I want to avoid what seems to be a huge amount of duplication that is used in most puppet examples I've seen:
class foo(
String arg1 = '',
String arg2 = '',
...
){
if arg1 != '' {
...
}
if arg2...
}
To something more pragmatic like
class foo(
String arg1 = '',
String arg2 = ''
){
# $# is like $# in POSIX shell
$#.each {|k, v| if k[v] != '' { contain $v } }
}
There isn't a construct equivalent to $# that I'm aware of, so I'd suggest putting all of the data into a hash instead of separate parameters. There isn't any validation of the parameters being performed so a single parameter with the type Hash[Enum['network', 'mail', '...'], String] would be quite equivalent to a number of fixed String parameters, i.e.
class foo(
String $pre_class,
Hash[Enum['network', 'mail'], String] $classes = {},
){
Since you don't even need the keys, using all of the contents of the hash would be enough. values() is a stdlib function.
contain(values($classes))
Class[$pre_class] -> Class[values($classes)]
If you needed to remove empty values, then use the filter() function:
$filtered_classes = $classes.filter |$type_name, $class_name| { $class_name != '' }
I should add that I don't think the given class is a very typical module. It's a profile module and is designed to be very generic and reusable - probably a more typical locally-written profile module wouldn't be configurable to this extent where class names are given as parameter values, and would have more hard-coded behaviour.
Related
I have an dynamic html file that groovy is generated from. Part of this html template format is {routeId}{groovyMap} like so
USER_FORM[name:'Dean', user:randomFunction([item:'s', day:'Tuesday'])]
or something like
USER_FORM[name: 'Dean', user: user]
I made the first example more complex. Currently, I split on ':' and validate all the keys supplied. What I would like to do is take the groovy snippet and grab all the keys and validate
1. all keys are strings
2. validate the keys against some meta data I already have
I do not care about the values at all. Currently, I split on ':' but obviously that won't work for all cases. I am worried about other complex cases I may not be thinking about.
This is for a templating engine and I prefer to failfast if possible making it easier on the user when something is wrong.
I concur with others that you want to avoid parsing directly.
If you use GroovyShell, you can dope the input string with no-op methodMissing and propertyMissing handlers. In this way, even the complex example will work.
See code below, including test-cases (extracting map string from the "USER_FORMstr" format is left to the reader).
class KeyGenerator {
// these could be "final static". omitted for brevity
def shell = new GroovyShell()
def methodMissingHandler = "def methodMissing(String name, args) {}"
def propertyMissingHandler = "def propertyMissing(String name) {}"
def generateKeys(mapStr) {
def evalInput = "${methodMissingHandler} ; " +
"${propertyMissingHandler} ; " +
"${mapStr}"
def map = shell.evaluate(evalInput)
return map.keySet()
}
}
// ------- main
def keyGenerator = new KeyGenerator()
def expected = new HashSet()
expected << "name"
expected << "user"
def mapStr = "[name:'Dean', user:randomFunction([item:'s', day:'Tuesday'])]"
assert expected == keyGenerator.generateKeys(mapStr)
def mapStr2 = "[name: 'Dean', user: user]"
assert expected == keyGenerator.generateKeys(mapStr2)
If I got you right, you can use something like:
String val = "USER_FORM[name:'Dean', user:randomFunction([item:'s', day:'Tuesday'])]"
def res = []
val.eachMatch( /[\[,] ?(\w+):/ ){ res << it[ 1 ] }
assert '[name, user, item, day]' == res.toString()
all keys are strings
When using the literal syntax for creating a Map, i.e.
