Sql triggers executing SQL, Javascript and Java code

engine/src/main/antlr4/com/arcadedb/query/sql/grammar/SQLLexer.g4

@@ -202,6 +202,7 @@ FUNCTION: F U N C T I O N;
 GLOBAL: G L O B A L;
 PARAMETERS: P A R A M E T E R S;
 LANGUAGE: L A N G U A G E;
+TRIGGER: T R I G G E R;
 FAIL: F A I L;
 FIX: F I X;
 SLEEP: S L E E P;

engine/src/main/antlr4/com/arcadedb/query/sql/grammar/SQLParser.g4

@@ -93,6 +93,7 @@ statement
     | CREATE BUCKET createBucketBody                 # createBucketStmt
     | CREATE VERTEX createVertexBody                 # createVertexStmt
     | CREATE EDGE createEdgeBody                     # createEdgeStmt
+    | CREATE TRIGGER createTriggerBody               # createTriggerStmt
 
     // DDL Statements - ALTER variants
     | ALTER TYPE alterTypeBody                       # alterTypeStmt
@@ -105,6 +106,7 @@ statement
     | DROP PROPERTY dropPropertyBody                 # dropPropertyStmt
     | DROP INDEX dropIndexBody                       # dropIndexStmt
     | DROP BUCKET dropBucketBody                     # dropBucketStmt
+    | DROP TRIGGER dropTriggerBody                   # dropTriggerStmt
 
     // DDL Statements - TRUNCATE variants
     | TRUNCATE TYPE truncateTypeBody                 # truncateTypeStmt
@@ -586,6 +588,46 @@ dropBucketBody
     : identifier (IF EXISTS)?
     ;
 
+// ============================================================================
+// TRIGGER MANAGEMENT
+// ============================================================================
+
+/**
+ * CREATE TRIGGER statement
+ * Syntax: CREATE TRIGGER [IF NOT EXISTS] name (BEFORE|AFTER) (CREATE|READ|UPDATE|DELETE)
+ *         ON [TYPE] typeName (EXECUTE SQL 'statement' | EXECUTE JAVASCRIPT 'code' | EXECUTE JAVA 'className')
+ */
+createTriggerBody
+    : (IF NOT EXISTS)? identifier
+      triggerTiming triggerEvent
+      ON TYPE? identifier
+      triggerAction
+    ;
+
+triggerTiming
+    : BEFORE
+    | AFTER
+    ;
+
+triggerEvent
+    : CREATE
+    | READ
+    | UPDATE
+    | DELETE
+    ;
+
+triggerAction
+    : EXECUTE identifier STRING_LITERAL
+    ;
+
+/**
+ * DROP TRIGGER statement
+ * Syntax: DROP TRIGGER [IF EXISTS] name
+ */
+dropTriggerBody
+    : (IF EXISTS)? identifier
+    ;
+
 // ============================================================================
 // DDL STATEMENTS - TRUNCATE
 // ============================================================================

engine/src/main/java/com/arcadedb/function/polyglot/PolyglotFunctionLibraryDefinition.java

@@ -20,7 +20,7 @@
 import com.arcadedb.database.Database;
 import com.arcadedb.function.FunctionLibraryDefinition;
 import com.arcadedb.query.polyglot.GraalPolyglotEngine;
-import org.graalvm.polyglot.Engine;
+import com.arcadedb.query.polyglot.PolyglotEngineManager;
 
 import java.util.*;
 import java.util.concurrent.*;
@@ -42,7 +42,8 @@ protected PolyglotFunctionLibraryDefinition(final Database database, final Strin
     this.libraryName = libraryName;
     this.language = language;
     this.allowedPackages = allowedPackages;
-    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, Engine.create()).setLanguage(language).setAllowedPackages(allowedPackages).build();
+    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, PolyglotEngineManager.getInstance().getSharedEngine())
+        .setLanguage(language).setAllowedPackages(allowedPackages).build();
   }
 
   public PolyglotFunctionLibraryDefinition registerFunction(final T function) {
@@ -51,7 +52,8 @@ public PolyglotFunctionLibraryDefinition registerFunction(final T function) {
 
