Code cleanup

.gitignore

@@ -7,3 +7,19 @@
 out/
 target
 compile/
+
+# eclipse specific git ignore
+*.pydevproject
+.project
+.metadata
+bin/**
+tmp/**
+tmp/**/*
+*.tmp
+*.bak
+*.swp
+*~.nib
+local.properties
+.classpath
+.settings/
+.loadpath

pom.xml

@@ -30,6 +30,10 @@
             <id>sk89q</id>
             <url>https://maven.sk89q.com/repo</url>
         </repository>
+        <repository>
+            <id>skript</id>
+            <url>https://repo.skriptlang.org/releases</url>
+        </repository>
     </repositories>
 
     <build>

src/main/java/com/btk5h/skriptdb/SkriptUtil.java

@@ -1,61 +1,94 @@
 package com.btk5h.skriptdb;
 
-import ch.njol.skript.Skript;
-import ch.njol.skript.lang.Expression;
-import ch.njol.skript.lang.VariableString;
-
 import java.lang.reflect.Field;
 import java.util.Arrays;
 import java.util.Optional;
 
+import org.bukkit.event.Event;
+
+import ch.njol.skript.ScriptLoader;
+import ch.njol.skript.Skript;
+import ch.njol.skript.lang.Expression;
+import ch.njol.skript.lang.VariableString;
+import ch.njol.skript.lang.parser.ParserInstance;
+
 public class SkriptUtil {
 
-  private static final Field STRING;
-  private static final Field EXPR;
+    private static final Field STRING;
+    private static final Field EXPR;
 
-  static {
-    Field _FIELD = null;
-    try {
-      _FIELD = VariableString.class.getDeclaredField("string");
-      _FIELD.setAccessible(true);
-    } catch (NoSuchFieldException e) {
-      Skript.error("Skript's 'string' field could not be resolved.");
-      e.printStackTrace();
-    }
-    STRING = _FIELD;
+    static {
+        STRING = tryGetOldStringField()
+                .or(() -> tryGetNewStringField())
+                .orElseGet(() -> {
+                    Skript.error("Skript's 'string' field could not be resolved.");
+                    return null;
+                });
 
-    try {
-      Optional<Class<?>> expressionInfo = Arrays.stream(VariableString.class.getDeclaredClasses())
-          .filter(cls -> cls.getSimpleName().equals("ExpressionInfo"))
-          .findFirst();
-      if (expressionInfo.isPresent()) {
-        Class<?> expressionInfoClass = expressionInfo.get();
-        _FIELD = expressionInfoClass.getDeclaredField("expr");
-        _FIELD.setAccessible(true);
-      } else {
-        Skript.error("Skript's 'ExpressionInfo' class could not be resolved.");
-      }
-    } catch (NoSuchFieldException e) {
-      e.printStackTrace();
-      Skript.error("Skript's 'expr' field could not be resolved.");
+        Field f = null;
+        try {
+            Optional<Class<?>> expressionInfo = Arrays.stream(VariableString.class.getDeclaredClasses())
+                    .filter(cls -> cls.getSimpleName().equals("ExpressionInfo"))
+                    .findFirst();
+            if (expressionInfo.isPresent()) {
+                Class<?> expressionInfoClass = expressionInfo.get();
+                f = expressionInfoClass.getDeclaredField("expr");
+                f.setAccessible(true);
+            } else {
+                Skript.error("Skript's 'ExpressionInfo' class could not be resolved.");
+            }
+        } catch (NoSuchFieldException e) {
+            e.printStackTrace();
+            Skript.error("Skript's 'expr' field could not be resolved.");
+        }
+        EXPR = f;
     }
-    EXPR = _FIELD;
-  }
 
-  public static Object[] getTemplateString(VariableString vs) {
-    try {
-      return (Object[]) STRING.get(vs);
-    } catch (IllegalAccessException e) {
-      throw new RuntimeException(e);
+    public static Object[] getTemplateString(VariableString vs) {
+        try {
+            return (Object[]) STRING.get(vs);
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
     }
-  }
 
