Tuesday, October 06, 2009

Converting XML to POGO

Suppose we want to convert XML to Groovy bean:

class MyBean {
String strField
float floatField
int intField
boolean boolField

def message = "<xml stringAttr='String Value' boolAttr='true' />"

def xml = new XmlSlurper().parseText(message)

def bean = new MyBean(
strField: xml.@stringAttr,
boolField: xml.@boolAttr

Everything looks good, even assertions succeed

assert 'String Value' == bean.strField
assert bean.boolField

Now let's try false value:

message = "<xml stringAttr='String Value' boolAttr='false' />"
assert !bean.boolField

Oops, the assertion failed. Why? Because xml.@boolAttr cast to boolean always returns true. The correct implementation must be like this:

message = "<xml stringAttr='String Value' floatAttr='3.14' intAttr='9' boolAttr='false' />"

xml = new XmlSlurper().parseText(message)

bean = new MyBean(
strField: xml.@stringAttr.toString(),
floatField: xml.@floatAttr.toFloat(),
intField: xml.@intAttr.toInteger(),
boolField: xml.@boolAttr.toBoolean()
assert 'String Value' == bean.strField
assert 3.14F == bean.floatField
assert 9 == bean.intField
assert !bean.boolField

Now everything works properly. The moral of this blog post: Create more unit tests (assertions), especially when you work with dynamic language.


• Converting String to Boolean

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