     // REGISTER ALL THE FUNCTIONS UNDER THE NEW ENGINE INSTANCE
     this.polyglotEngine.close();
-    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, Engine.create()).setLanguage(language).setAllowedPackages(allowedPackages).build();
+    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, PolyglotEngineManager.getInstance().getSharedEngine())
+        .setLanguage(language).setAllowedPackages(allowedPackages).build();
     for (final T f : functions.values())
       f.init(this);
 

engine/src/main/java/com/arcadedb/query/polyglot/GraalPolyglotEngine.java

@@ -49,7 +49,8 @@ public class GraalPolyglotEngine implements AutoCloseable {
 
   static {
     try {
-      supportedLanguages = Engine.create().getLanguages().keySet();
+      // Use the shared engine to discover supported languages
+      supportedLanguages = PolyglotEngineManager.getInstance().getSharedEngine().getLanguages().keySet();
     } catch (Throwable e) {
       LogManager.instance().log(GraalPolyglotEngine.class, Level.SEVERE, "GraalVM Polyglot Engine: no languages found");
       supportedLanguages = Collections.emptySet();

engine/src/main/java/com/arcadedb/query/polyglot/PolyglotEngineManager.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright © 2021-present Arcade Data Ltd (info@arcadedata.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * SPDX-FileCopyrightText: 2021-present Arcade Data Ltd (info@arcadedata.com)
+ * SPDX-License-Identifier: Apache-2.0
+ */
+package com.arcadedb.query.polyglot;
+
+import com.arcadedb.log.LogManager;
+import org.graalvm.polyglot.Engine;
+
+import java.util.logging.Level;
+
+/**
+ * Singleton manager for GraalVM Polyglot Engine instances.
+ * The Engine is a heavyweight object that should be shared across multiple Context instances
+ * for optimal performance. This manager provides a single shared Engine instance for the entire
+ * ArcadeDB process.
+ *
+ * @author Luca Garulli (l.garulli@arcadedata.com)
+ */
+public class PolyglotEngineManager {
+  private static final PolyglotEngineManager INSTANCE = new PolyglotEngineManager();
+  private volatile     Engine                sharedEngine;
+
+  private PolyglotEngineManager() {
+    // Private constructor for singleton
+  }
+
+  public static PolyglotEngineManager getInstance() {
+    return INSTANCE;
+  }
+
+  /**
+   * Returns the shared GraalVM Engine instance. Creates it on first access (lazy initialization).
+   * The Engine is thread-safe and can be used concurrently by multiple contexts.
+   *
+   * @return the shared Engine instance
+   */
+  public Engine getSharedEngine() {
+    if (sharedEngine == null) {
+      synchronized (this) {
+        if (sharedEngine == null) {
+          LogManager.instance()
+              .log(this, Level.FINE, "Creating shared GraalVM Polyglot Engine for ArcadeDB process");
+          sharedEngine = Engine.create();
+        }
+      }
+    }
+    return sharedEngine;
+  }
+
+  /**
+   * Closes the shared Engine. This should only be called during application shutdown.
+   * After calling this method, subsequent calls to getSharedEngine() will create a new Engine.
+   */
+  public synchronized void closeSharedEngine() {
+    if (sharedEngine != null) {
+      try {
+        LogManager.instance().log(this, Level.FINE, "Closing shared GraalVM Polyglot Engine");
+        sharedEngine.close();
+      } catch (final Exception e) {
+        LogManager.instance().log(this, Level.WARNING, "Error closing shared GraalVM Polyglot Engine", e);
+      } finally {
+        sharedEngine = null;
+      }
+    }
+  }
+}

engine/src/main/java/com/arcadedb/query/polyglot/PolyglotQueryEngine.java

@@ -29,7 +29,6 @@
 import com.arcadedb.query.sql.executor.InternalResultSet;
 import com.arcadedb.query.sql.executor.ResultInternal;
 import com.arcadedb.query.sql.executor.ResultSet;
-import org.graalvm.polyglot.Engine;
 import org.graalvm.polyglot.Value;
 
 import java.util.*;
@@ -88,8 +87,8 @@ protected PolyglotQueryEngine(final DatabaseInternal database, final String lang
     this.language = language;
     this.database = database;
     this.allowedPackages = allowedPackages;
-    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, Engine.create()).setLanguage(language)
-        .setAllowedPackages(allowedPackages).build();
+    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, PolyglotEngineManager.getInstance().getSharedEngine())
+        .setLanguage(language).setAllowedPackages(allowedPackages).build();
     this.userCodeExecutorQueue = new ArrayBlockingQueue<>(10000);
     this.userCodeExecutor = new ThreadPoolExecutor(8, 8, 30, TimeUnit.SECONDS, userCodeExecutorQueue,
         new ThreadPoolExecutor.CallerRunsPolicy());
@@ -174,8 +173,8 @@ public QueryEngine registerFunctions(final String function) {
 
