TempTableResultSet.java

/*
** Module   : TempTableResultSet.java
** Abstract : A result set used to serialize temp table data and send it to a remote side. 
**
** Copyright (c) 2013-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 CA  20130610 Created initial version.
** 002 CA  20140110 Protected against NPEs, when used from Java side (for a OUTPUT parameter).
** 003 CA  20140124 Added NPE protection.
** 004 CA  20140214 Do not read _multiplex column; use the actual type instead of Hibernate type
**                  names when creating a new PropertyDefinition.
** 005 CA  20140626 Fixed usage from Java code: the default c'tor must not be used, always use
**                  the TempTableResultSet(boolean) c'tor with the argument set to false, as 
**                  from Java code instances of this class can be used only in OUTPUT mode.
** 006 SVL 20140709 Legacy property names are passed in the result set.
** 007 OM  20140801 Initialize iterators after setting the rows from appserver call.
** 008 CA  20140812 Added warnings to APIs which should not be used outside of P2J internal code.
** 009 EVL 20160223 Javadoc fixes to make compatible with Oracle Java 8 for Solaris 10.
** 010 ECF 20160225 Changes required by new PropertyHelper implementation.
** 011 ECF 20190823 Temporary workaround for regression caused by new variables in temp-table
**                  DMOs. TODO: proper fix needed, as this workaround breaks dataset support.
** 012 CA  20190812 Added another c'tor, which allows remote side arguments.
**     CA  20190826 Ensure the legacy table properties are returned in the correct legacy order.
** 013 CA  20191119 Added support for before-table.
** 014 CA  20200427 Flush the buffer before reading the records.
** 015 ECF 20200906 New ORM implementation.
** 016 OM  20201001 Improved DMO manipulation performance by caching slow Property annotation access.
**     SVL 20201030 Reflect extension of PropertyDefinition.
** 017 SVL 20210614 Added copyRows parameter.
**     SVL 20210701 Added clearRows.
**     CA  20221006 Do not access tableHandle() in the FWD runtime, get the TempTable instance directly.
**                  Refs #6826
**     OM  20221220 Simlpified TempTableBuilder.getOrderedPropertyNames() signature/implementation.
**     IAS 20221029 Re-worked 'init' method.
**     SVL 20230113 Improved performance by replacing some "for-each" loops with indexed "for" loops.
*/

/*
** 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 may find a copy of the GNU Affero GPL version 3 at the following
** location: https://www.gnu.org/licenses/agpl-3.0.en.html
** 
** Additional terms under GNU Affero GPL version 3 section 7:
** 
**   Under Section 7 of the GNU Affero GPL version 3, the following additional
**   terms apply to the works covered under the License.  These additional terms
**   are non-permissive additional terms allowed under Section 7 of the GNU
**   Affero GPL version 3 and may not be removed by you.
** 
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*/

package com.goldencode.p2j.persist;

import com.goldencode.p2j.persist.orm.*;
import java.sql.*;
import java.util.*;

/**
 * Implements a method of serializing the metadata and the full data of a temp-table, specified
 * by a {@link Temporary temp-table DMO}.  The data is read fully in memory and sent to the remote
 * side row by row; the DMO metadata is used to extract the properties and their settings (type
 * and extent).  Note that each send row will have the values in the same order as the DMO's
 * properties.
 * <p>
 * The {@link #TempTableResultSet(Temporary, boolean, boolean, boolean)} must not be used outside
 * of the P2J runtime, as it is dependent on the P2J's persistence frame to read the DMO's data.
 * <p>
 * From Java code, use the {@link #TempTableResultSet()} to instantiate a new, empty, result set;
 * this will be used as a container to transport back the result and the metadat.
 */
public class TempTableResultSet
extends TableResultSet
{
   /**
    * The DMO associated with the temp table; this will be used to extract the DMO metadata and 
    * the table data.
    */
   private Temporary dmo;
   
   /** Iterator over the DMO's properties. */
   private Iterator<PropertyDefinition> propIter;
   
   /** Iterator over the temp-table's data. */
   private Iterator<Object[]> rowIter;
   
   /** Iterator over the temp-table rows' meta information. */
   private Iterator<Object[]> rowMetaIter;
   