-  public static Expression<?> getExpressionFromInfo(Object o) {
-    try {
-      return (Expression<?>) EXPR.get(o);
-    } catch (IllegalAccessException e) {
-      throw new RuntimeException(e);
+    public static Expression<?> getExpressionFromInfo(Object o) {
+        try {
+            return (Expression<?>) EXPR.get(o);
+        } catch (IllegalAccessException e) {
+            throw new RuntimeException(e);
+        }
+    }
+    
+    @SuppressWarnings("deprecation")
+	public static boolean isCurrentEvent(Class<? extends Event> event) {
+        try {
+            Class.forName("ch.njol.skript.lang.parser.ParserInstance");
+            return ParserInstance.get().isCurrentEvent(event);
+        } catch (ClassNotFoundException e) {
+            return ScriptLoader.isCurrentEvent(event);
+        }
+    }
+    
+    
+    private static Optional<Field> tryGetOldStringField() {
+        try {
+            Field f = VariableString.class.getDeclaredField("string");
+            f.setAccessible(true);
+            return Optional.of(f);
+        } catch (NoSuchFieldException e) {
+            return Optional.empty();
+        }
+    }
+    
+    private static Optional<Field> tryGetNewStringField() {
+        try {
+            Field f = VariableString.class.getDeclaredField("strings");
+            f.setAccessible(true);
+            return Optional.of(f);
+        } catch (NoSuchFieldException e) {
+            return Optional.empty();
+        }
     }
-  }
 
 }

src/main/java/com/btk5h/skriptdb/events/SQLQueryCompleteEvent.java

@@ -4,32 +4,26 @@ import org.bukkit.event.Event;
 import org.bukkit.event.HandlerList;
 
 public class SQLQueryCompleteEvent extends Event {
-    private final static HandlerList HANDLERS = new HandlerList();
+    
+	private static final HandlerList HANDLERS = new HandlerList();
+	
     private final String argument;
 
     public SQLQueryCompleteEvent(String argument) {
         super(true);
         this.argument = argument;
-        //  this.variables = variables;
-    }
-
-    public static HandlerList getHandlerList() {
-        return HANDLERS;
-    }
-
-    @Override
-    public String getEventName() {
-        return super.getEventName();
     }
 
     @Override
     public HandlerList getHandlers() {
-        return HANDLERS;
+        return getHandlerList();
     }
 
     public String getQuery() {
         return argument;
     }
 
-    //  public String getVariables() {return;}
+    public static HandlerList getHandlerList() {
+        return HANDLERS;
+    }
 }

src/main/java/com/btk5h/skriptdb/skript/EffExecuteStatement.java

@@ -25,6 +25,7 @@ import java.util.*;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
+import java.util.regex.Pattern;
 
 /**
  * Executes a statement on a database and optionally stores the result in a variable. Expressions
@@ -45,107 +46,85 @@ import java.util.concurrent.Executors;
  */
 public class EffExecuteStatement extends Effect {
     private static final ExecutorService threadPool = Executors.newFixedThreadPool(SkriptDB.getInstance().getConfig().getInt("thread-pool-size", 10));
+    private static final Pattern ARGUMENT_PLACEHOLDER = Pattern.compile("(?<!\\\\)\\?");
     static String lastError;
 
     static {
         Skript.registerEffect(EffExecuteStatement.class,
-                "execute %string% (in|on) %datasource% " +
-                        "[and store [[the] (output|result)[s]] (to|in) [the] [var[iable]] %-objects%]", "quickly execute %string% (in|on) %datasource% " +
-                        "[and store [[the] (output|result)[s]] (to|in) [the] [var[iable]] %-objects%]");
+                "[quickly:quickly] execute %string% (in|on) %datasource% " +
+                        "[with arg[ument][s] %-objects%] [and store [[the] (output|result)[s]] (to|in) [the] [var[iable]] %-objects%]");
     }
 
     private Expression<String> query;
     private Expression<HikariDataSource> dataSource;
-    private VariableString var;
+    private Expression<Object> queryArguments;
+    private VariableString resultVariableName;
     private boolean isLocal;
     private boolean isList;
     private boolean quickly;
     private boolean isSync = false;
 