   @Override
   public QueryEngine unregisterFunctions() {
-    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, Engine.create()).setLanguage(language)
-        .setAllowedPackages(allowedPackages).build();
+    this.polyglotEngine = GraalPolyglotEngine.newBuilder(database, PolyglotEngineManager.getInstance().getSharedEngine())
+        .setLanguage(language).setAllowedPackages(allowedPackages).build();
     return this;
   }
 

engine/src/main/java/com/arcadedb/query/sql/antlr/SQLASTBuilder.java

@@ -5595,6 +5595,90 @@ public DropBucketStatement visitDropBucketStmt(final SQLParser.DropBucketStmtCon
     return stmt;
   }
 
+  // TRIGGER MANAGEMENT
+
+  /**
+   * Visit CREATE TRIGGER statement.
+   */
+  @Override
+  public CreateTriggerStatement visitCreateTriggerStmt(final SQLParser.CreateTriggerStmtContext ctx) {
+    final CreateTriggerStatement stmt = new CreateTriggerStatement(-1);
+    final SQLParser.CreateTriggerBodyContext bodyCtx = ctx.createTriggerBody();
+
+    // IF NOT EXISTS flag
+    stmt.ifNotExists = bodyCtx.IF() != null && bodyCtx.NOT() != null && bodyCtx.EXISTS() != null;
+
+    // Trigger name (first identifier)
+    stmt.name = (Identifier) visit(bodyCtx.identifier(0));
+
+    // Trigger timing (BEFORE or AFTER)
+    stmt.timing = (Identifier) visit(bodyCtx.triggerTiming());
+
+    // Trigger event (CREATE, READ, UPDATE, DELETE)
+    stmt.event = (Identifier) visit(bodyCtx.triggerEvent());
+
+    // Type name (second identifier - the one after ON)
+    stmt.typeName = (Identifier) visit(bodyCtx.identifier(1));
+
+    // Action type and code (SQL or JAVASCRIPT)
+    final SQLParser.TriggerActionContext actionCtx = bodyCtx.triggerAction();
+    final Identifier actionTypeId = (Identifier) visit(actionCtx.identifier());
+    stmt.actionType = actionTypeId;
+
+    // Extract string literal and remove quotes
+    final String rawText = actionCtx.STRING_LITERAL().getText();
+    stmt.actionCode = rawText.substring(1, rawText.length() - 1);
+
+    return stmt;
+  }
+
+  /**
+   * Visit DROP TRIGGER statement.
+   */
+  @Override
+  public DropTriggerStatement visitDropTriggerStmt(final SQLParser.DropTriggerStmtContext ctx) {
+    final DropTriggerStatement stmt = new DropTriggerStatement(-1);
+    final SQLParser.DropTriggerBodyContext bodyCtx = ctx.dropTriggerBody();
+
+    // Trigger name
+    stmt.name = (Identifier) visit(bodyCtx.identifier());
+
+    // IF EXISTS
+    stmt.ifExists = bodyCtx.IF() != null && bodyCtx.EXISTS() != null;
+
+    return stmt;
+  }
+
+  /**
+   * Visit trigger timing (BEFORE or AFTER).
+   */
+  @Override
+  public Identifier visitTriggerTiming(final SQLParser.TriggerTimingContext ctx) {
+    if (ctx.BEFORE() != null) {
+      return new Identifier("BEFORE");
+    } else if (ctx.AFTER() != null) {
+      return new Identifier("AFTER");
+    }
+    return null;
+  }
+
+  /**
+   * Visit trigger event (CREATE, READ, UPDATE, DELETE).
+   */
+  @Override
+  public Identifier visitTriggerEvent(final SQLParser.TriggerEventContext ctx) {
+    if (ctx.CREATE() != null) {
+      return new Identifier("CREATE");
+    } else if (ctx.READ() != null) {
+      return new Identifier("READ");
+    } else if (ctx.UPDATE() != null) {
+      return new Identifier("UPDATE");
+    } else if (ctx.DELETE() != null) {
+      return new Identifier("DELETE");
+    }
+    return null;
+  }
+
   // DDL STATEMENTS - TRUNCATE
 
   /**