Method parameters in findall closure are empty - groovy

There is a method in code
def createdOrders = getValuesByStatus(extractedResponse, status)
Where extractedResponse is jsonSlurper parsed result and status just string value
Method:
def getValuesByStatus(def jsonData, String status ) {
jsonData.findAll() { json->
json.responseStatus.status == status
}
}
Testing with Spock this getValuesByStatus works perfectly,
but running main application somehow results in
java.lang.NullPointerException: Cannot get property 'responseStatus' on null object
Running debug in intellij idea I can see that jsonData is not null and not empty, but breakpoint in findall closure showing that json element is null...

Just use the null safe operator:
def getValuesByStatus(def jsonData, String status ) {
jsonData.findAll { json->
json?.responseStatus?.status == status
}
}

jsonData contains null values, but in debug mode you cant see those, so null value checking in findall closure helped.

Related

Method return wrong type of value in Groovy

I'm working on a groovy method to look for a custom attribute and return the value if the key is found.
The problem is that the method is returning the type of value instead of the value.
// There is more code before, but its not involved with this issue.
def UUIDca = 'UUID'
String customAttributeValue = grabCustomAttribute(UUIDca, event_work)
appendLogfile("\n\nTest grabCustomAttribute: ${customAttributeValue}\n")
}
// Grab the Custom Message Attribute values by name
String grabCustomAttribute (String findElement, OprEvent event){
appendLogfile("""\nIN grabCustomAttribute\nElement to look: ${findElement}\n""")
def firstItem = true
if (event.customAttributes?.customAttributes?.size()) {
event.customAttributes.customAttributes.each { ca ->
// Define each CMA to catch here
appendLogfile("""\nElement: ${ca.name} - """)
appendLogfile("""Valor: ${ca.value}\n""")
if ("${ca.name}" == findElement) {
String customValue = ca.value
appendLogfile("""Custom Attribute Found\n""")
appendLogfile(customValue)
return customValue
}
}
}
}
appendLogfile is basically a print to a log file :)
This is the output I'm getting.
IN grabCustomAttribute Element to look: UUID
Element: UUID - Valor: c3bb9169-0ca3-4bcf-beb1-f94eda8ebf1a
Custom Attribute Found
c3bb9169-0ca3-4bcf-beb1-f94eda8ebf1a
Test grabCustomAttribute: [com.hp.opr.api.ws.model.event.OprCustomAttribute#940e503a]
Instead of returning the value, it returns the type of object. It's correct, but I'm looking for the value.
I believe the solution is really simple, but I'm very new to Groovy.
Any help will be appreciated.
Thanks.
In this case the return statement is for the closure, not for the method, so your method is actually returning the list that "each" is iterating over
The easiest approach you can take here is to use Groovy find method to find the element you are searching for. Something like this:
String grabCustomAttribute (String findElement, OprEvent event) {
return event.customAttributes.customAttributes?.find { ca -> ca.name == findElement }.value
}

Using find{ } on a map where the whole map is evaluated not each element

I created some mixin methods. Code and example below:
URL.metaClass.withCreds = { u, p ->
delegate.openConnection().tap {
setRequestProperty('Authorization', "Basic ${(u + ':' + p).bytes.encodeBase64()}")
}
}
URLConnection.metaClass.fetchJson = {
delegate.setRequestProperty('Accept', 'application/json')
delegate.connect()
def code = delegate.responseCode
def result = new JsonSlurper().parse(code >= 400 ? delegate.errorStream : delegate.inputStream as InputStream)
[
ok : code in (200..299),
body: result,
code: code
]
}
example usage:
new URL("$baseUrl/projects/$name").withCreds(u, p).fetchJson().find {
it.ok
}?.tap{
it.repos = getRepos(it.key).collectEntries { [(it.slug): it] }
}
}
When I dont use find(), my object is, as expected, a map with those 3 elements. When I use find it is a Map.Entry with key ok and value true
which produces this error:
groovy.lang.MissingPropertyException: No such property: ok for class: java.util.LinkedHashMap$Entry
Possible solutions: key
It occured to me when I wrote this post that it was treated the map as an iterable and thus looking at every entry which I have subsequently verified. How do I find on the whole map? I want it.ok because if it's true, I need to carry it forward
There is no such method in Groovy SDK. Map.find() runs over an entry set of the map you call method on. Based on expectation you have defined I'm guessing you are looking for a function that tests map with a given predicate and returns the map if it matches the predicate. You may add a function that does to through Map.metaClass (since you already add methods to URL and URLConnection classes). Consider following example:
Map.metaClass.continueIf = { Closure<Boolean> predicate ->
predicate(delegate) ? delegate : null
}
def map = [
ok : true,
body: '{"message": "ok"}',
code: 200
]
map.continueIf { it.ok }?.tap {
it.repos = "something"
}
println map
In this example we introduced a new method Map.continueIf(predicate) that tests if map matches given predicate and returns a null otherwise. Running above example produces following output:
[ok:true, body:{"message": "ok"}, code:200, repos:something]
If predicate is not met, map does not get modified.
Alternatively, for more strict design, you could make fetchJson() method returning an object with corresponding onSuccess() and onError() methods so you can express more clearly that you add repos when you get a successful response and optionally you create an error response otherwise.
I hope it helps.

groovy null safe operator, identifying what was null?