-    private void continueScriptExecution(Event e, Object populatedVariables) {
-        lastError = null;
-        if (populatedVariables instanceof String) {
-            lastError = (String) populatedVariables;
-        } else {
-
-            if (getNext() != null) {
-                ((Map<String, Object>) populatedVariables).forEach((name, value) -> setVariable(e, name, value));
-            }
-        }
-        TriggerItem.walk(getNext(), e);
-    }
-
     @Override
     protected void execute(Event e) {
         DataSource ds = dataSource.getSingle(e);
-        Pair<String, List<Object>> query = parseQuery(e);
-        String baseVariable = var != null ? var.toString(e).toLowerCase(Locale.ENGLISH) : null;
         //if data source isn't set
-        if (ds == null) return;
+        if (ds == null) {
+        	return;
+        }
+        Pair<String, List<Object>> parsedQuery = parseQuery(e);
+        String baseVariable = resultVariableName != null ? resultVariableName.toString(e).toLowerCase(Locale.ENGLISH) : null;
+        
         Object locals = Variables.removeLocals(e);
 
         //execute SQL statement
         if (Bukkit.isPrimaryThread()) {
-            CompletableFuture<Object> sql = CompletableFuture.supplyAsync(() -> executeStatement(ds, baseVariable, query), threadPool);
-            sql.whenComplete((res, err) -> {
-                if (err != null) {
-                    err.printStackTrace();
-                }
-                //handle last error syntax data
-                lastError = null;
-                if (res instanceof String) {
-                    lastError = (String) res;
-                }
-                //if local variables are present
-                //bring back local variables
-                //populate SQL data into variables
-                if (!quickly) {
-                    Bukkit.getScheduler().runTask(SkriptDB.getInstance(), () -> {
-                        if (locals != null && getNext() != null) {
-                            Variables.setLocalVariables(e, locals);
-                        }
-                        if (!(res instanceof String)) {
-                            ((Map<String, Object>) res).forEach((name, value) -> setVariable(e, name, value));
-                        }
-                        TriggerItem.walk(getNext(), e);
-                        //the line below is required to prevent memory leaks
-                        Variables.removeLocals(e);
-                    });
-                } else {
-                    if (locals != null && getNext() != null) {
-                        Variables.setLocalVariables(e, locals);
-                    }
-                    if (!(res instanceof String)) {
-                        ((Map<String, Object>) res).forEach((name, value) -> setVariable(e, name, value));
-                    }
-                    TriggerItem.walk(getNext(), e);
-                    //the line below is required to prevent memory leaks
-                    Variables.removeLocals(e);
-                }
-            });
+            CompletableFuture.supplyAsync(() -> executeStatement(ds, baseVariable, parsedQuery), threadPool)
+		            .whenComplete((resources, err) -> {
+		            	//handle last error syntax data
+		            	resetLastSQLError();
+		            	if (err instanceof SkriptDBQueryException) {
+	            			setLastSQLError(err.getMessage());
+	            		}
+		                //if local variables are present
+		                //bring back local variables
+		                //populate SQL data into variables
+		                if (!quickly) {
+		                    Bukkit.getScheduler().runTask(SkriptDB.getInstance(),
+		                    		() -> postExecution(e, locals, resources));
+		                } else {
+		                	postExecution(e, locals, resources);
+		                }
+		            });
             // sync executed SQL query, same as above, just sync
         } else {
             isSync = true;
-            Object resources = executeStatement(ds, baseVariable, query);
-            //handle last error syntax data
-            lastError = null;
-            if (resources instanceof String) {
-                lastError = (String) resources;
-            }
+            Map<String, Object> resources = null;
+			try {
+                resources = executeStatement(ds, baseVariable, parsedQuery);
+                resetLastSQLError();
+			} catch (SkriptDBQueryException err) {
+	            //handle last error syntax data
+				setLastSQLError(err.getMessage());
+			}
             //if local variables are present
             //bring back local variables
             //populate SQL data into variables
-            if (locals != null && getNext() != null) {
-                Variables.setLocalVariables(e, locals);
-            }
-            if (!(resources instanceof String)) {
-                ((Map<String, Object>) resources).forEach((name, value) -> setVariable(e, name, value));
-            }
-            TriggerItem.walk(getNext(), e);
-            Variables.removeLocals(e);
+			postExecution(e, locals, resources);
         }
     }
     
