Programming With Recursive Structures

Introduction

The goal of this lab is to practice using recursion to interact with recursively structured data. One example of a recursively structured collection is the file system of a computer. A file system is made up of directories, each of which may contain additional directories.

This short video describes the basic recursive algorithm for searching a file system: Algorithms: Recursion

Files

The following files are provided:

• DirectorySearcher.java This (unfinished) class is responsible for recursively traversing a directory tree starting from a designated directory.
• DirectoryDriver.java This is a driver class for executing the methods provided by DirectorySearcher. As it is currently written it uses a DirectorySearcher to list the contents of the current directory.

Instructions

• Download and test the two files above. Make sure you understand how the existing code works.
• Complete the recursive listDirectories method of the DirectorySearcher class. Test your finished method by modifying the driver so that it calls this method instead of listDirectory.

• Your solution should print a "/" after each directory name and indent the files four spaces under each directory. For example, if the starting path is "../PA1", the output might look like this:

PA1/
    bin/
        Letter.class
        Hand.class
        LetterTest.class
        Board.class
        PlayScrabble.class
        BoardTest.class
        HandTest.class
    .project
    .settings/
        org.eclipse.jdt.core.prefs
    .classpath
    src/
        LetterTest.java
        HandTest.java
        Letter.java
        PlayScrabble.java
        Board.java
        BoardTest.java
        Hand.java

• Complete the searchDirectories method of the DirectorySearcher class. Test your method by modifying the driver; search for different patterns to make sure it works.

• Your solution should print the path to each file that is found. (Just print the File object itself, rather than calling getName.) For example, if the search string "Board", the output might look like this:

../PA1/bin/Board.class
../PA1/bin/BoardTest.class
../PA1/src/Board.java
../PA1/src/BoardTest.java	  

Submitting

Submit your completed DirectorySearcher.java file via Autolab.