I have been kicking the tires on using Gradle for my Groovy projects. I had a few stumbles along the way and wanted to share what I came up with for getting a very simple example working.

build.gradle

apply plugin: 'groovy'
version = "1.0-${new Date().format('yyyyMMdd')}"

jar {
from { configurations.compile.collect { it.isDirectory() ? it : zipTree(it) } }
}


below is the the HelloThere.groovy file located src/main/groovy/com/javazquez/HelloThere

package com.javazquez
public class HelloThere {

}


after running gradle build, I can navigate to the build/libs directory and run java -jar HelloThere-1.0-20111115.jar and get the following ouptut

Hello coders!

Gradle is a fantastic tool and I hope this article helps show the ease of getting a project set up.


(use '[clojure.contrib.duck-streams])
(def props (System/getProperties))
; Get the default Session object.
(def session (javax.mail.Session/getDefaultInstance props))

; send the email
(def transport (. session getTransport))
(. transport connect "smtp.gmail.com" 465 "sender@gmail.com" "password")
(. transport sendMessage msg (. msg getRecipients javax.mail.Message$RecipientType/TO))
(. transport close)


Just enter the following on your command line to generate the com.javazquez package

wsimport -keep -XadditionalHeaders -Xnocompile -p com.javazquez http://www.sandbox.paypal.com/wsdl/PayPalSvc.wsdl

open your favorite java editor(I used eclipse) and add the package(“com.javazquez”..created in the above command) to your new project

next, write some code to test out the APIs

package com.javazquez;

—
;binding
user=> (def Bonjour-Clojure “Welcome to functional programming”)
#’user/Bonjour-Clojure
user=> Bonjour-Clojure
“Welcome to functional programming”

;items in a list can be seperated via a comma or white space..
user=> (= [ 1 2 3] [1,2,3])
true

;count the number of consonants in a string
(defn count-consonants [string] (count ( re-seq #”[^aeiouAEIOU\s]” string )))
user=> (count-consonants “writing code is fun”)
10

;count the number of vowels in a string
(defn count-vowels [string] (count ( re-seq #”[aeiouAEIOU\s]” string )))
user=> (count-vowels “lukaskiewicz”)
5

;read a file into a list.. any suggestions on other ways are welcome
;usage (file-lines “string_path_to_file”) or to read a webpage ((file-lines “http://javazquez.com”)
(defn file-lines [file] (with-open [rdr (clojure.java.io/reader file)] ( set ( line-seq rdr))))

;view objects class
user=>(class “Im a string”)
java.lang.String

;length of string
user=>(count “I am 18 chars long”)
18

user=>(range 1 9)
(1 2 3 4 5 6 7 8 )

;repeat a digit
user=>(repeat 4 3)
(3 3 3 3)

;list comprehension
user=>(for [fruit ["apple" "orange" "grape"] ] (str fruit))
(“apple” “orange” “grape”)

;use map to create a new list… #() is a shortcut for an anonymous
user=>(map #(* 2 %1) [1 2 3 4])
(2 4 6 8 )

; also an anonymous function
user=> (map (fn [item](* 2 item)) [1 2 3 4])
(2 4 6 8 )

;simple fiter example on a list using odd?
user=> (filter odd? [1, 2,3,4,5])
(1 3 5)

;factorial using reduce
user=> (reduce * [1 2 3])
6

;if statement
user=> (if true (str “i am true”)(str “i am false”))
“i am true”

//Here is a quick groovy 1.7.4 Basic Auth Example
@Grab(group=’org.codehaus.groovy.modules.http-builder’, module=’http-builder’, version=’0.5.0′ )

def authSite = new groovyx.net.http.HTTPBuilder( ‘http://10.110.201.115/~juanvazquez/basicAuth/’ )
authSite.auth.basic ‘user’, ‘pwd’
println authSite.get( path:’testAuth.html’ )

#construct a tuple using()
t=(1,2,3)

#contruct a list using []
 lst= [1,2,4]

#iterate a string and print each character
for i in "This is a String":
	print(i)

#getting the length of a string
print ("length is",len("12345"))	

