External Content with Groovy BuilderSupport - groovy

Question

I've built a custom builder in Groovy by extending BuilderSupport. It works well when configured like nearly every builder code sample out there:
def builder = new MyBuilder()
builder.foo {
"Some Entry" (property1:value1, property2: value2)
}
This, of course, works perfectly. The problem is that I don't want the information I'm building to be in the code. I want to have this information in a file somewhere that is read in and built into objects by the builder. I cannot figure out how to do this.
I can't even make this work by moving the simple entry around in the code.
This works:
def textClosure = { "Some Entry" (property1:value1, property2: value2) }
builder.foo(textClosure)
because textClosure is a closure.
If I do this:
def text = '"Some Entry" (property1:value1, property2: value2)'
def textClosure = { text }
builder.foo(textClosure)
the builder only gets called for the "foo" node. I've tried many variants of this, including passing the text block directly into the builder without wrapping it in a closure. They all yield the same result.
Is there some way I take a piece of arbitrary text and pass it into my builder so that it will be able to correctly parse and build it?

Answer 1

Your problem is that a String is not Groovy code. The way ConfigSlurper handles this is to compile the text into an instance of Script using GroovyClassLoader#parseClass. e.g.,
// create a Binding subclass that delegates to the builder
class MyBinding extends Binding {
def builder
Object getVariable(String name) {
return { Object... args -> builder.invokeMethod(name,args) }
}
}
// parse the script and run it against the builder
new File("foo.groovy").withInputStream { input ->
Script s = new GroovyClassLoader().parseClass(input).newInstance()
s.binding = new MyBinding(builder:builder)
s.run()
}
The subclass of Binding simply returns a closure for all variables that delegates the call to the builder. So assuming foo.groovy contains:
foo {
"Some Entry" (property1:value1, property2: value2)
}
It would be equivalent to your code above.

Answer 2

I think the problem you described is better solved with a slurper or parser.
See:
http://groovy.codehaus.org/Reading+XML+using+Groovy%27s+XmlSlurper
http://groovy.codehaus.org/Reading+XML+using+Groovy%27s+XmlParser
for XML based examples.
In your case. Given the XML file:
<foo>
<entry name='Some Entry' property1="value1" property2="value2"/>
</foo>
You could slurp it with:
def text = new File("test.xml").text
def foo = new XmlSlurper().parseText(text)
def allEntries = foo.entry
allEntries.each {
println it.#name
println it.#property1
println it.#property2
}

Answer 3

Originally, I wanted to be able to specify
"Some Entry" (property1:value1, property2: value2)
in an external file. I'm specifically trying to avoid XML and XML-like syntax to make these files easier for regular users to create and modify. My current solution uses ConfigSlurper and the file now looks like:
"Some Entry"
{
property1 = value1
property2 = value2
}
ConfigSlurper gives me a map like this:
["Some Entry":[property1:value1,property2:value2]]
It's pretty simple to use these values to create my objects, especially since I can just pass the property/value map into the constructor.