feat: first definition of create class if not exists method

client/src/main/java/com/orientechnologies/orient/client/remote/metadata/schema/OSchemaRemote.java

@@ -15,6 +15,7 @@
 import com.orientechnologies.orient.core.metadata.security.ORole;
 import com.orientechnologies.orient.core.metadata.security.ORule;
 import com.orientechnologies.orient.core.record.impl.ODocument;
+import com.orientechnologies.orient.core.sql.executor.OResultSet;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Iterator;
@@ -219,6 +220,56 @@ public OClass createClass(
     return result;
   }
 
+  @Override
+  public boolean createClassIfNotExists(ODatabaseDocumentInternal database, String className) {
+    return createClassIfNotExists(database, className, new OClass[] {});
+  }
+
+  @Override
+  public boolean createClassIfNotExists(
+      ODatabaseDocumentInternal database, String className, OClass... superClasses) {
+    final Character wrongCharacter = OSchemaShared.checkClassNameIfValid(className);
+    if (wrongCharacter != null)
+      throw new OSchemaException(
+          "Invalid class name found. Character '"
+              + wrongCharacter
+              + "' cannot be used in class name '"
+              + className
+              + "'");
+
+    database.checkSecurity(ORule.ResourceGeneric.SCHEMA, ORole.PERMISSION_CREATE);
+    acquireSchemaWriteLock(database);
+    try {
+      StringBuilder cmd = new StringBuilder("create class ");
+      cmd.append('`');
+      cmd.append(className);
+      cmd.append('`');
+
+      List<OClass> superClassesList = new ArrayList<OClass>();
+      if (superClasses != null && superClasses.length > 0) {
+        boolean first = true;
+        for (OClass superClass : superClasses) {
+          // Filtering for null
+          if (superClass != null) {
+            if (first) cmd.append(" extends ");
+            else cmd.append(", ");
+            cmd.append(superClass.getName());
+            first = false;
+            superClassesList.add(superClass);
+          }
+        }
+      }
+
+      OResultSet queryResult = database.command(cmd.toString());
+      boolean created = queryResult.hasNext();
+      queryResult.close();
+      reload(database);
+      return created;
+    } finally {
+      releaseSchemaWriteLock(database);
+    }
+  }
+
   public OView createView(
       ODatabaseDocumentInternal database, OViewConfig cfg, ViewCreationListener listener)
       throws UnsupportedOperationException {

core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OImmutableSchema.java

@@ -147,6 +147,16 @@ public OClass createClass(String className, int[] clusterIds, OClass... superCla
     throw new UnsupportedOperationException();
   }
 
+  @Override
+  public boolean createClassIfNotExists(String className) {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public boolean createClassIfNotExists(String iClassName, OClass... superClasses) {
+    throw new UnsupportedOperationException();
+  }
+
   @Override
   public OClass createAbstractClass(String iClassName) {
     throw new UnsupportedOperationException();

core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OSchema.java

@@ -46,6 +46,10 @@ public interface OSchema {
 
   OClass createClass(String className, int[] clusterIds, OClass... superClasses);
 
+  boolean createClassIfNotExists(String className);
+
+  boolean createClassIfNotExists(String iClassName, OClass... superClasses);
+
   OClass createAbstractClass(String iClassName);
 
   OClass createAbstractClass(String iClassName, OClass iSuperClass);

core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OSchemaEmbedded.java

@@ -82,6 +82,36 @@ public OClass createClass(
     return doCreateClass(database, className, clusters, superClasses);
   }
 
+  @Override
+  public boolean createClassIfNotExists(ODatabaseDocumentInternal session, String className) {
+    try {
+      acquireSchemaWriteLock(session);
+      if (existsClass(className)) {
+        return false;
+      } else {
+        createClass(session, className);
+        return true;
+      }
+    } finally {
+      releaseSchemaWriteLock(session);
+    }
+  }
+
+  public boolean createClassIfNotExists(
+      ODatabaseDocumentInternal session, String className, OClass... superclasses) {
+    try {
+      acquireSchemaWriteLock(session);
+      if (existsClass(className)) {
+        return false;
+      } else {
+        createClass(session, className, superclasses);
+        return true;
+      }
+    } finally {
+      releaseSchemaWriteLock(session);
+    }
+  }
+
   private OClass doCreateClass(
       ODatabaseDocumentInternal database,
       final String className,

core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OSchemaProxy.java

@@ -215,6 +215,16 @@ public OClass createClass(String className, int clusters, OClass... superClasses
     return delegate.createClass(database, className, clusters, superClasses);
   }
 
