Ted Naleid

Inspired by this question on stackoverflow, I decided to create a utility class that allowed me to determine generically what calls a closure makes (without actually letting it make any calls). This lets me see what it’s trying to do before letting it actually do it.
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This is a continuation of a sporadic set of blog posts about some practical uses for groovy metaprogramming.

Groovy Config DSL Overview

In Java, configuration is normally done with properties files. They’re kind of a pain because they’re inflexible, don’t allow executable code, and don’t easily provide a heirarchy.

Groovy greatly improves on Java by building in support for a simple configuration DSL using the ConfigSlurper. Read the rest of this article »

I gave a presentation tonight on the build-test-data grails plugin at the Groovy Users of Minnesota (GUM) meeting that was well received.

Lots of good questions from the people in attendance. Thanks to everyone for showing up.

Here’s a version of it on slideshow: Read the rest of this article »

A recent blog post, Cedric Beust asks about how to cleanly implement “soft asserts”. Soft asserts are test assertions that don’t “fail fast”. Instead, all of the assertion failures in the test method are collected and reported at the end of the test.

So far, the proposals in the comments look fairly clunky to me and include defining whole sets of new methods like “assertEqualsButContinue(“foo”, “foo”)”, chaning assertions together jQuery-style, or using lists to hold all of our assertions.

Wouldn’t it be a lot nicer if we could continue to use the same methods that we’re already using?

In groovy, enabling soft assertions is easy with a little closure magic. Read the rest of this article »

The need to add some functionality an existing method, but avoiding cutting and pasting the old implementation has come up a few times over the last week.

Sometimes, creating a subclass isn’t feasible, often because you don’t control all of the places where that class gets used. Read the rest of this article »

If you’ve ever wondered what methods a groovy class has available for you to call, all you need to do is ask the metaClass:

"foo".metaClass.methods*.name

Result:

["equals", "getClass", "hashCode", "notify", "notifyAll", "toString", "wait", "wait", 
"wait", "charAt", "codePointAt", "codePointBefore", "codePointCount", "compareTo", 
"compareTo", "compareToIgnoreCase", "concat", "contains", "contentEquals", 
"contentEquals", "copyValueOf", "copyValueOf", "endsWith", "equals", 
"equalsIgnoreCase", "format", "format", "getBytes", "getBytes",
 "getBytes", "getChars", "hashCode", "indexOf", "indexOf", "indexOf", 
"indexOf", "intern", "lastIndexOf", "lastIndexOf", "lastIndexOf", "lastIndexOf", 
"length", "matches", "offsetByCodePoints", "regionMatches", "regionMatches", 
"replace", "replace", "replaceAll", "replaceFirst", "split", "split", "startsWith",
 "startsWith", "subSequence", "substring", "substring", "toCharArray", 
"toLowerCase", "toLowerCase", "toString", "toUpperCase", "toUpperCase", 
"trim", "valueOf", "valueOf", "valueOf", "valueOf", "valueOf", "valueOf", 
"valueOf", "valueOf", "valueOf"]

There’s a lot of duplication in there, and the order is random, so I’ll often fix that like this:

"foo".metaClass.methods*.name.sort().unique()

Result:

["charAt", "codePointAt", "codePointBefore", "codePointCount", "compareTo",
 "compareToIgnoreCase", "concat", "contains", "contentEquals", "copyValueOf", 
"endsWith", "equals", "equalsIgnoreCase", "format", "getBytes", "getChars",
 "getClass", "hashCode", "indexOf", "intern", "lastIndexOf", "length", "matches", 
"notify", "notifyAll", "offsetByCodePoints", "regionMatches", "replace", "replaceAll",
 "replaceFirst", "split", "startsWith", "subSequence", "substring", "toCharArray", 
"toLowerCase", "toString", "toUpperCase", "trim", "valueOf", "wait"]

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