OrderedRowStructure.java
/*
** Module : OrderedRowStructure.java
** Abstract : Defines a row structure in a query. This time, the fields should be ordered
**
** Copyright (c) 2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ----------------------------------------Description---------------------------------------
** 001 AL2 20231128 Initial version.
** AL2 20231211 Recieve the DMO meta directly in the constructor. Refactored iterator creation.
** AL2 20231212 Use dmoMeta directly, without getter.
** AL2 20231212 Fixed method used to retrieve propetry index.
*/
/*
** 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:
**
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*/
package com.goldencode.p2j.persist.orm;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.*;
import com.goldencode.p2j.persist.*;
/**
* The fastest implementation of incomplete row structure. This presumes that the
* fields are hydrated in a convenient order (the same order they appear in the
* data array). This way, we can store a bitset to mark which fields exactly we
* are going to hydrate.
*/
public class OrderedRowStructure
extends AbstractRowStructure
{
/** The collected fields for select query */
private BitSet fields;
/** The last field (not recid or multiplex) that was appended. */
private int lastFieldSet = -1;
/** The number of SQL columns that are needed to do the hydration of this structure */
private int count = 0;
/** The recid property, if any appended */
private Property recidProp;
/** The multiplex property, if any appended */
private Property multiplexProp;
/**
* Create a new instance.
*
* @param dmoMeta
* The DMO metadata of the underlying DMO for this structure.
*/
public OrderedRowStructure(DmoMeta dmoMeta)
{
super(dmoMeta);
}
/**
* Append the recid to the row structure.
*
* @param recid
* The recid property to be appended to the structure.
*
* @return {@code true} if adding the recid to the row structure succeeded
* If there is some invariant on the structure, adding props may fail.
*/
@Override
public boolean addRecid(Property recid)
{
if (this.lastFieldSet >= 0 || this.multiplexProp != null || recidProp != null)
{
// if we already added the multiplex or a field, adding the recid is too late
// this will also fail if we add the recid more than once
return false;
}
this.recidProp = recid;
this.count++;
return true;
}
/**
* Append the multiplex to the row structure.
*
* @param multiplex
* The multiplex property to be appended to the structure.
*
* @return {@code true} if adding the multiplex to the row structure succeeded
* If there is some invariant on the structure, adding props may fail.
*/
@Override
public boolean addMultiplex(Property multiplex)
{
if (this.lastFieldSet >= 0 || multiplexProp != null)
{
// if we didn't set the recid already or we added a field,
// adding the multiplex is too late or too early
// also, if we already added the multiplex, we invariant is violated
return false;
}
this.multiplexProp = multiplex;
this.count++;
return true;
}
/**
* Append a property to the row structure. This doesn't check if the property actually belongs to the
* DMO class used for this structure.
*
* @param prop
* The property to be appended to the structure.
*
* @return {@code true} if adding the prop to the row structure succeeded
* If there is some invariant on the structure, adding props may fail.
*/
@Override
public boolean addProperty(Property prop)
{
if (super.addProperty(prop))
{
return true;
}
int fieldId = dmoMeta.recordMeta.getIndexOfProperty(prop.name);
if (this.lastFieldSet >= fieldId)
{
// we are not setting the fields in order
return false;
}
if (fields == null)
{
this.fields = new BitSet();
}
fields.set(fieldId);
this.lastFieldSet = fieldId;
this.count += getPropertyMeta()[fieldId].columnCount;
return true;
}
/**
* Retrieve the number of SQL fields that will be interpreted by this row structure. This is not the
* same as the number of properties (e.g. datetime-tz consumes 2 SQL columns)
*
* @return The number of SQL fields that are covered by this row structure.
*/
@Override
public int getCount()
{
return this.count;
}
/**
* Retrieve an iterator to all properties in this structure, including the recid and multiplex.
*
* @return An iterator to all properties in this structure, in order of their append.
*/
@Override
public Iterator<Property> getProps()
{
return new Iterator<Property>()
{
private int phase = ReservedProperty.ID_PRIMARY_KEY;
@Override
public boolean hasNext()
{
if (phase == ReservedProperty.ID_PRIMARY_KEY)
{
if (recidProp != null)
{
return true;
}
phase = ReservedProperty.ID_MULTIPLEX;
}
if (phase == ReservedProperty.ID_MULTIPLEX)
{
if (multiplexProp != null)
{
return true;
}
phase = fields == null ? -1 : fields.nextSetBit(0);
}
return phase != -1;
}
@Override
public Property next()
{
if (!hasNext())
{
throw new NoSuchElementException();
}
if (phase == ReservedProperty.ID_PRIMARY_KEY)
{
if (recidProp == null)
{
throw new NoSuchElementException();
}
phase = ReservedProperty.ID_MULTIPLEX;
return recidProp;
}
if (phase == ReservedProperty.ID_MULTIPLEX)
{
if (isTempTable() && multiplexProp == null)
{
throw new NoSuchElementException();
}
if (multiplexProp != null)
{
phase = fields == null ? -1 : fields.nextSetBit(0);
return multiplexProp;
}
else
{
phase = fields == null ? -1 : fields.nextSetBit(0);
}
}
if (phase == -1)
{
throw new NoSuchElementException();
}
Property prop = getPropertyMeta()[phase].dmoProperty;
phase = fields == null ? -1 : fields.nextSetBit(phase + 1);
return prop;
}
};
}
/**
* Hydrate a record knowing that the result-set selected some properties in a proper order.
* Presuming an implicit, order, we can simply iterate the bitset and hydrate on the indexes
* specified there.
*
* @param session
* The underlying session that generated the result-set. It is used only to emit
* load SQLs for the non-expanded extents. If this is {@code null}, the non-expanded
* extents will be skipped.
* @param resultSet
* The result-set that provides the low-level data that should be hydrated into
* the record.
* @param rsOffset
* The offset where the DMO starts. This is the case for queries that had joins,
* so the current record may not start at index 1.
* @param r
* The record to be hydrated.
*
* @return The next rsOffset, from where the next DMO in the result-set will start (if any).
*
* @throws PersistenceException
* thrown when hydrating extents fails (as it requires extra SQL queries to be run).
* @throws SQLException
* throw when failing to hydrate from the result-set.
*/
@Override
public int hydrate(Session session, ResultSet resultSet, int rsOffset, BaseRecord r)
throws PersistenceException,
SQLException
{
if (this.recidProp != null)
{
r.primaryKey(resultSet.getLong(rsOffset++));
if (count == 1)
{
// optimize projection queries
return rsOffset;
}
}
if (this.multiplexProp != null)
{
((TempRecord) r)._multiplex(resultSet.getInt(rsOffset++));
}
if (fields != null)
{
for (int i = fields.nextSetBit(0); i != -1; i = fields.nextSetBit(i + 1))
{
rsOffset += r.readProperty(i, resultSet, rsOffset);
}
}
if (hasExtents && session != null)
{
// this is incomplete, so set the record offset to -1
hydrateExtents(session, r, -1);
}
return rsOffset;
}
}