App.java: Start adding command line option parsing

Used the following resources to see how to parse command line options
using commons-cli:

- https://reintech.io/blog/java-command-line-applications-parsing-processing-arguments
- https://commons.apache.org/proper/commons-cli/usage.html

Reusing the options from 'pdf-form-replace-font'.

1 files changed, 38 insertions, 0 deletions

diff --git a/src/main/java/com/teddywing/pdf_form_replace_font2/App.java b/src/main/java/com/teddywing/pdf_form_replace_font2/App.java
index 3c23ba6..c916f62 100644
--- a/src/main/java/com/teddywing/pdf_form_replace_font2/App.java
+++ b/src/main/java/com/teddywing/pdf_form_replace_font2/App.java
@@ -1,5 +1,12 @@
 package com.teddywing.pdf_form_replace_font2;
 
+import org.apache.commons.cli.CommandLine;
+import org.apache.commons.cli.CommandLineParser;
+import org.apache.commons.cli.DefaultParser;
+import org.apache.commons.cli.HelpFormatter;
+import org.apache.commons.cli.Options;
+import org.apache.commons.cli.ParseException;
+
 import com.itextpdf.kernel.pdf.PdfDocument;
 import com.itextpdf.kernel.pdf.PdfReader;
 import com.itextpdf.kernel.pdf.PdfWriter;
@@ -18,6 +25,37 @@ import java.util.Map;
 public class App {
 
 	public static void main(String[] args) throws IOException {
+		Options options = new Options();
+		options.addOption("f", "find", true, "original font");
+		options.addOption("r", "replace", true, "replacement font");
+		options.addOption("o", "output", true, "output file");
+
+		options.addOption("h", "help", false, "print this help menu");
+		options.addOption("V", "version", false, "show the program version");
+
+		CommandLineParser option_parser = new DefaultParser();
+		try {
+			CommandLine options_matches = option_parser.parse(options, args);
+
+			String find = options_matches.getOptionValue("find");
+			String replace = options_matches.getOptionValue("replace");
+			String output = options_matches.getOptionValue("output");
+
+			boolean should_show_help = options_matches.hasOption("help");
+			boolean should_show_version = options_matches.hasOption("version");
+
+			if (should_show_help) {
+				HelpFormatter help_formatter = new HelpFormatter();
+				help_formatter.printHelp("pdf-form-replace-font2", options);
+
+				System.exit(0);
+			}
+		}
+		catch (ParseException e) {
+			System.err.println("error: " + e.getMessage());
+			System.exit(64);
+		}
+
 		App.replacePdfFieldFont(
 			new PdfReader("f1040.pdf"),
 			new PdfWriter("f1040-courier.pdf"),