Groovy has a with method we can use to group method calls and property
access to an object. The with method accepts a closure and every method
call or property access in the closure applies to the object if
applicable. The method is part of
Groovy's extensions to the
java.lang.Object class. Let's see this with an example:
class Sample {
String username
String email
List<String> labels = []
def speakUp() { "I am $username" }
def addLabel(value) { labels << value }
}
def sample = new Sample()
sample.with {
username = 'mrhaki'
email = 'email@host.com'
println speakUp() // Output: I am mrhaki
addLabel 'Groovy'
addLabel 'Java'
}
assert 2 == sample.labels.size()
assert 'Groovy' == sample.labels[0]
assert 'Java' == sample.labels[1]
assert 'mrhaki' == sample.username
assert 'email@host.com' == sample.email
def sb = new StringBuilder()
sb.with {
append 'Just another way to add '
append 'strings to the StringBuilder '
append 'object.'
}
assert 'Just another way to add strings to the StringBuilder object.' == sb.toString()
// Another example as seen at
// http://javajeff.blogspot.com/2008/11/getting-groovy-with-with.html
def cal = Calendar.instance
cal.with {
clear()
set(YEAR, 2009)
set MONTH, SEPTEMBER
set DATE, 4
add DATE, 2
}
assert'September 6, 2009' == cal.time.format('MMMM d, yyyy')