+    private void postExecution(Event e, Object locals, Map<String, Object> resources) {
+    	if (locals != null && getNext() != null) {
+            Variables.setLocalVariables(e, locals);
+        }
+        if (resources != null) {
+        	resources.forEach((name, value) -> setVariable(e, name, value));
+        }
+        TriggerItem.walk(getNext(), e);
+        //the line below is required to prevent memory leaks
+        Variables.removeLocals(e);
+    }
+
     @Override
     protected TriggerItem walk(Event e) {
         debug(e, true);
@@ -157,142 +136,144 @@ public class EffExecuteStatement extends Effect {
     }
 
     private Pair<String, List<Object>> parseQuery(Event e) {
-        if (!(query instanceof VariableString)) {
-            return new Pair<>(query.getSingle(e), null);
-        }
-        VariableString q = (VariableString) query;
-        if (q.isSimple()) {
-            return new Pair<>(q.toString(e), null);
+        if (queryArguments != null) {
+            Object[] args = queryArguments.getArray(e);
+            String queryString = query.getSingle(e);
+            int queryArgCount = (int) ARGUMENT_PLACEHOLDER.matcher(queryString).results().count();
+            if (queryArgCount != args.length) {
+                Skript.warning("Your query has %d question marks, but you provided %d arguments.");
+                args = Arrays.copyOf(args, queryArgCount);
+            }
+            return new Pair<>(query.getSingle(e), List.of(args));
+        } else if (query instanceof VariableString && !((VariableString) query).isSimple()) {
+            return parseVariableQuery(e, (VariableString) query);
         }
+        return new Pair<>(query.getSingle(e), null);
+    }
     
+    private Pair<String, List<Object>> parseVariableQuery(Event e, VariableString varQuery) {
         StringBuilder sb = new StringBuilder();
-        List<Object> parameters = new ArrayList<>();
-        Object[] objects = SkriptUtil.getTemplateString(q);
+        List<Object> parameters = new LinkedList<>();
+        Object[] objects = SkriptUtil.getTemplateString(varQuery);
         
         for (int i = 0; i < objects.length; i++) {
-            Object o = objects[i];
-            if (o instanceof String) {
-                sb.append(o);
+            if (objects[i] instanceof String) {
+                sb.append(objects[i]);
             } else {
-                Expression<?> expr;
-                if (o instanceof Expression)
-                    expr = (Expression<?>) o;
-                else
-                    expr = SkriptUtil.getExpressionFromInfo(o);
-
-                String before = getString(objects, i - 1);
-                String after = getString(objects, i + 1);
-                boolean standaloneString = false;
-
-                if (before != null && after != null) {
-                    if (before.endsWith("'") && after.endsWith("'")) {
-                        standaloneString = true;
-                    }
-                }
-
+                Expression<?> expr = objects[i] instanceof Expression ? (Expression<?>) objects[i] : SkriptUtil.getExpressionFromInfo(objects[i]);
+                boolean standaloneString = isStandaloneString(objects, i);
                 Object expressionValue = expr.getSingle(e);
 
-                if (expr instanceof ExprUnsafe) {
-                    sb.append(expressionValue);
-
-                    if (standaloneString && expressionValue instanceof String) {
-                        String rawExpression = ((ExprUnsafe) expr).getRawExpression();
-                        Skript.warning(
-                                String.format("Unsafe may have been used unnecessarily. Try replacing 'unsafe %1$s' with %1$s",
-                                        rawExpression));
-                    }
-                } else {
-                    parameters.add(expressionValue);
-                    sb.append('?');
-
-                    if (standaloneString) {
-                        Skript.warning("Do not surround expressions with quotes!");
-                    }
+                Pair<String, Object> toAppend = parseExpressionQuery(expr, expressionValue, standaloneString);
+                sb.append(toAppend.getFirst());
+                if (toAppend.getSecond() != null) {
+                    parameters.add(toAppend.getSecond());
                 }
             }
         }
         return new Pair<>(sb.toString(), parameters);
     }
     