+  @Override
+  public boolean createClassIfNotExists(String className) {
+    return delegate.createClassIfNotExists(database, className);
+  }
+
+  @Override
+  public boolean createClassIfNotExists(String className, OClass... superClasses) {
+    return delegate.createClassIfNotExists(database, className, superClasses);
+  }
+
   @Override
   public OClass getClassByClusterId(int clusterId) {
     return delegate.getClassByClusterId(clusterId);

core/src/main/java/com/orientechnologies/orient/core/metadata/schema/OSchemaShared.java

@@ -271,6 +271,12 @@ public abstract OView createView(
       String statement,
       Map<String, Object> metadata);
 
+  public abstract boolean createClassIfNotExists(
+      ODatabaseDocumentInternal session, String className);
+
+  public abstract boolean createClassIfNotExists(
+      ODatabaseDocumentInternal session, String className, OClass... superclasses);
+
   public abstract OView createView(ODatabaseDocumentInternal database, OViewConfig cfg);
 
   public abstract OView createView(

core/src/test/java/com/orientechnologies/orient/core/metadata/schema/CreateClassTest.java

@@ -0,0 +1,65 @@
+package com.orientechnologies.orient.core.metadata.schema;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertTrue;
+
+import com.orientechnologies.BaseMemoryDatabase;
+import org.junit.Test;
+
+public class CreateClassTest extends BaseMemoryDatabase {
+
+  @Test
+  public void testCreateClassSQL() {
+    db.command("drop class V").close();
+    db.command("create class V clusters 16").close();
+    db.command("create class X extends V clusters 32").close();
+
+    final OClass clazzV = db.getMetadata().getSchema().getClass("V");
+    assertEquals(16, clazzV.getClusterIds().length);
+
+    final OClass clazzX = db.getMetadata().getSchema().getClass("X");
+    assertEquals(32, clazzX.getClusterIds().length);
+  }
+
+  @Test
+  public void testCreateClassSQLSpecifiedClusters() {
+    int s = db.addCluster("second");
+    int t = db.addCluster("third");
+    db.command("drop class V").close();
+    db.command("create class V cluster " + s + "," + t).close();
+
+    final OClass clazzV = db.getMetadata().getSchema().getClass("V");
+    assertEquals(2, clazzV.getClusterIds().length);
+
+    assertEquals(s, clazzV.getClusterIds()[0]);
+    assertEquals(t, clazzV.getClusterIds()[1]);
+  }
+
+  @Test
+  public void testCreateClassIfNotExists() {
+    OSchema schema = db.getMetadata().getSchema();
+    schema.createClass("TestCreateClass");
+    boolean result = schema.createClassIfNotExists("TestCreateClassNotExists");
+    assertTrue(result);
+    assertNotNull(schema.getClass("TestCreateClassNotExists"));
+
+    result = schema.createClassIfNotExists("TestCreateClass");
+    assertFalse(result);
+  }
+
+  @Test
+  public void testCreateClassIfNotExistsSuperclass() {
+    OSchema schema = db.getMetadata().getSchema();
+    schema.createClass("TestCreateClass");
+    boolean result =
+        schema.createClassIfNotExists("TestCreateClassNotExists", schema.getClass("V"));
+    assertTrue(result);
+    assertNotNull(schema.getClass("TestCreateClassNotExists"));
+    assertEquals(1, schema.getClass("TestCreateClassNotExists").getSuperClasses().size());
+
+    result = schema.createClassIfNotExists("TestCreateClass");
+    assertFalse(result);
+  }
+}

object/src/main/java/com/orientechnologies/orient/object/metadata/schema/OSchemaProxyObject.java

@@ -236,6 +236,16 @@ public OClass createClass(String className, int clusters, OClass... superClasses
     return underlying.createClass(className, clusters, superClasses);
   }
 
+  @Override
+  public boolean createClassIfNotExists(String className) {
+    return underlying.createClassIfNotExists(className);
+  }
+
+  @Override
+  public boolean createClassIfNotExists(String className, OClass... superClasses) {
+    return underlying.createClassIfNotExists(className, superClasses);
+  }
+
   public OSchema getUnderlying() {
     return underlying;
   }