PostgreSQLSequenceHandler.java

/*
** Module   : PostgreSQLSequenceHandler.java
** Abstract : Static class that handles sequence functions and statements from Progress / OpenEdge 10.x.
**
** Copyright (c) 2012-2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------Description---------------------------------
** 001 OM  20121116 Created initial version with CURRVAL, NEXTVAL and SETVAL support only.
** 002 SVL 20130331 Upgraded to Hibernate 4.
** 003 OM  20130712 Fixed extraction data from ResultSets. Added error handling.
** 004 OM  20151130 Rewrote the NEXT-VALUE sequence primitive to use one query for most cases and
**                  a second query for handling exceptions. Code maintenance. Added logging.
** 005 ECF 20160501 Replaced direct SQL use with a more efficient implementation.
** 006 ECF 20160609 SQL performance improvement.
** 007 HC  20161024 Removed an unused import causing compilation error in IDEs.
** 008 ECF 20180219 Reduce Hibernate session flushing, if possible.
** 009 OM  20200906 New ORM implementation.
**     OM  20220531 Fixed an error message.
**     CA  20221014 Keep a lowercase map of crtSeqList sequence keys, as the change in 
**                  SequenceManager.legacyMap will always load all sequences.
**     RAA 20230109 Changed inline statement(s) to prepared statement(s).
** 010 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 011 OM  20241128 Multi-tenant runtime support: selected the proper persistence context, eventually
**                  based on [sharedDb] parameter.
** 012 OM  20250110 Added sequence support for multi-tenant databases.
*/

/*
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** 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.
**
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** 
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package com.goldencode.p2j.persist.sequence;

import java.sql.*;
import java.util.*;
import java.util.logging.Level;

import com.goldencode.p2j.persist.*;
import com.goldencode.p2j.persist.dialect.*;
import com.goldencode.p2j.persist.orm.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;

/**
 * PostgreSQL implementation of sequences using a native SQL sequence primitives queries.
 * Each primitive tries to execute exactly one database query (with the exception of NEXT-VALUE, 
 * where the output is checked to match the P4GL jump-to INITIAL value instead of MIN-VALUE).
 */
public class PostgreSQLSequenceHandler
extends SequenceHandler
{
   /** J2SE Logger */
   private static final CentralLogger LOG = CentralLogger.get(PostgreSQLSequenceHandler.class);
   
   /** 
    * Error code when an attempt to pass the boundaries of a sequence. This is a generic warning
    * SQL state and cannot identify by itself the exact sequence status. 
    */
   private static final String OBJECT_NOT_IN_PREREQUISITE_STATE = "55000";
   
   /** The list of sequences grouped by databases. It uses lazy initialization. */
   private HashMap<String, LinkedList<String>> sequences = null;
   
   /**
    * The only constructor takes the name of the database as argument.
    * It is passed on to super class.
    *
    * @param   ldbName
    *          The database logical name on which this handler will work with.
    */
   public PostgreSQLSequenceHandler(String ldbName)
   {
      super(ldbName);
   }
   
   /**
    * Queries the current value of a sequence.
    * <p>
    * This method should be called only in a safe environment, where the database-level lock for
    * access to sequences has already been acquired.
    *
    * @param   seqName
    *          The name of the sequence.
    * @param   ldbName
    *          The database to which the sequence belongs to. It is assumed it is not null and valid.
    * @param   tenantId
    *          The tenant id. If present (not null) it is checked. If not it is computed as
    *          {@code tenant-id(ldbName}).
    *
    * @return  the current value of the sequence
    */
   @Override
   protected int64 safeGetCurrentValue(String seqName, String ldbName, Long tenantId)
   {
      Sequence seq = SequenceManager.getSequence(ldbName, seqName);
      if (seq == null)
      {
         ErrorManager.recordOrThrowError(2913, seqName.toUpperCase(), "");
         // Unknown sequence expression <sequence name>. (2913)
         return new int64();
      }
      
      // this will also create the instance if needed:
      Persistence persistence = ConnectionManager.getPersistence(ldbName);
      if (tenantId != null)
      {
         int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
         if (crtTenant != tenantId)
         {
            // NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
            ErrorManager.recordOrThrowError(15956);
            // Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
            return new int64();
         }
      }
      
