Remove the use of script engine

AreaShop/build.gradle

@@ -6,7 +6,7 @@ plugins {
 }
 
 description = 'AreaShop'
-version = '2.6.4'
+version = '2.6.5'
 
 dependencies {
     // Spigot api

AreaShop/src/main/java/me/wiefferink/areashop/AreaShop.java

@@ -648,7 +648,8 @@ public final class AreaShop extends JavaPlugin implements AreaShopInterface {
                     if (!matcher0.find()) {
                         matcher0 = VERSION_MATCHER_2.matcher(latestVersion);
                         if (!matcher0.find()) {
-                            throw new IllegalArgumentException("Invalid Versions Detected!");
+                            // FIXME log invalid version
+                            return false;
                         }
                         dual0 = true;
                     }
@@ -657,7 +658,8 @@ public final class AreaShop extends JavaPlugin implements AreaShopInterface {
                     if (!matcher1.find()) {
                         matcher1 = VERSION_MATCHER_2.matcher(currentVersion);
                         if (!matcher1.find()) {
-                            throw new IllegalArgumentException("Invalid Versions Detected!");
+                            // FIXME log invalid version
+                            return false;
                         }
                         dual1 = true;
                     }

AreaShop/src/main/java/me/wiefferink/areashop/tools/OperandParser.java

@@ -0,0 +1,152 @@
+package me.wiefferink.areashop.tools;
+
+/**
+ * Parse math from a string
+ * Adapted from:
+ * https://stackoverflow.com/questions/3422673/how-to-evaluate-a-math-expression-given-in-string-form
+ */
+public final class OperandParser {
+
+    private final String str;
+
+    private OperandParser(final String str) {
+        this.str = str;
+    }
+
+    public static double parse(final String str) throws ParseException {
+        return new OperandParser(str).parse();
+    }
+
+
+    private int pos = -1, ch;
+
+    private void nextChar() {
+        ch = (++pos < str.length()) ? str.charAt(pos) : -1;
+    }
+
+    private boolean eat(int charToEat) {
+        while (ch == ' ') nextChar();
+        if (ch == charToEat) {
+            nextChar();
+            return true;
+        }
+        return false;
+    }
+
+    private double parse() throws ParseException {
+        nextChar();
+        double x = parseExpression();
+        if (pos < str.length())
+        {
+            throw new ParseException("Unexpected: " + (char) ch);
+        }
+        return x;
+    }
+
+    // Grammar:
+    // expression = term | expression `+` term | expression `-` term
+    // term = factor | term `*` factor | term `/` factor
+    // factor = `+` factor | `-` factor | `(` expression `)`
+    //        | number | functionName factor | factor `^` factor
+
+    private double parseExpression() throws ParseException {
+        double x = parseTerm();
+        for (; ; ) {
+            if (eat('+')) {
+                // addition
+                x += parseTerm();
+            }
+            else if (eat('-')) {
+                // subtraction
+                x -= parseTerm();
+            }
+            else return x;
+        }
+    }
+
+    private double parseTerm() throws ParseException {
+        double x = parseFactor();
+        for (; ; ) {
+            if (eat('*')) {
+                // multiplication
+                x *= parseFactor();
+            }
+            else if (eat('/')) {
+                // division
+                x /= parseFactor();
+            }
+            else return x;
+        }
+    }
+
+    private double parseFactor() throws ParseException {
+        if (eat('+')) {
+            // unary plus
+            return parseFactor();
+        }
+        if (eat('-')) {
+            // unary minus
+            return -parseFactor();
+        }
+
+        double x;
+        int startPos = this.pos;
+        if (eat('(')) {
+            // parentheses
+            x = parseExpression();
+            eat(')');
+        } else if ((ch >= '0' && ch <= '9') || ch == '.') {
+            // numbers
+            while ((ch >= '0' && ch <= '9') || ch == '.') {
+                nextChar();
+            }
+            x = Double.parseDouble(str.substring(startPos, this.pos));
+        } else if (ch >= 'a' && ch <= 'z') {
+            // functions
+            while (ch >= 'a' && ch <= 'z') {
+                nextChar();
+            }
+            String func = str.substring(startPos, this.pos);
+            x = parseFactor();
+            x = switch (func) {
+                case "sqrt" -> Math.sqrt(x);
+                case "sin" -> Math.sin(Math.toRadians(x));
+                case "cos" -> Math.cos(Math.toRadians(x));
+                case "tan" -> Math.tan(Math.toRadians(x));
+                default -> throw new ParseException("Unknown function: " + func);
+            };
+        } else {
+            throw new ParseException("Unexpected: " + (char) ch);
+        }
+
+        if (eat('^')) {
+            // exponentiation
+            x = Math.pow(x, parseFactor());
+        }
+
+        return x;
+    }
+    
+    public static class ParseException extends Exception {
+
+        public ParseException() {
+        }
+
+        public ParseException(String message) {
+            super(message);
+        }
+
+        public ParseException(String message, Throwable cause) {
+            super(message, cause);
+        }
+
+        public ParseException(Throwable cause) {
+            super(cause);
+        }
+
+        public ParseException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+            super(message, cause, enableSuppression, writableStackTrace);
+        }
+    }
+
+}

AreaShop/src/main/java/me/wiefferink/areashop/tools/Utils.java

@@ -12,7 +12,10 @@ import me.wiefferink.areashop.regions.RentRegion;
 import me.wiefferink.interactivemessenger.Log;
 import me.wiefferink.interactivemessenger.processing.Message;
 import org.apache.commons.lang.exception.ExceptionUtils;
-import org.bukkit.*;
+import org.bukkit.Bukkit;
+import org.bukkit.ChatColor;
+import org.bukkit.Location;
+import org.bukkit.World;
 import org.bukkit.block.BlockFace;
 import org.bukkit.configuration.Configuration;
 import org.bukkit.configuration.ConfigurationSection;
@@ -22,10 +25,6 @@ import org.bukkit.scheduler.BukkitRunnable;
 import org.bukkit.scheduler.BukkitTask;
 import org.bukkit.util.Vector;
 
-import javax.script.ScriptEngine;
-import javax.script.ScriptEngineManager;
-import javax.script.ScriptException;
-import java.lang.reflect.Method;
 import java.math.BigDecimal;
 import java.math.RoundingMode;
 import java.util.*;
@@ -46,7 +45,6 @@ public class Utils {
     private static Set<String> weeks;
     private static Set<String> months;
     private static Set<String> years;
-    private static ScriptEngine scriptEngine;
     private static Map<Double, String> suffixes;
 
     // Not used
@@ -768,16 +766,11 @@ public class Utils {
             return Double.parseDouble(input);
         }
 
-        // Lazy init scriptEngine
-        if (scriptEngine == null) {
-            scriptEngine = new ScriptEngineManager().getEngineByName("JavaScript");
-        }
-
         // Evaluate expression
         Object result;
         try {
-            result = scriptEngine.eval(input);
-        } catch (ScriptException e) {
+            result = OperandParser.parse(input);
+        } catch (OperandParser.ParseException e) {
             AreaShop.warn("Price of region", region.getName(), "is set with an invalid expression: '" + input + "', exception:", ExceptionUtils.getStackTrace(e));
             return 99999999999.0; // High fallback for safety
         }

build.gradle

@@ -3,7 +3,7 @@ plugins {
 }
 
 group = "me.wiefferink.areashop"
-version = '2.6.4'
+version = '2.6.5'
 
 subprojects {