Parsing and Evaluating Mathematical Formulae in Java

Overview

This repository contains the code and framework developed as part of a thesis project aimed at comparing open-source Java libraries for parsing and evaluating mathematical expressions. The project focuses on analyzing the capabilities, strengths, and limitations of these libraries.

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Objectives

The primary objective of this project is not to create a new parsing tool, but to develop a comparison framework that evaluates existing libraries based on key attributes. This framework serves as a decision-making tool to help others select the most suitable library for their needs.

The main goals of the project are:

1. Provide a generic overview of parsing and evaluating mathematical expressions.
2. Analyze at least three existing open-source libraries for mathematical expression parsing in Java.
3. Identify evaluation criteria to compare these libraries consistently.
4. Develop a comparison framework in Java to test and evaluate libraries under different scenarios.
5. Deliver practical recommendations on which library to use under specific boundary conditions.

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Libraries Studied

The project evaluates at least three popular Java libraries for parsing and evaluating mathematical expressions. Examples of libraries studied include:

• exp4j
• EvalEx
• Expr4j
• JavaMathExpressionParser
• Paralithic
• Javaluator

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Key Features of the Comparison Framework

The framework evaluates libraries based on the following attributes:

• Performance: Measures how efficiently a library parses and evaluates expressions, particularly for large and complex formulas.
• Usability: Assesses the simplicity of integration and ease of use for developers.
• Extensibility: Evaluates how well the library supports custom operators, functions, and additional features.
• Syntax Support: Tests the library’s ability to handle various mathematical constructs, including functions, constants, and operators.

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Example Use Cases

The framework provides recommendations tailored to specific scenarios, such as:

• Performance-Oriented Tasks: Selecting the fastest or most memory efficient library for real-time evaluations.
• Customization Needs: Identifying libraries that support user-defined operators or functions.
• Correctness of Evaluation: Finding the most versatile libraries, that comply with standard operator precedence and return accurate results.

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Getting Started

Setting Up the Project

1. External Libraries:
   This project uses three external libraries that were not imported through Maven, their .jar files are included in the lib folder.

   • You will need to manually add these .jar files to your project’s classpath to run the application.
     • In IntelliJ IDEA:
       1. Go to File > Project Structure > Libraries.
       2. Click + and add the .jar files from the lib folder.
     • In Eclipse:
       1. Right-click the project in the Package Explorer.
       2. Navigate to Build Path > Add External Archives, and select the .jar files.

2. Configuring the Program:
   The program execution is controlled from the Main.java file. Here, you can:

   • Select Tests: Comment out any unwanted test cases or parsing libraries that you do not wish to execute.
   • Example:

     // Comment out the unwanted tests
     orchestrator.addTest(new SpeedTest());
     orchestrator.addTest(new DataTypeTest());

3. Customizing Output:
   The output behavior can be configured using the OutputHandler class.

   • Modify the line OutputHandler.setConfig(true, true, true); in Main.java to enable or disable specific output methods:
     • First Argument: Enable/disable console output.
     • Second Argument: Enable/disable file logging.
     • Third Argument: Enable/disable data reporting filtered by test.

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Repository Structure

src/
├── main/
│   ├── java/
│   │   └── org.parser.evaluator/
│   │       ├── strategies/                     # Library-specific parsers and evaluators
│   │       │   ├── EvalEx/
│   │       │   │   ├── EvalEx.java
│   │       │   │   ├── FactorialFunction.java
│   │       │   │   └── FactorialOperator.java
│   │       │   ├── Exp4j/
│   │       │   │   └── Exp4j.java
│   │       │   ├── Expr4j/
│   │       │   │   └── Expr4j.java
│   │       │   ├── JavaMathExpressionParser/
│   │       │   │   └── JavaMathExpressionParser.java
│   │       │   ├── Paralithic/
│   │       │   │   └── Paralithic.java
│   │       │   └── IParser.java                # Interface for parser strategies
│   │       ├── testers/                        # Testing framework
│   │       │   ├── extensibility/              # Tests for extensibility
│   │       │   │   ├── ExtensibilityTest.java
│   │       │   │   └── VariableTest.java
│   │       │   ├── generator/                  # Expression generation logic
│   │       │   │   ├── ExpressionGenerator.java
│   │       │   │   └── IExpressionGenerator.java
│   │       │   ├── mathematical/               # Tests for mathematical correctness
│   │       │   │   ├── DataTypeTest.java
│   │       │   │   └── MathExpressionTest.java
│   │       │   ├── performance/                # Performance testing
│   │       │   │   ├── MemoryTest.java
│   │       │   │   └── SpeedTest.java
│   │       │   └── Test.java                   # Base test class
│   │       ├── util/                           # Utility classes
│   │       │   ├── log/
│   │       │   │   ├── report/                 # Reporting utilities
│   │       │   │   │   ├── GeneralRecorder.java
│   │       │   │   │   ├── LogContext.java
│   │       │   │   │   ├── TableReporter.java
│   │       │   │   │   └── OutputHandler.java
│   │       │   └── Orchestrator.java           # Orchestrates test runs
│   │       └── Main.java                       # Entry point for running tests
├── resources/                                  # Configuration files or sample data
└── test/                                       # Unit tests
    └── java/
        └── ExpressionGeneratorTest.java        # Test for expression generator

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Contributing

Contributions to improve the framework, expand comparisons, or add new libraries are welcome. Please open an issue or submit a pull request.

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Contact

For questions or feedback, feel free to reach out:
Lili Sebők – [email protected]