From 85073f7f5b8cc5ad6e9e7574e1065e516e295106 Mon Sep 17 00:00:00 2001
From: marhali <me@marhali.de>
Date: Tue, 22 Feb 2022 21:45:44 +0100
Subject: [PATCH] add utility method to check whether a string is valid
 hexadecimal number

---
 .../java/de/marhali/easyi18n/util/StringUtil.java    | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/main/java/de/marhali/easyi18n/util/StringUtil.java b/src/main/java/de/marhali/easyi18n/util/StringUtil.java
index 88c7ab8..6597dda 100644
--- a/src/main/java/de/marhali/easyi18n/util/StringUtil.java
+++ b/src/main/java/de/marhali/easyi18n/util/StringUtil.java
@@ -3,6 +3,7 @@ package de.marhali.easyi18n.util;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.StringWriter;
+import java.util.regex.Pattern;
 
 /**
  * String utilities
@@ -10,6 +11,17 @@ import java.io.StringWriter;
  */
 public class StringUtil {
 
+    /**
+     * Checks if the provided String represents a hexadecimal number.
+     * For example: {@code 0x100...}, {@code -0x100...} and {@code +0x100...}.
+     * @param string String to evaluate
+     * @return true if hexadecimal string otherwise false
+     */
+    public static boolean isHexString(@NotNull String string) {
+        final Pattern hexNumberPattern = Pattern.compile("[+-]?0[xX][0-9a-fA-F]+");
+        return hexNumberPattern.matcher(string).matches();
+    }
+
     /**
      * Escapes control characters for the given input string.
      * Inspired by Apache Commons (see {@link org.apache.commons.lang.StringEscapeUtils}