/Cognite_Take_Home

Primary LanguageJava

T9 Texting Project README

Overview

This project recreates the T9 (Text on 9 keys) predictive text input system, reminiscent of the late 1990s cell phone technology. Users input a sequence of numbers corresponding to a standard 12-key phone dialpad, and the system generates possible word combinations. This project includes the implementation of a CodeConversion class, a functional interface for word checking, and a T9Texting class that integrates all components to find valid words from a given numeric sequence.

Implementation Details

CodeConversion Class

  • Location: T9Texting/src/main/java
  • Purpose: Generates all possible letter combinations for a given sequence of digits using a mapping of digits to letters.
  • Core Methods:
    • generateCombinations: Recursively generates letter combinations for the input sequence.
    • Accessor methods for code and map fields.

Interfaces

  • Location: T9Texting/src/main/java
  • Purpose: Contains functional interfaces used in the project.
  • Key Interfaces:
    • WordChecker: A functional interface with a single method isWord, used to determine if a string constitutes a valid word.

T9Texting Class

  • Location: T9Texting/src/main/java
  • Functionality: Serves as the entry point of the application. It simulates a T9 texting environment where users input a sequence of digits, and the system outputs all valid words as per a stubbed dictionary.
  • Key Components:
    • main: Initializes a stubbed dictionary and the digit-to-letter map, then finds and prints valid words for a given numeric sequence.
    • findWords: Uses CodeConversion to generate all possible combinations and then filters them based on validity using the provided dictionary.

How to Use

  1. Setup: Ensure Java is installed and configured on your system.
  2. Compilation: Navigate to the project directory and compile the Java files. For example, using javac T9Texting/src/main/*.java.
  3. Execution: Run the T9Texting class. For example, java T9Texting/src/main/T9Texting.
  4. Input: The main method in T9Texting class currently uses a hardcoded input sequence (4663). Modify this as needed to test different inputs.

Testing

Main Function Output

The project includes a basic stubbed dictionary for testing purposes, which considers a word valid if its length is even. For more comprehensive testing, integrate a more complex dictionary or word-checking mechanism.

JUnit Tests

  • Location: T9Texting/src/testing/java There are 2 JUnit testing files under this directory: TestCodeConversion and TestT9Texting.
TestCodeConversion
  • Functionality: Tests the object I created to make sure fields are updated correctly and the object's method's output is correct.

TestT9Texting

  • Functionality: Tests the findWords functions to make sure the output is correct given the parameters in the problem statement provided.