   /**
    * Default c'tor, explicitly added to allow instances of this class to be created on 
    * deserialization. Not for public use.
    */
   public TempTableResultSet()
   {
   }
   
   /**
    * Create a new instance of this result set, when it acts as a container for an 
    * OUTPUT parameter received from the remote side.
    * 
    * @param    output
    *           Flag indicating this table is sent in OUTPUT mode.  Must always be set to
    *           <code>true</code>.
    * 
    * @throws   IllegalStateException
    *           If the <code>output</code> parameter is not set to <code>true</code>.
    */
   public TempTableResultSet(boolean output)
   {
      super(false, output, false);
      
      if (!output)
      {
         throw new IllegalStateException("This c'tor must be used only in OUTPUT mode!");
      }
   }
   
   /**
    * Create a new instance of this result set, when it acts as a container for an 
    * OUTPUT parameter received from the remote side.
    * 
    * @param    output
    *           Flag indicating this table is sent in OUTPUT mode.  Must always be set to
    *           <code>true</code>.
    * @param    append
    *           Flag indicating this table is sent in APPEND mode.
    * 
    * @throws   IllegalStateException
    *           If the <code>output</code> parameter is not set to <code>true</code>.
    */
   public TempTableResultSet(boolean output, boolean append)
   {
      super(false, output, append);
      
      if (!output)
      {
         throw new IllegalStateException("This c'tor must be used only in OUTPUT mode!");
      }
   }

   /**
    * Create a new instance of this result set and associate it with the metadata and data for
    * the specified temp DMO.
    * 
    * @param    dmo
    *           DMO instance returned by a previous call to {@link TemporaryBuffer#define} on the 
    *           source temporary buffer.
    * @param    input
    *           Flag indicating this table is sent in INPUT or INPUT-OUTPUT mode.
    * @param    output
    *           Flag indicating this table is sent in OUTPUT or INPUT-OUTPUT mode.
    * @param    append
    *           Flag indicating this table is sent in APPEND mode.
    *           
    */
   public TempTableResultSet(Temporary dmo, boolean input, boolean output, boolean append)
   {
      this(dmo, input, output, append, true);
   }

   /**
    * Create a new instance of this result set and associate it with the metadata and data for
    * the specified temp DMO.
    *
    * @param    dmo
    *           DMO instance returned by a previous call to {@link TemporaryBuffer#define} on the
    *           source temporary buffer.
    * @param    input
    *           Flag indicating this table is sent in INPUT or INPUT-OUTPUT mode.
    * @param    output
    *           Flag indicating this table is sent in OUTPUT or INPUT-OUTPUT mode.
    * @param    append
    *           Flag indicating this table is sent in APPEND mode.
    * @param   copyRows
    *          <code>true</code>> to transfer rows in INPUT direction. <code>false</code>> to transfer only
    *          table definitions.
    */
   public TempTableResultSet(Temporary dmo, boolean input, boolean output, boolean append, boolean copyRows)
   {
      super(input, output, append);
      this.dmo = dmo;
      if (dmo != null)
      {
         init(copyRows);
      }
   }
   
   /**
    * Set the data sent by a remote side, after the remote appserver call.
    *
    * @param    rows
    *           The data sent by the remote side.
    */
   @Override
   public void setRows(java.util.List<Object[]> rows)
   {
      super.setRows(rows);
      
      rowIter = rows.iterator();
   }
   
   /**
    * Set the meta row information sent by a remote side, after the remote appserver call.
    * 
    * @param    rowsMeta
    *           The meta information sent by the remote side.
    */
   @Override
   public void setRowsMeta(java.util.List<Object[]> rowsMeta)
   {
      super.setRowsMeta(rowsMeta);
      
      rowMetaIter = rowsMeta.iterator();
   }
   
   /**
    * Set the metadata sent by a remote side, after the remote appserver call.
    * 
    * @param    properties
    *           The metadata sent by the remote side.
    */
   @Override
   public void setProperties(java.util.List<PropertyDefinition> properties)
   {
      super.setProperties(properties);
      
      propIter = properties.iterator();
   }
   
   /**
    * Check if there are more properties for this DMO.
    * <p>
    * WARNING: this allows only one iteration over the properties and is for internal usage
    * only.  Use {@link #asResultSet()} and the associated {@link ResultSetMetaData} instead.
    * 
    * @return   See above.
    */
   public boolean hasMoreProperties()
   {
      return (propIter == null) ? false : propIter.hasNext();
   }
   
