RegexMatcher.java

import javafx.stage.Stage;
import javafx.scene.layout.Pane;
import javafx.scene.control.TextArea;
import javafx.scene.control.Label;
import javafx.scene.text.Font;
import javafx.scene.control.Button;
import javafx.stage.FileChooser;
import javafx.scene.Scene;
import java.util.regex.Pattern;
import java.util.regex.Matcher;
import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;
import java.util.ArrayList;

public class RegexMatcher extends javafx.application.Application{
	static final TextArea regexArea = new TextArea();
	static final TextArea inputArea = new TextArea();

	@Override
	public void start(Stage primaryStage){
		primaryStage.setOnCloseRequest((event) -> System.exit(0));
		Pane root = new Pane();
		Label regexLabel = new Label("Regex:");
		regexLabel.setFont(Font.font(15));
		Label inputLabel = new Label("Input:");
		inputLabel.setFont(Font.font(15));

		Button match = new Button("Match");
		match.setFont(Font.font(15));
		match.setPrefSize(200, 40);
		match.setOnAction((event) -> {
			final String regex = regexArea.getText();
			final String input = inputArea.getText();
			if(regex.equals("") || input.equals(""))
				return;
			File matchesFile = new File( "matches.txt" );
			if(matchesFile.exists())
				matchesFile.delete();
			try(FileWriter writer = new FileWriter(matchesFile)){
				for(String e : match(regex, input))
					writer.write(e+"\r\n");
			}catch(Exception e){
				System.out.println(e);
			}
		});

		Button loadRegexFromFile = new Button("Load regex from file");
		loadRegexFromFile.setFont(Font.font(15));
		loadRegexFromFile.setPrefSize(200, 40);
		loadRegexFromFile.setOnAction((event) -> {
			FileChooser fileChooser = new FileChooser();
  			fileChooser.setTitle("Open regex file");
			fileChooser.getExtensionFilters().addAll(new FileChooser.ExtensionFilter("All Files", "*.*"));
			fileChooser.setInitialDirectory(new File("."));
			File selectedFile = fileChooser.showOpenDialog(primaryStage);
			try{
				if (selectedFile != null)
					regexArea.setText(readFile(selectedFile));
			}catch(Exception e){
				System.out.println(e);
			}
		});

		Button loadInputFromFile = new Button("Load input from file");
		loadInputFromFile.setFont(Font.font(15));
		loadInputFromFile.setPrefSize(200, 40);
		loadInputFromFile.setOnAction((event) -> {
			FileChooser fileChooser = new FileChooser();
  			fileChooser.setTitle("Open input file");
			fileChooser.getExtensionFilters().addAll(new FileChooser.ExtensionFilter("All Files", "*.*"));
			fileChooser.setInitialDirectory(new File("."));
			File selectedFile = fileChooser.showOpenDialog(primaryStage);
			try{
				if (selectedFile != null)
					inputArea.setText(readFile(selectedFile));
			}catch(Exception e){
				System.out.println(e);
			}
		});

		root.getChildren().addAll(regexLabel, regexArea, loadRegexFromFile, inputLabel, inputArea, loadInputFromFile, match);
		regexLabel.relocate(10, 20);
		regexArea.relocate(10, 45);
		loadRegexFromFile.relocate(500, 110);
		inputLabel.relocate(10, 240);
		inputArea.relocate(10, 265);
		loadInputFromFile.relocate(500, 330);
		match.relocate(140, 470);

		primaryStage.setScene(new Scene(root, 720, 530));
		primaryStage.show();
	}

	public static void main(String[] args) throws Exception{
		mylaunch(args);
	}

	public static void mylaunch(String ... args) throws Exception{
		if(args.length == 0){
			launch(args);
		}else if(args.length == 1){
			if(args[0].equalsIgnoreCase("-gui")){
				launch(args);
			}else if(args[0].equalsIgnoreCase("-help") || args[0].equalsIgnoreCase("-h")){
				System.out.println("Usage: java Application [options] [values]");
				System.out.println("Note:The first argument right after options is the regex (pattern), "+
					"the second one is the input");
				System.out.println("\t-gui: luanches the application in GUI mode");
				System.out.println("Note: -gui option comes the first one in options");
				System.out.println("\t-text: indicate that either regex or input is simple text passed through arguments");
				System.out.println("\t\texample: java Application -text -text \"\\d+\" \"input 100\"");
				System.out.println("\t-text: indicate that either regex or input is a file");
				System.out.println("\t\texample: java Application -file -file \"regex.txt\" \"input.txt\"");
				System.exit(0);
			}
		}else if(args.length == 4 || args.length == 5){
			String textValue = args[args.length-1];
			String regexValue = args[args.length-2];
			
			String regex = (contains("-gui", args, false) ?
				(args[1].equalsIgnoreCase("-text") ? args[3] : readFile(args[3])) :
				(args[0].equalsIgnoreCase("-text") ? args[2] : readFile(args[2])) );
			String input = (contains("-gui", args, false) ? 
				(args[2].equalsIgnoreCase("-text") ? args[4] : readFile(args[4])) :
				(args[1].equalsIgnoreCase("-text") ? args[3] : readFile(args[3])) );
			if(contains("-gui", args, false)){
				regexArea.setText(regex);
				inputArea.setText(input);
				launch(args);
			}else{
				File matchesFile = new File("matches.txt");
				try(FileWriter writer = new FileWriter(matchesFile)){
					for(String e : match(regex, input))
						writer.write(e+"\r\n");
				}catch(Exception e){
					System.out.println(e);
				}
				System.exit(0);
			}
		}
		System.out.println("Invalid arguments");
		System.exit(0);
	}

	static String readFile(File file) throws Exception{
		String data = "";
		try(FileReader reader = new FileReader( file )){
			int c = 0;
			while((c = reader.read()) != -1)
				data += (char)c;
		}catch(Exception e){
			System.out.println(e);
		}
		return data;
	}

	static String readFile(String fileName) throws Exception{
		return readFile(new File(fileName));
	}

	static int indexOf(String elem, String[] a, boolean caseSensitive){
		for(int i = 0;i < a.length;i++)
			if(caseSensitive){
				if(a[i].equals(elem))
					return i;
			}else{
				if(a[i].equalsIgnoreCase(elem))
					return i;
			}
		return -1;
	}

	static int lastIndexOf(String elem, String[] a, boolean caseSensitive){
		for(int i = a.length-1;i >= 0;i--)
			if(caseSensitive){
				if(a[i].equals(elem))
					return i;
			}else{
				if(a[i].equalsIgnoreCase(elem))
					return i;
			}
		return -1;
	}

	static boolean contains(String elem, String[] a, boolean caseSensitive){
		return (indexOf(elem, a, caseSensitive) != -1);
	}

	static ArrayList<String> match(String pattern, String input) {
		ArrayList<String> matches = new ArrayList<>();
		java.util.regex.Matcher m = (Pattern.compile(pattern)).matcher(input);
		int count = 0;
        while(m.find()) {
            count++;
            matches.add("group(" + count + "): "
                    + m.group());
        }
        return matches;
	}
}