-    private Object executeStatement(DataSource ds, String baseVariable, Pair<String, List<Object>> query) {
-        if (ds == null) {
-            return "Data source is not set";
+    private Pair<String, Object> parseExpressionQuery(Expression<?> expr, Object expressionValue, boolean standaloneString) {
+        if (expr instanceof ExprUnsafe) {
+            if (standaloneString && expressionValue instanceof String) {
+                Skript.warning(
+                        String.format("Unsafe may have been used unnecessarily. Try replacing 'unsafe %1$s' with %1$s",
+                                ((ExprUnsafe) expr).getRawExpression()));
+            }
+            return new Pair<>((String) expressionValue, null);
+        } else {
+            if (standaloneString) {
+                Skript.warning("Do not surround expressions with quotes!");
+            }
+            return new Pair<>("?", expressionValue);
         }
-        Map<String, Object> variableList = new HashMap<>();
-        try (Connection conn = ds.getConnection();
-             PreparedStatement stmt = createStatement(conn, query)) {
+    }
 
-            boolean hasResultSet = stmt.execute();
+    private Map<String, Object> executeStatement(DataSource ds, String baseVariable, Pair<String, List<Object>> query) throws SkriptDBQueryException {
+        if (ds == null) {
+        	throw new SkriptDBQueryException("Data source is not set");
+        }
+        try (Connection conn = ds.getConnection()) {
+            try (PreparedStatement stmt = createStatement(conn, query)) {
+                boolean hasResultSet = stmt.execute();
 
-            if (baseVariable != null) {
-                if (isList) {
-                    baseVariable = baseVariable.substring(0, baseVariable.length() - 1);
-                }
-
-                if (hasResultSet) {
-                    CachedRowSet crs = SkriptDB.getRowSetFactory().createCachedRowSet();
-                    crs.populate(stmt.getResultSet());
-
-                    if (isList) {
-                        ResultSetMetaData meta = crs.getMetaData();
-                        int columnCount = meta.getColumnCount();
-
-                        for (int i = 1; i <= columnCount; i++) {
-                            String label = meta.getColumnLabel(i);
-                            variableList.put(baseVariable + label, label);
-                        }
-
-                        int rowNumber = 1;
-                        try {
-                            while (crs.next()) {
-                                for (int i = 1; i <= columnCount; i++) {
-                                    variableList.put(baseVariable + meta.getColumnLabel(i).toLowerCase(Locale.ENGLISH)
-                                            + Variable.SEPARATOR + rowNumber, crs.getObject(i));
-                                }
-                                rowNumber++;
-                            }
-                        } catch (SQLException ex) {
-                            return ex.getMessage();
-                        }
-                    } else {
-                        crs.last();
-                        variableList.put(baseVariable, crs.getRow());
-                    }
-                } else if (!isList) {
-                    //if no results are returned and the specified variable isn't a list variable, put the affected rows count in the variable
-                    variableList.put(baseVariable, stmt.getUpdateCount());
+                if (baseVariable != null) {
+                    return processBaseVariable(baseVariable, stmt, hasResultSet);
                 }
+                return Map.of();
             }
         } catch (SQLException ex) {
-            return ex.getMessage();
+            throw new SkriptDBQueryException(ex.getMessage());
+        }
+    }
+    
+    private Map<String, Object> processBaseVariable(String baseVariable, PreparedStatement stmt, boolean hasResultSet) throws SQLException {
+        Map<String, Object> variableList = new HashMap<>();
+        if (isList) {
+            baseVariable = baseVariable.substring(0, baseVariable.length() - 1);
+        }
+
+        if (hasResultSet) {
+            CachedRowSet crs = SkriptDB.getRowSetFactory().createCachedRowSet();
+            crs.populate(stmt.getResultSet());
+
+            if (isList) {
+                return fetchQueryResultSet(crs, baseVariable);
+            } else {
+                crs.last();
+                variableList.put(baseVariable, crs.getRow());
+            }
+        } else if (!isList) {
+            //if no results are returned and the specified variable isn't a list variable, put the affected rows count in the variable
+            return Map.of(baseVariable, stmt.getUpdateCount());
+        }
+        return Map.of();
+    }
+    
+    private Map<String, Object> fetchQueryResultSet(CachedRowSet crs, String baseVariable) throws SQLException {
+        Map<String, Object> variableList = new HashMap<>();
+        ResultSetMetaData meta = crs.getMetaData();
+        int columnCount = meta.getColumnCount();
+
+        for (int i = 1; i <= columnCount; i++) {
+            String label = meta.getColumnLabel(i);
+            variableList.put(baseVariable + label, label);
+        }
+
+        int rowNumber = 1;
+        while (crs.next()) {
+            for (int i = 1; i <= columnCount; i++) {
+                variableList.put(baseVariable + meta.getColumnLabel(i).toLowerCase(Locale.ENGLISH)
+                        + Variable.SEPARATOR + rowNumber, crs.getObject(i));
+            }
+            rowNumber++;
         }
         return variableList;
     }
 
