README.md

antlr4-file-generator

Automatically generates Java and JavaScript files based on information retrieved from a plain text file.

This is a simple Java application that uses ANTLR4 to read a raw text file and generate Java and Javascript files that basically contain the same data.

ANTLR4 is included as a maven plugin. You might choose to direcly download the jar file.

<artifactId>antlr4-maven-plugin</artifactId>

When can this be useful?

The classic example is to make sure your Java POJOs map correcly to JSon objects.

Another example is that when the frontend sends an http request, the server responds with data that both the backend and the frontend unambiguously interpret in the same way.

Before you start

Run maven clean and install.

mvn clean install

This will let ANTLR4 generate Java sources used to perform the lexing and parsing phrases on your text file, i.e. if your grammar is named Mapping.g4 then a MappingLexer.java, MappingParser.java and MappingBaseListener.java are created.
Analogously, if your grammar is math.g4, then a mathLexer.java, mathParser.java and mathBaseListener.java are created. The later goes against the Java convention of capitalizing class names, so make sure your grammar is also capitalized.

How it works?

• Edit resources/datasource.txt with the information you wish to place in your Java and JavaScript files.
  This information has to respect the rules defined in the antlr4/Mapping.g4 grammar;
• Run Generate.main() to generate the Java and JavaScript files into the output directory.

Examples

Here is a very simple example, where the resourses/datasource.txt contents is

SampleFile
================
foo = 3

The first line sets the name for the Java and Javascript files. The second line is simply a separator and finally the data section that contains only one assignment.

When you run Generate.main() the output is

Generating Java and Javascript files from resources/datasource.txt ...
Created /Users/ruisoftware/work/antlr4-file-generator/output/SampleFile.java
Created /Users/ruisoftware/work/antlr4-file-generator/output/sampleFile.js

Process finished with exit code 0

The generated Java file is placed at output/SampleFile.java

public class SampleFile {

    private static final int foo = 3;
    
}

and the correspondent JavaScript file at output/sampleFile.js

var foo = 3;

Now, let's add a more complex bar

SampleFile
================
foo = 3

bar = map (
        a = -1.2
        b = 0
        c = [2, hello, [3]]
        d = map (
              d1 = 2
              d2 = 200
           )
        e = []
    )

You can use integers, floating-point numbers, strings, maps and arrays in any combination. Arrays and maps can include other data of any type at any deepness level.
This time, the generated output/SampleFile.java is

import java.lang.Integer;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

public class SampleFile {

    private static final int foo = 3;
    
    private static final Map<String, Object> bar = new LinkedHashMap<String, Object>() {{
        put("a", new Float(-1.2f));
        put("b", new Integer(0));
        put("c", new LinkedList<Object>() {{
            add(new Integer(2));
            add("hello");
            add(new LinkedList<Integer>() {{
                add(new Integer(3));
            }});
        }});
        put("d", new LinkedHashMap<String, Integer>() {{
            put("d1", new Integer(2));
            put("d2", new Integer(200));
        }});
        put("e", new LinkedList<Object>());
    }};
    
}

and the output/sampleFile.js

var foo = 3;

var bar = {
    "a": -1.2,
    "b": 0,
    "c": [
        2,
        "hello", [3]
    ],
    "d": {
        "d1": 2,
        "d2": 200
    },
    "e": []
};

License

This project is licensed under the terms of the MIT license

Bug Reports & Feature Requests

Please use the issue tracker to report any bugs or file feature requests.