Map m = [foo: 'bar']
as opposed to
Map m = new HashMap()
m.put('foo', 'bar')
the keys are always strings, even if you have a variable in scope with the same name as the key. For example, in the following snippet, the key will be the string 'foo', not the integer 6
def foo = 6
Map m = [foo: 'bar']
The only way you can create a Map using the literal syntax with a key that is not a string is if you have a variable in scope with the same name as the key and you wrap the key name in parentheses. For example, in the following snippet, the key will be the integer 6, not the string 'foo'
def foo = 6
Map m = [(foo): 'bar']
Currently, I split on ':' but obviously that won't work for all cases. I am worried about other complex cases I may not be thinking about.
Parsing a map literal using regex/string splitting seems like a bad idea as you'll likely end up badly re-implementing the Groovy lexer. Something like the following seems a better option
def mapString = '[foo: "bar"]'
Map map = Eval.me(mapString)
// now you can process the map via the Map interface, e.g.
map.keySet().toList() == ['foo']
I have seen strange code for many times:
...
private currencyFormat = NumberFormat.currencyInstance
def convert = currencyFormat.&parse
...
By strange I mean this -> .&parse. Why logical AND operator is needed and who else it can be used?
That's a method pointer
convert is now effectively a Closure which delegates to the parse method
Example
It's defined here without an example, and mrhaki did a post about it here.
And as an example showing it handles overloading, consider a class with 2 static methods:
class Test {
static void printSomething( String thing ) {
println "A:$thing"
}
static void printSomething( String thing, String thing2 ) {
println "B:$thing$thing2"
}
}
We can get a reference to the printSomething methods:
def ref = Test.&printSomething
And then we can pass it to an each call on a list of single items:
// prints A:a and A:b
[ 'a', 'b' ].each ref
Or we can pass it two items and it will pick the correct overloaded method to call:
// prints B:ab and B:cd
[ [ 'a', 'b' ], [ 'c', 'd' ] ].each ref
It's not a bit manipulation operator. The ampersand was probably chosen because that's what C's address operator uses. The idea is that you can pass around references to a method on a specific instance.
Say you have some logic like:
def stuff = null
if (condition) {
stuff = foo.doThis(a, b, c)
} else {
stuff = bar.doOther(a, b, c)
}
You can rewrite that with a method pointer like this:
def myMethod = condition ? foo.&doThis : bar.&doOther
def stuff = myMethod(a, b, c)
It doesn't mean and. It's special syntax to reuse a method as a closure. Now you can use convert in places where you can pass a closure, like grep, find or similar methods.
I have a closure to find all files with name matching a pattern and containing a given String:
def path = "path/to/logs"
def namePatten = ~/.*.log/
def contentPattern ~/.*ERROR.*/
def result = []
new File(path).eachDirRecurse { File dir ->
dir.eachFileMatch(namePattern) { File f ->
f.eachLine { String l ->
if(l.matches(contentPattern)) {
result.add(f)
return
}
}
}
But I'm pretty sure I can have something shorter (hey, else I can use plain java :) )
I have tried to find a way to write this a bit like that:
result = new File(path).eachFileRecurse.filter(filePattern).grep(contentPattern)
as I would have done using guava or similar fluent interface collection tools.
How woud you write this closure in a concise, yet still readable, manner ?
The smallest I can get it to at present is to use the File.traverse method to recursively scan the root folder:
new File( path ).traverse( nameFilter: namePattern ) { f ->
if( f.filterLine( { it ==~ contentPattern } ) as String ) result << f
}
Using filterLine returns a Writable which I convert to a String as then we can exploit the Groovy truth to see whether to add the file to result or not.
Edit:
You can also use AntBuilder to do a similar thing:
def result = new AntBuilder().fileset( dir:'path/to/logs', includes:'**/*.log' ) {
containsregexp expression:'.*ERROR.*'
}*.file
Which I tend to prefer as it generates the list in one go, rather than adding results to an already defined results list.