     private PreparedStatement createStatement(Connection conn, Pair<String, List<Object>> query) throws SQLException {
         PreparedStatement stmt = conn.prepareStatement(query.getFirst());
-        List<Object> parameters = query.getSecond();
-
-        if (parameters != null) {
-            for (int i = 0; i < parameters.size(); i++) {
-                stmt.setObject(i + 1, parameters.get(i));
+        if (query.getSecond() != null) {
+            Iterator<Object> iter = query.getSecond().iterator();
+            for (int i = 1; iter.hasNext(); i++) {
+                stmt.setObject(i, iter.next());
             }
         }
 
         return stmt;
     }
     
+    private boolean isStandaloneString(Object[] objects, int index) {
+        String before = getString(objects, index - 1);
+        String after = getString(objects, index + 1);
+        return before != null && before.endsWith("'") && after != null && after.endsWith("'");
+    }
+
     private String getString(Object[] objects, int index) {
-        if (index < 0 || index >= objects.length) {
-            return null;
+        if (index >= 0 && index < objects.length && objects[index] instanceof String) {
+            return (String) objects[index];
         }
-
-        Object object = objects[index];
-
-        if (object instanceof String) {
-            return (String) object;
-        }
-
         return null;
     }
 
@@ -300,7 +281,7 @@ public class EffExecuteStatement extends Effect {
 
         //fix mediumblob and similar column types, so they return a String correctly
         if (obj != null) {
-            if (obj.getClass().getName().equals("[B")) {
+            if (obj instanceof byte[]) {
                 obj = new String((byte[]) obj);
 
                 //in some servers instead of being byte array, it appears as SerialBlob (depends on mc version, 1.12.2 is bvte array, 1.16.5 SerialBlob)
@@ -315,6 +296,14 @@ public class EffExecuteStatement extends Effect {
         Variables.setVariable(name.toLowerCase(Locale.ENGLISH), obj, e, isLocal);
     }
     
+    private static void resetLastSQLError() {
+    	lastError = null;
+    }
+    
+    private static void setLastSQLError(String error) {
+    	lastError = error;
+    }
+
     @Override
     public String toString(Event e, boolean debug) {
         return "execute " + query.toString(e, debug) + " in " + dataSource.toString(e, debug);
@@ -322,8 +311,7 @@ public class EffExecuteStatement extends Effect {
 
     @SuppressWarnings("unchecked")
     @Override
-    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed,
-                        SkriptParser.ParseResult parseResult) {
+    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
         Expression<String> statementExpr = (Expression<String>) exprs[0];
         if (statementExpr instanceof VariableString || statementExpr instanceof ExprUnsafe) {
             query = statementExpr;
@@ -334,17 +322,34 @@ public class EffExecuteStatement extends Effect {
             return false;
         }
         dataSource = (Expression<HikariDataSource>) exprs[1];
-        Expression<?> expr = exprs[2];
-        quickly = matchedPattern == 1;
-        if (expr instanceof Variable) {
-            Variable<?> varExpr = (Variable<?>) expr;
-            var = varExpr.getName();
+        if (exprs[2] != null) {
+            if (query instanceof VariableString && !((VariableString) query).isSimple()) {
+                Skript.warning("Your query string contains expresions, but you've also provided query arguments. Consider using `unsafe` keyword before your query.");
+            }
+            queryArguments = (Expression<Object>) exprs[2];
+        }
+        Expression<?> resultHolder = exprs[3];
+        quickly = parseResult.hasTag("quickly");
+        if (resultHolder instanceof Variable) {
+            Variable<?> varExpr = (Variable<?>) resultHolder;
+            resultVariableName = varExpr.getName();
             isLocal = varExpr.isLocal();
             isList = varExpr.isList();
-        } else if (expr != null) {
-            Skript.error(expr + " is not a variable");
+        } else if (resultHolder != null) {
+            Skript.error(resultHolder + " is not a variable");
             return false;
         }
         return true;
     }
+    
+    public static class SkriptDBQueryException extends RuntimeException {
+
+		private static final long serialVersionUID = -1869895286406538884L;
+		
+		public SkriptDBQueryException(String message) {
+			super(message);
+		}
+    	
+    }
+    
 }