#test x is in a range
x=6
if(3< x <10 ):
	print( "I am true")
else:
	print( "I am false")

#test membership

if "2" in "1234":
	print("I am in the string")
if int("2") in [1,2,3,4]:
	print( "I am in the list")

#replication
print( "hithreetimes, "*3)

#using math class
import math
print(math.sqrt(4))

#print all methods
print(dir(math))

#named Tuples
import collections
Movie = collections.namedtuple("Movie","title rating")
collection =[Movie("Jaws", 4.0)]
collection.append(Movie("Toy Story", 5.0))
for movie in collection:
	print("I watched {0} and gave it {1} stars".format(movie.title,movie.rating))

#sequence unpacking
head, *rest = [1,2,3,4,5]
print("head is {0} and rest is {1}".format(head,rest))

#passing and unpacking parameters
def fullname(f,m,l):
	print("First Name ="+f)
	print("Middle Name ="+m)
        print("Last Name  ="l)

fakenamelist =["Homer","J","Simpson"]
fullname(*fakenamelist)		

#list comprehensions (print all odd numbers from 0 to 99)
print( [item for item in range(0,100) if item % 2])

#named parameters
def count_animals(number,*,	animal="ducks"):
	return "{0} {1}".format(number,animal)
print( count_animals(3,animal="cows"))
print( count_animals(3))

print(sorted([-1,2,-3],key=abs)) #same order

line = input("enter something.. ")
print("your line was " ,line)

I have been using python for web requests and recommend using the httplib2 library. It has a lot of really nice features.

This is a quick post that should help developers new to Ruby. It may also help out those that have been away from the language for a while. Its just a quick reference to Ruby’s variables and their respective scopes. I know I had a chart to keep it all straight when I first encountered the language.

1. @ An instance variable
2. [a-z] or _ A local variable
3. [A-Z] A constant
4. @@ A class variable
5. $ A global variable

This information is easily found on the net if you know what you are looking for. I just posted it to help make it even easier to find for those that are new to Ruby, or new to code writing .

I hacked some Groovy Code with some Java Code and came up with the following script. Hope it is useful.

DISCLAIMER:

As the title suggests, I have only been able to get this to work on my Windows XP machine, OS X didn’t like the javax.swing.TransferHandler and it appears some other operating systems have a hard time with this also.


import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.File;
import java.io.IOException;
import java.security.NoSuchAlgorithmException;
import java.util.List;
import java.awt.BorderLayout;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JLabel;
import javax.swing.JButton;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.TransferHandler.*;

f.getContentPane().add(p)
f.setSize(400,400)
f.setVisible(true)


About halfway through the project I heard about a cool new dynamic way to write Java code called Groovy. From that day on Groovy has been making my life a whole lot easier. I didn’t need all the functionality in the flickrj library, so I decide to write a few methods for my app using Groovy. The hardest part of the whole thing was figuring out how to post images to Flickr, for that, I used the flickrj code as a reference. If that source code was not available, I don’t think I would have ever figured it out. So a big thanks to all the folks working on that project!

This is not a complete API for Flickr, but should provide enough to get started.
Link to my GitHub Repo

I am using the imageTools plugin which you can read more about here

NOTE: The imageTools plugin has been criticized for its low quality of output. ImageMagick may be a better fit for you project(s). My particular project didn’t call for high quality pictures. A quick google search for “imagemagick for grails” should get you started on your way.

I am using version 1.0.3 in the example below

to install, I ran the following command from my grails application’s root directory

grails install-plugin http://www.arquetipos.co.cr/blog/files/grails-image-tools-1.0.3.zip

Domain-Class

class Picture {
byte[] imagefile
//Any other stuff you want to track

}


Controller Code for Saving an image

def save = {

imageTool.writeResult(imagepath, "JPEG")
imageTool.square()
flash.message = "Picture ${pictureInstance.id} created"
redirect(action:show,id:pictureInstance.id)
}
else {
render(view:'create',model:[pictureInstance:pictureInstance])
}
}

Code for displaying the image in both the ‘show’ and ‘list’ views

<td><img src="${createLinkTo(dir:'images', file: pictureInstance.id+'.jpg' )}" /> </td>