I'm trying to write a mini DSL for some specific task. For this purpose I've been trying to solve a problem like this below (without using parantheses):
give me 5 like romanLetter
give me 5 like word
where the first line would return "V" and the second "five"
My definitions for the first part give me 5 look like this
def give = { clos -> clos() }
def me = { clos -> [:].withDefault { it
println it}
}
and then give me 5 prints 5
The problem is how to add more metaclass methods on the right. E.g.
give me 5 like romanLetter -> prints V OR
give me 5 like word -> prints five
my intuition is that I define like as
Object.metaClass.like = {orth -> if (orth.equals("roman")){ println "V"}
else {println "five"} }
this metaClass method like works only if there is a returned value from the left to be applied to, right? I tried adding a return statement in all of the closures which are on the left side but I always receive
groovy.lang.MissingPropertyException: No such property: like
for class: com.ontotext.paces.rules.FERulesScriptTest ...
do you have an idea how shall I do?
========================================
Here is the application of what I'm asking for.
I want to make a rule as follows
add FEATURE of X opts A,B,C named Y
where add is a closure, of, opts and named are MetaClass methods (at least that's how i imagine it), X, A, B, C, Y are parameters most probably strings and FEATURE is either a MetaClass property, or a closure without arguments or a closure with arguments.
If FEATURE does not take arguments then it is enough that add takes FEATURE as argument and returns a value on which
Object.metaClass.of will be executed with parameter X
Object.metaClass.opts will be executed on the returned by OF value with parameters A, B, C
Object.metaClass.named will be executed on the returned by opts value with parameter Y
each one of these metaclass methods sets its parameter as a value in a map, which is passed to a JAVA method when named is called.
I'm not sure this is the best solution for such a problem, but it seems to me such for the moment. The problem is if FEATURE is not a property itself but a closure which takes argument (e.g. feature1 ARG1). Then
add feature1 ARG1 of X opts A,B,C named Y
and this is the case which I'm stuck with. add feature1 ARG1 is the give me 5 part and I'm trying to add the rest to it.
========================================================
EXAMPLES:
I need to have both of the following working:
add contextFeature "text" of 1,2,3 opts "upperCase" named "TO_UPPER"
add length named "LENGTH"
where in the first case by parsing the rule, whenever each metaclass method of, opts, named is called I fill in the corresponding value in the following map:
params = [feature: "text",
of: 1,2,3,
opts: "upperCase",
named: "TO_UPPER"]
ones this map is filled in, which happens when named is parsed, I call a java method
setFeature(params.of, params.named, params.opts, params.feature)
In the second case length is predefined as length = "length", params values will be only
params = [feature : length,
of: null,
opts: null,
named: "LENGTH"]
and since of is null another java method will be called which is addSurfaceFeature(params.feature, params.named). The second case is more or less streight forward, but the first one is the one I can't manage.
Thanks in advance! Iv
You can do this sort of thing... Does that get you close?
def contextFeature( type ) {
"FEATURE_$type"
}
// Testing
new IvitaParser().parse {
a = add text of 1,2,3 opts "upperCase" named "TO_UPPER"
b = add length named "LENGTH"
c = add contextFeature( "text" ) of 1,2,3 opts "upperCase" named "TO_UPPER"
}
assert a == [feature:'text', of:[1, 2, 3], opts:'upperCase', named:'TO_UPPER']
assert b == [feature:'length', of:null, opts:null, named:'LENGTH']
assert c == [feature:'FEATURE_text', of:[1, 2, 3], opts:'upperCase', named:'TO_UPPER']
// Implementation
class IvitaParser {
Map result
def parse( Closure c ) {
c.delegate = this
c.resolveMethod = Closure.DELEGATE_FIRST
c()
}
def propertyMissing( String name ) {
name
}
def add( String param ) {
result = [ feature:param, of:null, opts:null, named:null ]
this
}
def of( Object... values ) {
result.of = values
this
}
def named( String name ) {
result.named = name
result
}
def opts( String opt ) {
result.opts = opt
this
}
}
You can even get rid of the quotes on the definition:
a = add text of 1,2,3 opts upperCase named TO_UPPER
b = add length named LENGTH
As the propertyMissing method just converts unknown properties into a String of their name
I am new to groovy and I've been facing some issues understanding the each{} and eachwithindex{} statements in groovy.
