype terms. However, the documentation (Why do so many bioinformatics software APIs lack good documentation!) seems to only point towards the CAS debugger GUI rather than being able to return the annotation index.
http://i.stack.imgur.com/giNoj.png - Picture of the CAS GUI, I want it to return the annotation index in the bottom left
Like I said, the docs don't really answer this (https://uima.apache.org/documentation.html), but generally I want to be able to call the process() method in the Annotator class, and for it to return the annotation index once it has found any and all occurrences.
Sorry if it's a silly question with an obvious answer, I've spent three hours going through the docs so far and haven't come any closer to finding the answer, if anyone's tried integrating it into a project in a similar way and can point me in the right direction, it would be much appreciated!
The process methods change the state inside the CAS. After calling ae.process(cas) or ae.process(jcas), the annotations are stored in the CAS. Just get the annotation index from the (J)Cas.
Apache uimaFIT might also be convenient for you as it provides various "select" methods to access annotations in the (J)CAS, e.g.:
// CAS version
Type tokenType = CasUtil.getType(cas, "my.Token");
for (AnnotationFS token : CasUtil.select(cas, tokenType)) {
...
}
// JCas version
for (Token token : JCasUtil.select(jcas, Token.class)) {
...
}
More detailed information on this API can be found in the uimaFIT documentation, in particular in the sections on pipelines and on access methods.
Disclosure: I am working on Apache uimaFIT.
I would like my first Aspect in a Roo project to run the advice when a web controller starts up. But I cant get the pointcut to match.
The controllers have a class name starting Cfx. I have tried with the following form:
pointcut setBrand() : initialization(Cfx*.new (..));
before() : setBrand()
{
log.info("xxxxxxxxxxxx setting brand");
}
As well as "initialization" I have tried (from the book AspectJ Cookbook) call(Signature) with new keyword, preinitialization, staticinitialization. What is the formula?
Maybe this is related - the Roo aspects do not have this form - no pointcut for example. How are they working? Where is this documented?
Thanks
PS apologies, this is a re-post. I posted this to the Spring Roo forum but got no response. http://forum.springsource.org/showthread.php?129374-Aspect-to-trap-Controller-creation-how-to
I know next to nothing about Roo or Spring, but some AspectJ, so I am going to answer your question from an AspectJ perspective only, assuming that you are an AOP newbie (sorry if my assumption is incorrect):
If you want to do something when a class is loaded, use a staticinitialization(TypePat) pointcut.
If you want to do something when an object (instance) is created, use something like execution(ConstructorPat). The initialization is for special purposes and preinitialization is needed even more rarely. I am assuming that the first one will do for you, not knowing your exact purpose.
Further assuming that something like execution(Cfx*.new (..)) is basically the thing you want, I suggest you look at possible errors or warnings like "advice defined in ... has not been applied [Xlint:adviceDidNotMatch]", because it might just be a pointcut matching issue. Please note that the type pattern you use assumes the matched constructors are in the same package as the aspect and that they have standard visibility (not public or anything else). So unless there is a class-loading issue, maybe you just want to specify more exactly (or more generally) what you want to match. Examples:
com.bigboxco.my_app.Cfx*.new(..)
com.bigboxco..Cfx*.new(..)
public com.bigboxco..Cfx*.new(..)
!private com.bigboxco..Cfx*.new(..)
* com.bigboxco..Cfx*.new(..)
A good strategy could be trying to match one of your constructors by replicating its exact signature and using its fully qualified class name, then working on from that point to make it more general.
Update: I know you can do a web search by yourself, but anyway here are some useful links:
AspectJ quick reference
AspectJ language semantics with topics about signatures, matching etc.