      Dialect dialect = persistence.getDialect();
      String getCrtValQuery = dialect.getSequenceCurrValString(seqName);
      
      try
      {
         return getResultValue(persistence.getSingleSQLResult(getCrtValQuery, !seq.isMultiTenant(), null));
      }
      catch (PersistenceException pe)
      {
         if (LOG.isLoggable(Level.WARNING)) 
         {
            LOG.log(Level.WARNING, 
                    "Failed to get CURRENT-VALUE from " + ldbName + "." + seqName + ": " + pe.getMessage());
         }
      }
      
      // if here then some error occurred, return unknown value
      return new int64();
   }
   
   /**
    * Computes and returns the next value of a sequence.
    * <p>
    * This method should be called only in a safe environment, where the database-level lock for
    * access to sequences has already been acquired.
    *
    * @param   seqName
    *          The name of the sequence.
    * @param   ldbName
    *          The database to which the sequence belongs to. It is assumed it is not {@code null} and valid.
    * @param   tenantId
    *          The tenant id. If present (not null) it is checked. If not it is computed as
    *          {@code tenant-id(ldbName}).
    *
    * @return  the next value of the sequence or unknown value (?) if sequence/database not found
    *          or the sequence is not cycling and has passed the maximum/minimum value.
    */
   @Override
   protected int64 safeGetNextValue(String seqName, String ldbName, Long tenantId)
   {
      Sequence seq = SequenceManager.getSequence(ldbName, seqName);
      if (seq == null)
      {
         ErrorManager.recordOrThrowError(2913, seqName.toUpperCase(), "");
         // Unknown sequence expression <sequence name>. (2913)
         return new int64();
      }
      
      Persistence persistence = ConnectionManager.getPersistence(ldbName);
      if (tenantId != null)
      {
         int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
         if (crtTenant != tenantId)
         {
            // NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
            ErrorManager.recordOrThrowError(15956);
            // Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
            return new int64();
         }
      }
      
      Dialect dialect = persistence.getDialect();
      String getNextValQuery = dialect.getSequenceNextValString(seqName);
      
      try
      {
         int64 resultValue = getResultValue(
               persistence.getSingleSQLResult(getNextValQuery, !seq.isMultiTenant(), null));
         
         // PostgreSQL is different from Progress when cycling:
         //    it will make the counter jump from MAX_VALUE to MIN_VALUE (and the reverse) 
         //    instead, 4GL will jump back to INITIAL_VALUE
         if (seq.isCycle())
         {
            // in a cycling sequence resultValue is never null/unknown
            long crtVal = resultValue.longValue();
            
            // did the cycle jump occurred?
            if (seq.getIncrement() > 0 && crtVal == seq.getMin())
            {
               // if this is a nop, skip it
               long ret = seq.getInitial();
               if (crtVal != ret)
               {
                  safeSetValue(seqName, ldbName, ret, tenantId);
                  return new int64(ret);
               }
            }
         }
         
         return resultValue;
      }
      catch (PersistenceException pe)
      {
         // heuristically analyse the exception message to filter out expected errors
         boolean outOfBoundsException = false;
         if (pe.getCause() instanceof SQLException)
         {
            SQLException jdbcExc = (SQLException) pe.getCause();
            if (jdbcExc.getErrorCode() == 0 && 
                OBJECT_NOT_IN_PREREQUISITE_STATE.equals(jdbcExc.getSQLState()))
            {
               // String errMessage = psqlExc.getMessage();
               // if (errMessage.contains("reached maximum value") ||
               //     errMessage.contains("reached minimum value"))
               outOfBoundsException = true;
            }
         }
         if (!outOfBoundsException)
         {
            // some other nasty thing has happened, report it:
            if (LOG.isLoggable(Level.WARNING))
            {
               LOG.log(Level.WARNING,
                       "Failed to get NEXT-VALUE from " + ldbName + "." + seqName + ": " + pe.getMessage());
            }
         }
      }
      
      // if here then some error occurred, return unknown value
      return new int64();
   }
   
