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This is the code for the prototype system "CodeScoop", from the CHI paper, "Interactive Extraction of Examples from Existing Code".

Want to try out the tool but don't want to set up the project dependencies? Try out the online demo!.

Getting Started

Download GitHub Atom text editor

CodeScoop is built as an add-on for the GitHub Atom text editor. Download and install Atom text editor from the download link on the Atom home page here.

Download Java 1.7

Currently, the tool depends on Java 1.7 for running Soot static analyses and for connecting to Java through the node-java package. You can download Java 1.7 from the Oracle website.

After installing the JDK, your JAVA_HOME environment variable should point to Java 1.7 instead of another version of Java. On OSX, you can do this by adding a line like this to your ~/.bashrc set the JAVA_HOME to 1.7.

export JAVA_HOME=`/usr/libexec/java_home -v 1.7`

If you're using OSX, you will also need to create a few symbolic links so that Soot can find the class definitions it expects (see soot-oss/soot#686 for context):

sudo mkdir Classes
cd Classes/
sudo ln -s ../jre/lib/rt.jar classes.jr
sudo ln -s ../jre/lib/rt.jar ui.jar

Install the CodeScoop plugin in Atom

Clone this repository locally, and install its dependencies:

git clone codescoop

cd codescoop/
npm install      # install Node dependencies

cd java/libs/
./  # install Java dependencies (e.g., Soot, etc.)

Then compile the analysis code written in Java:

cd java/        # run this from the main `codescoop` directory

Then, install CodeScoop as an Atom plugin:

apm link

Additional Dependencies

CodeScoop depends on several third-party plugins. Install them as follows:

"Script" plugin

"Script" lets you compile and run Java within Atom. We made a fork of the script package with the right text sizing and with a tweaks to the Java classpath argument. Clone the repository and install the plugin:

git clone
cd atom-script
npm install
apm link

Event logger plugin

You don't need this to run CodeScoop, but you might need it if you want to log the user interactions. If so, install this plugin with these commands:

git clone
cd atom-event-logger
npm install
apm link

Using CodeScoop

Once you have installed CodeScoop, you can test it out on a few source programs from the repository.

Open up one of these files in Atom:

  • tests/scenarios/database-use/ based on a code example from a formative study. Uses a synthetic cursor-based database API.
  • tests/scenarios/jsoup/ uses Jsoup to fetch and parse web page content, uses a file reader API to read credentials from a file, and uses a javax.mail to send a digest of the web page contents to an email address.

Each of these files may have specific setup instructions. If there are special setup instructions, they are specified in the file for that .java file. For some of programs (, you should disable stub analysis, as it takes a long time to run for programs with lots of complex objects. To disable stub analysis, comment out the line in that reads:

      stubAnalysis: new StubAnalysis codeEditorFile

If you update the file, make sure to reload the plugin by refreshing Atom (Cmd-Ctrl-Option-L).

Now, it's time to create an example! Once you have opened the .java file you want to extract code from, select a line or lines that constitute the pattern you want to share. Right click in the editor, and choose the item "Create example from selection" in the context menu.

Depending on the Java file you're working with, CodeScoop will take a few seconds (up to 30 seconds) to analyze the code before you can interact with it.

Contributing to CodeScoop

Running the unit tests

Running the Java tests

To make sure that the static analysis code is working properly:

cd java/

Coffeescript tests

Cmd-Shift-p in Atom, type specs into window, and choose run package specs

Running Soot

After following the dependency instructions above, you should be able to run Soot to generate intermediate representation. To run soot, use the following commands:

CLASSPATH=$JAVA_HOME/jre/lib/rt.jar:libs/*:. java soot.Main Example -src-prec java -f J

with the following caveats/substitutions:

  1. Substitute Example with the name of your .java file (though omit the .java extension).
  2. This file will need to be placed in the same directory as the one that you are running the command.

Explanation of those less readable options:

  • -src-prec java: runs Soot on a .java file instead of a .class file
  • -f J: produces a Jimple IR file (instead of a class)

Changing the Java code

If you like to use vi to edit the Java code, consider using the editjava script in the java/ directory. This sets up the class path to include all of the dependencies before starting vi, in case you have an integrated Linter and want to make sure it notices all your dependencies.

If you edit any of the Java files, you will need to recompile them to see the changes take effect:

cd java/    # call this from the main directory

If Atom was already open, you should probably reload the CodeScoop plugin (Cmd-Ctrl-Opt-L).

Style Guide

When possible, I use this style guide for Coffeescript:

Equality checks

When implementing equality checks, call the method equals. The method should take in another object as a parameter and return a Boolean of whether the two objects are equal.


Members of an object should only be accessed by other objects through accessors (get methods).


When defining enums, define each field as an object. This make comparisons with an equals sign use values that are exclusive to each class, instead of comparing just on the fields of the object.


Refresh atom

Ctrl-Option-Command-l (lowercase L)

Version mismatch problem

You may need to rebuild project dependencies if you see a version mismatch error in the Atom console. You can do this with a command like:

npm rebuild --runtime=electron --target=1.3.4 --disturl= --abi=49

where 1.3.4 is your electron version and 49 is the abi it's expecting. For more context, see electron-userland/electron-builder#453)

VM launch issues

If a Java VM fails to launch when using CodeScoop, you may have to update your /etc/hosts file to redirect your machine's host name to the localhost address of Here's an example of an /etc/hosts file that works for one of the contributors to this project.	localhost	broadcasthost
::1             localhost.localdomain   localhost
::1             My-MacBook-Pro.local	My-MacBook-Pro.local


A prototype text editor plugin that lets you extract snippets from existing code






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