src/main/java/com/btk5h/skriptdb/skript/ExprDataSource.java

@@ -32,8 +32,9 @@ public class ExprDataSource extends SimpleExpression<HikariDataSource> {
 
     static {
         Skript.registerExpression(ExprDataSource.class, HikariDataSource.class,
-                ExpressionType.COMBINED, "[the] data(base|[ ]source) [(of|at)] %string% " +
-                        "[with [a] [max[imum]] [connection] life[ ]time of %-timespan%] " + "[[(using|with)] [a] driver %-string%]");
+                ExpressionType.COMBINED, "[the] data(base|[ ]source) [(of|at)] %string% "
+                		+ "[with [a] [max[imum]] [connection] life[ ]time of %-timespan%] "
+                		+ "[[(using|with)] [a] driver %-string%]");
     }
 
     private Expression<String> url;
@@ -100,8 +101,7 @@ public class ExprDataSource extends SimpleExpression<HikariDataSource> {
 
     @SuppressWarnings("unchecked")
     @Override
-    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed,
-                        SkriptParser.ParseResult parseResult) {
+    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
         url = (Expression<String>) exprs[0];
         maxLifetime = (Expression<Timespan>) exprs[1];
         driver = (Expression<String>) exprs[2];

src/main/java/com/btk5h/skriptdb/skript/ExprSQLQuery.java

@@ -1,6 +1,10 @@
 package com.btk5h.skriptdb.skript;
 
-import ch.njol.skript.ScriptLoader;
+import org.bukkit.event.Event;
+
+import com.btk5h.skriptdb.SkriptUtil;
+import com.btk5h.skriptdb.events.SQLQueryCompleteEvent;
+
 import ch.njol.skript.Skript;
 import ch.njol.skript.lang.Expression;
 import ch.njol.skript.lang.ExpressionType;
@@ -8,8 +12,6 @@ import ch.njol.skript.lang.SkriptParser;
 import ch.njol.skript.lang.util.SimpleExpression;
 import ch.njol.skript.log.ErrorQuality;
 import ch.njol.util.Kleenean;
-import com.btk5h.skriptdb.events.SQLQueryCompleteEvent;
-import org.bukkit.event.Event;
 
 /**
  * Stores the error from the last executed statement, if there was one.
@@ -51,7 +53,7 @@ public class ExprSQLQuery extends SimpleExpression<String> {
 
     @Override
     public boolean init(final Expression<?>[] expressions, final int matchedPattern, final Kleenean isDelayed, final SkriptParser.ParseResult parseResult) {
-        if (!ScriptLoader.isCurrentEvent(SQLQueryCompleteEvent.class)) {
+        if (!SkriptUtil.isCurrentEvent(SQLQueryCompleteEvent.class)) {
             Skript.error("Cannot use 'sql query' outside of a complete of sql query event", ErrorQuality.SEMANTIC_ERROR);
             return false;
         }

src/main/java/com/btk5h/skriptdb/skript/ExprUnsafe.java

@@ -53,8 +53,7 @@ public class ExprUnsafe extends SimpleExpression<String> {
 
     @SuppressWarnings("unchecked")
     @Override
-    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed,
-                        SkriptParser.ParseResult parseResult) {
+    public boolean init(Expression<?>[] exprs, int matchedPattern, Kleenean isDelayed, SkriptParser.ParseResult parseResult) {
         stringExpression = (Expression<String>) exprs[0];
         rawExpression = parseResult.expr.substring("unsafe".length()).trim();
         return true;