   /**
    * Initialize (reset) the current value of a sequence.
    * <p>
    * This method should be called only in a safe environment, where the database-level lock for
    * access to sequences has already been acquired.
    *
    * @param   seqName
    *          The name of the sequence.
    * @param   ldbName
    *          The database to which the sequence belongs to. 
    *          It is assumed it is not null and valid.
    * @param   newVal
    *          The value the sequence will be reset to.
    * @param   tenantId
    *          The tenant id. If present (not null) it is checked. If not it is computed as
    *          {@code tenant-id(ldbName}).
    */
   @Override
   protected void safeSetValue(String seqName, String ldbName, long newVal, Long tenantId)
   {
      Sequence seq = SequenceManager.getSequence(ldbName, seqName);
      if (seq == null)
      {
         // note: this is a bit too late, seqName is the SQL name, not legacy
         ErrorManager.recordOrThrowError(3133, seqName.toUpperCase(), ""); 
         // SYSTEM ERROR: Sequence <sequence name> not found. (3133)
         return;
      }
      if (seq.getMin() > newVal || newVal > seq.getMax())
      {
         ErrorManager.recordOrThrowError(3132,
               "Cannot set sequence " + seq.getLegacyName().toUpperCase() +
               " beyond its max/min values");
         return;
      }
      
      Persistence persistence = ConnectionManager.getPersistence(ldbName);
      if (tenantId != null)
      {
         int crtTenant = persistence.getContext(Persistence.PRIVATE_CTX).getTenantId();
         if (crtTenant != tenantId)
         {
            // NOTE: super-tenants are not implemented yet so we raise this unconditionally, for the moment:
            ErrorManager.recordOrThrowError(15956);
            // Only super-tenants may use a tenant-id other than their own in a sequence function. (15956)
            return;
         }
      }
      
      Dialect dialect = persistence.getDialect();
      Object[] args = new Object[] {seqName, newVal};
      String setCrtValQuery = dialect.getSequenceSetValString();
      
      try
      {
         persistence.getSingleSQLResult(setCrtValQuery, !seq.isMultiTenant(), args);
      }
      catch (PersistenceException pe)
      {
         if (LOG.isLoggable(Level.WARNING))
         {
            LOG.log(Level.WARNING,
                    "Failed to set CURRENT-VALUE to " + ldbName + "." + seqName + ": " +
                    pe.getMessage());
         }
      }
   }
   
   /**
    * Test whether the database contains a sequence. This is useful to identify the correct
    * database/sequences when a 4GL static function / statement is called without the database
    * parameter.
    * <p>
    * This method should be called only in a safe environment, where the database-level lock for
    * access to sequences has already been acquired.
    *
    * @param   seqName
    *          The name of the sequence.
    * @param   ldbName
    *          The database to which the sequence belongs to. If is null then the first connected
    *          database is assumed.
    *
    * @return  <code>true</code> if the sequence is defined in the database
    */
   @Override
   protected boolean safeContains(String seqName, String ldbName)
   {
      // lazy initialization
      if (sequences == null)
      {
         sequences = new HashMap<>();
      }
      
      // make sure the structure is initialized for this database:
      LinkedList<String> crtSeqList;
      if (!sequences.containsKey(ldbName))
      {
         // create the list 
         crtSeqList = new LinkedList<>();
         sequences.put(ldbName, crtSeqList);
         
         Persistence persistence = ConnectionManager.getPersistence(ldbName);
         try
         {
            ScrollableResults<String> rs = persistence.executeSQLQuery(
                  "SELECT relname " +
                  "FROM \"pg_class\" " + // TODO: this needs ADMIN rights !
                  "WHERE relkind='S';",
                  Persistence.META_CTX,
                  null);
            while (rs.next())
            {
               crtSeqList.add(rs.get(0, String.class).toLowerCase());
            }
         }
         catch (PersistenceException pe)
         {
            if (LOG.isLoggable(Level.WARNING))
            {
               LOG.log(Level.WARNING,
                       "Failed to get sequence list from " + ldbName + ": " + pe.getMessage());
            }
            return false;
         }
      }
      else
      {
         crtSeqList = sequences.get(ldbName);
      }
      
      // now check whether the sequence is in database
      return crtSeqList.contains(seqName.toLowerCase());
   }
}