The null safe operator in Groovy is great for reducing code and making things more readable. We can go from this:
def customer = getCustomer(custNo)
if(!customer)
throw new Exception("Invalid customer: ${custNo}")
def policy = customer.getPolicy(policyNo)
if(!policy)
throw new Exception("Invalid policy: ${policyNo}")
def claim = policy.getClaim(claimNo)
if(!claim)
throw new Exception("Invalid claim: ${claimNo}")
..to this...
def claim = getCustomer(custNo)?.getPolicy(policyNo)?.getClaim(claimNo)
But nothing's for free; using null/safe navigation, if claim is null, it's not immediately obvious what caused it: either custNo, policyNo, or claimNo may be invalid.
We could go back and start checking what's null, but that's counterproductive, and actually, it's not even possible since intermediate objects are not stored in variables.
So the question is: Is it possible to identify what was null when chaining method calls using null/safe navigation?
UPDATE
I took another stab at this using dynamic method invocation. It takes an init target (usually a dao) to initialize the object (customer in this case), and a map containing method names as strings (with arguments as values). Using an iterator, invokeChain simply traverses the map (chain); if anything in the chain returns null, identifying the method that caused it becomes trivial.
def invokeChain = { initTarget, chain ->
def obj
chain.eachWithIndex{ it, idx ->
//init obj from dao on first iteration only,
//remaining iterations get from obj itself
obj = (!idx) ? initTarget."$it.key"(it.value) : obj?."$it.key"(it.value)
if(!obj)
throw new Exception("${it.key}(${it.value}) returned null")
}
obj
}
Usage
Mock a customer dao for initTarget...I've inserted null as return type for getClaim(), which should throw an exception.
def static getCustomer = { custNo ->
[ getPolicy: { p ->
[getClaim:{ c ->
null //"Claim #${c}"
}]
}]
}
..using invokeChain, easy as pie:
def claim = invokeChain(this, [getCustomer:123, getPolicy:456, getClaim:789])
...throws exception, as expected:
Exception in thread "main" java.lang.Exception: getClaim(789) returned null
I like this approach because it's compact, readable, and easy to use; what do you think?
I think there is no clear way to do so.
I can be wrong, will check sources later, but safe navigation is a syntax sugar for if statement.
As a hack you can wrap your code with interceptor, trace last method call inside, and then use that info to proide error message.
It will not be cheap, and will cost you some code to realize interception and some performance while running. But you can achieve something like
mayFail("getCusomer", "getPolicy", "getClaim") {
getCustomer(custNo)?.getPolicy(policyNo)?.getClaim(claimNo)
} == "getPolicy" // failed on second step
EDIT: As #tim_yates proved, ?. is a syntax sugar with if construction behind. Thanks Vorg van Geir for the link, I have copied it here, to an answer. He say, it's outdated, and it looks like he is right. I have managed to make ProxyMetaClass work(in Groovy 2.0.6), so given way isn't totally broken. Now I need to specify exact classes to intercept, and I can not find a way to catch inherited method calls.(to simply intercept java.lang.Object)
def logInterceptor = new TracingInterceptor()
logInterceptor.writer = new StringWriter()
def intProxy = ProxyMetaClass.getInstance(Integer)
def stringProxy = ProxyMetaClass.getInstance(String)
intProxy.setInterceptor(logInterceptor)
stringProxy.setInterceptor(logInterceptor)
intProxy.use {
stringProxy.use {
println(("Hello" + "world").size().hashCode())
} }
println(logInterceptor.writer.toString())
All that hell may be wrapped in some utility code, but I highly doubt in necessarity of this. Performance overhead will be awful and some boilerplate code will remain.
The game is not worth the candle.
What about attributions and asserts?
def policy = customer?.policy
def claim = policy?.claim
def number = claim?.number
assert customer, "Invalid customer"
assert policy, 'Invalid policy'
assert claim, 'Invalid claim'
UPDATE:
You already found the solution, but i'd like to contribute with an interceptor idea:
The mock:
def dao = [
getCustomer : { custNo ->
[ getPolicy: { p ->
[getClaim:{ c ->
null //"Claim #${c}"
}]
}]
}
]
The interceptor:
class MethodCallInterceptor {
def delegate
def invokeMethod(String method, args) {
def result = delegate.invokeMethod(method, args)
if (result == null) {
throw new RuntimeException("$method returned null")
}
else {
new MethodCallInterceptor(delegate: result)
}
}
def getProperty(String property ) {
delegate[ property ]
}
void setProperty(String property, value) {
delegate[ property ] = value
}
}
The test:
def interceptedDao = new MethodCallInterceptor(delegate: dao)
try {
interceptedDao.getCustomer(123).getPolicy(456).getClaim(789)
assert false
} catch (e) {
assert e.message.contains( 'getClaim returned null' )
}

How to avoid MissingPropertyException

If an object does not have a property and I am accessing the property, we get a MissingPropertyException. Can I do something similar to safe null (?.) to guard against missing properties so it doesn't throw an exception?
One option would be:
def result = obj.hasProperty( 'b' ) ? obj.b : null
Which would return null if the object doesn't have the property...
Another would be to add propertyMissing to your class like so:
def propertyMissing( name ) {
null
}
This means that any missing properties would just result in null.
You can also use try/catch
try
{ env.GERRIT_TOPIC=GERRIT_TOPIC
}
catch (e_val)
{ echo 'missing GERRIT_TOPIC'
}

HTTPBuilder get method with closure parameter return MissingMethodException

below code:
def http = new HTTPBuilder( 'http://twitter.com/statuses/' )
http.get( path: 'user_timeline.json',
query: [id:'httpbuilder', count:5] ) { resp, json ->
println resp.status
json.each { // iterate over JSON 'status' object in the response:
println it.created_at
println ' ' + it.text
}
}
Why get exception? I use the same code from http://groovy.codehaus.org/modules/http-builder/doc/json.html, it should works.
It's IDE's problem, Eclipse groovy plugin not works very well.

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