   /**
    * Returns the next property of this DMO.
    * <p>
    * WARNING: this allows only one iteration over the properties and is for internal usage
    * only.  Use {@link #asResultSet()} and the associated {@link ResultSetMetaData} instead.
    * 
    * @return   See above.
    */
   public PropertyDefinition nextProperty()
   {
      return propIter.next();
   }
   
   /**
    * Check if there are more rows for this table.
    * <p>
    * WARNING: this allows only one iteration over the properties and is for internal usage
    * only.  Use {@link #asResultSet()} instead.
    * 
    * @return   See above.
    */
   public boolean hasMoreRows()
   {
      return (rowIter == null) ? false : rowIter.hasNext();
   }
   
   /**
    * Returns the data for the next row.
    * <p>
    * WARNING: this allows only one iteration over the properties and is for internal usage
    * only.  Use {@link #asResultSet()} instead.
    * 
    * @return    See above.
    */
   public Object[] nextRow()
   {
      return rowIter.next();
   }
   
   /**
    * Used in conjunction with {@link #hasMoreRows()}, it provides a mechanism for  subclasses to
    * send the row meta information in an iterator-like form.
    * <p>
    * Override this method so that when {@link #hasMoreRows} returns <code>true</code>, this will
    * return the next row in the table.
    * <p>
    * WARNING: this allows only one iteration over the properties and is for internal usage
    * only.  Use {@link #asResultSet()} and instead.
    * 
    * @return   Default it returns <code>null</code>.
    */
   @Override
   public Object[] nextRowMeta()
   {
      return rowMetaIter.next();
   }

   /**
    * Delete row data.
    */
   @Override
   public void clearRows()
   {
      super.clearRows();
      rowIter = null;
      rowMetaIter = null;
   }
   
   /**
    * Initialize this result set, by reading the entire temp-table in memory.
    *
    * @param    copyRows
    *           <code>true</code>> to transfer rows in INPUT direction. <code>false</code>> to transfer only
    *           table definitions.
    * 
    * TODO: improve this (i.e. use an open cursor or some other alternative to not read the data
    *       in memory)
    * 
    */
   private void init(boolean copyRows)
   {
      TemporaryBuffer buffer = (TemporaryBuffer) ((BufferReference) dmo).buffer();
      
      // this is executed on the top-level block finish, before the buffer scope finalizables.
      // so we need to flush here, to ensure all records are in the database.
      try
      {
         buffer.flush();
      }
      catch (ValidationException e1)
      {
         // TODO: can this happen?
      }
      
      Class<? extends DataModelObject> srcIface = buffer.getDMOInterface();
      TempTable tt = buffer.getParentTable();
      DmoMeta dmoInfo = DmoMetadataManager.getDmoInfo(srcIface);
      
      String[] dmoProps = TempTableBuilder.getOrderedPropertyNames(tt);
      Map<String, Integer> dmoPropIndex = new HashMap<>();
      for (int i = 0; i < dmoProps.length; i++)
      {
         dmoPropIndex.put(dmoProps[i], i);
      }
      
      Iterator<Property> iter = dmoInfo.getFields(false); // skip properties that are not accessible via the DMO's API.
      Map<Integer, PropertyDefinition> mprops = new TreeMap<>();
      iter.forEachRemaining(prop -> mprops.put(dmoPropIndex.get(prop.name), new PropertyDefinition(prop)));
      ArrayList<PropertyDefinition> lprops = new ArrayList<>(mprops.values());

      if (copyRows)
      {
         java.util.List<Object[][]> rowData = TemporaryBuffer.readAllRows(dmo, lprops);

         java.util.List<Object[]> rows = new ArrayList<>(rowData.size());
         java.util.List<Object[]> rowsMeta = new ArrayList<>(rowData.size());
         rowData.forEach(rd -> {
            rows.add(rd[0]);
            rowsMeta.add(rd[1]);
         });

         rowIter = rows.iterator();
         rowMetaIter = rowsMeta.iterator();
      }

      propIter = lprops.iterator();
   }
}