public class TriggerAssignedIdentityGenerator extends AbstractPostInsertGenerator {

    public InsertGeneratedIdentifierDelegate getInsertGeneratedIdentifierDelegate(
            final PostInsertIdentityPersister persister, final Dialect dialect,
            final boolean isGetGeneratedKeysEnabled)
    throws HibernateException {
        return new Delegate(persister, dialect);
    }

    public static class Delegate extends AbstractReturningDelegate {
        private final Dialect dialect;

        private final String[] keyColumns;

        public Delegate(final PostInsertIdentityPersister persister,
                        final Dialect dialect) {
            super(persister);
            this.dialect = dialect;
            this.keyColumns = getPersister().getRootTableKeyColumnNames();
            if (keyColumns.length > 1) {
                throw new HibernateException(
                        "trigger assigned identity generator cannot be used with multi-column keys");
            }
        }

        public IdentifierGeneratingInsert prepareIdentifierGeneratingInsert() {
            return new NoCommentsInsert(dialect);
        }

        protected PreparedStatement prepare(final String insertSQL,
                final SessionImplementor session) throws SQLException {
            return session.getBatcher().prepareStatement(insertSQL, keyColumns);
        }

        protected Serializable executeAndExtract(final PreparedStatement insert)
            throws SQLException {
            insert.executeUpdate();
            return IdentifierGeneratorFactory.getGeneratedIdentity(insert.getGeneratedKeys(), getPersister()
                    .getIdentifierType());
        }
    }

import org.hibernate.HibernateException;
import org.hibernate.dialect.Dialect;
import org.hibernate.engine.SessionImplementor;
import org.hibernate.id.AbstractPostInsertGenerator;
import org.hibernate.id.IdentifierGeneratorHelper;
import org.hibernate.id.PostInsertIdentityPersister;
import org.hibernate.id.SequenceIdentityGenerator.NoCommentsInsert;
import org.hibernate.id.insert.AbstractReturningDelegate;
import org.hibernate.id.insert.IdentifierGeneratingInsert;
import org.hibernate.id.insert.InsertGeneratedIdentifierDelegate;

import java.io.Serializable;
import java.sql.PreparedStatement;
import java.sql.SQLException;


public class TriggerAssignedIdentityGenerator extends AbstractPostInsertGenerator {
  public InsertGeneratedIdentifierDelegate getInsertGeneratedIdentifierDelegate(PostInsertIdentityPersister persister, Dialect dialect, boolean isGetGeneratedKeysEnabled) throws HibernateException {
    return new Delegate(persister, dialect);
  }

  public static class Delegate extends AbstractReturningDelegate {
    private final Dialect dialect;

    private final String[] keyColumns;

    public Delegate(PostInsertIdentityPersister persister, Dialect dialect) {
      super(persister);
      this.dialect = dialect;
      this.keyColumns = getPersister().getRootTableKeyColumnNames();
      if (keyColumns.length > 1) {
        throw new HibernateException("trigger assigned identity generator cannot be used with multi-column keys");
      }
    }

    public IdentifierGeneratingInsert prepareIdentifierGeneratingInsert() {
      NoCommentsInsert insert = new NoCommentsInsert(dialect);
      return insert;
    }

    protected PreparedStatement prepare(String insertSQL, SessionImplementor session) throws SQLException {
      return session.getBatcher().prepareStatement(insertSQL, keyColumns);
    }

    protected Serializable executeAndExtract(PreparedStatement insert) throws SQLException {
      insert.executeUpdate();
      return IdentifierGeneratorHelper.getGeneratedIdentity(insert.getGeneratedKeys(), getPersister().getIdentifierType());
    }
  }
}