add TxnIdGenerator

modules/dbsupport/src/main/java/org/jpos/ee/TxnIdGenerator.java

@@ -0,0 +1,61 @@
+/*
+ * jPOS Project [http://jpos.org]
+ * Copyright (C) 2000-2024 jPOS Software SRL
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package org.jpos.ee;
+
+import org.hibernate.engine.spi.SharedSessionContractImplementor;
+import org.hibernate.id.IdentifierGenerator;
+import org.jpos.q2.Q2;
+import org.jpos.transaction.TxnId;
+
+import java.io.Serializable;
+import java.lang.reflect.Field;
+import java.time.Instant;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+
+@SuppressWarnings("unused")
+public class TxnIdGenerator implements IdentifierGenerator {
+    private static final int nodeId;
+    private static final ConcurrentMap<Class<?>, Class<?>> idFieldTypeCache = new ConcurrentHashMap<>();
+
+    static {
+        nodeId = Q2.getQ2().node();
+    }
+    @Override
+    public Serializable generate(SharedSessionContractImplementor session, Object object) {
+        Class<?> entityClass = object.getClass();
+        Class<?> idType = idFieldTypeCache.computeIfAbsent(entityClass, cls -> {
+            try {
+                Field idField = cls.getDeclaredField("id");
+                idField.setAccessible(true); 
+                return idField.getType();
+            } catch (NoSuchFieldException e) {
+                throw new RuntimeException("Failed to determine ID field type for entity: " + cls.getName(), e);
+            }
+        });
+        TxnId txnId = TxnId.create(Instant.now(), nodeId, System.nanoTime());
+        if (idType.equals(String.class)) {
+            return txnId.toString();
+        } else if (idType.equals(Long.class)) {
+            return txnId.id();
+        } else {
+            throw new UnsupportedOperationException("Unsupported ID type: " + idType);
+        }
+    }
+}