Are each and eachWithIndex actually methods? If so what are the arguments that they take?
In the groovy documentation there is this certain example:
def numbers = [ 5, 7, 9, 12 ]
numbers.eachWithIndex{ num, idx -> println "$idx: $num" } //prints each index and number
Well, I see that numbers is an array. What are num and idx in the above statement? What does the -> operator do?
I do know that $idx and $num prints the value, but how is it that idx and num are automatically being associated with the index and contents of the array? What is the logic behind this? Please help.
These are plain methods but they follow quite a specific pattern - they take a Closure as their last argument. A Closure is a piece of functionality that you can pass around and call when applicable.
For example, method eachWithIndex might look like this (roughly):
void eachWithIndex(Closure operation) {
for (int i = 0; this.hasNext(); i++) {
operation(this.next(), i); // Here closure passed as parameter is being called
}
}
This approach allows one to build generic algorithms (like iteration over items) and change the concrete processing logic at runtime by passing different closures.
Regarding the parameters part, as you see in the example above we call the closure (operation) with two parameters - the current element and current index. This means that the eachWithIndex method expects to receive not just any closure but one which would accept these two parameters. From a syntax prospective one defines the parameters during closure definition like this:
{ elem, index ->
// logic
}
So -> is used to separate arguments part of closure definition from its logic. When a closure takes only one argument, its parameter definition can be omitted and then the parameter will be accessible within the closure's scope with the name it (implicit name for the first argument). For example:
[1,2,3].each {
println it
}
It could be rewritten like this:
[1,2,3].each({ elem ->
println elem
})
As you see the Groovy language adds some syntax sugar to make such constructions look prettier.
each and eachWithIndex are, amongst many others, taking so called Closure as an argument. The closure is just a piece of Groovy code wrapped in {} braces. In the code with array:
def numbers = [ 5, 7, 9, 12 ]
numbers.eachWithIndex{ num, idx -> println "$idx: $num" }
there is only one argument (closure, or more precisely: function), please note that in Groovy () braces are sometime optional. num and idx are just an optional aliases for closure (function) arguments, when we need just one argument, this is equivalent (it is implicit name of the first closure argument, very convenient):
def numbers = [ 5, 7, 9, 12 ]
numbers.each {println "$it" }
References:
http://groovy.codehaus.org/Closures
http://en.wikipedia.org/wiki/First-class_function
Normally, if you are using a functional programing language such as Groovy, you would want to avoid using each and eachWithIndex since they encourage you to modify state within the closure or do things that have side effects.
If possible, you may want to do your operations using other groovy collection methods such as .collect or .inject or findResult etc.
However, to use these for your problem, i.e print the list elements with their index, you will need to use the withIndex method on the original collection which will transform the collection to a collection of pairs of [element, index]
For example,
println(['a', 'b', 'c'].withIndex())
EachWithIndex can be used as follows:
package json
import groovy.json.*
import com.eviware.soapui.support.XmlHolder
def project = testRunner.testCase.testSuite.project
def testCase = testRunner.testCase;
def strArray = new String[200]
//Response for a step you want the json from
def response = context.expand('${Offers#Response#$[\'Data\']}').toString()
def json = new JsonSlurper().parseText(response)
//Value you want to compare with in your array
def offername = project.getPropertyValue("Offername")
log.info(offername)
Boolean flagpresent = false
Boolean flagnotpresent = false
strArray = json.Name
def id = 0;
//To find the offername in the array of offers displayed
strArray.eachWithIndex
{
name, index ->
if("${name}" != offername)
{
flagnotpresent= false;
}
else
{
id = "${index}";
flagpresent = true;
log.info("${index}.${name}")
log.info(id)
}
}