RowStructure.java
/*
** Module : RowStructure.java
** Abstract : Defines a row structure in a query.
**
** Copyright (c) 2020-2023, Golden Code Development Corporation.
**
** -#- -I- --Date-- ----------------------------------------Description---------------------------------------
** 001 CA 20200615 Created initial version.
** 002 SBI 20221031 Added a "fields" member. It is used as a storage of fields of "select" query.
** 003 AL2 20231123 Refactored this as an interface. Moved implementation in AbstractRowStructure.
** AL2 20231211 Added getDmoMeta.
*/
/*
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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.
**
** 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
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*/
package com.goldencode.p2j.persist.orm;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Iterator;
import com.goldencode.p2j.persist.DataModelObject;
import com.goldencode.p2j.persist.PersistenceException;
/**
* Defines a row structure in a SELECT query. There are multiplex flavors of such structure, most of them
* attempting to optimize the hydration or representation of selected fields. Refer to
* {@link FullRowStructure} for an example of structure that represents the "select all" attempt.
*
* Non-expanded properties are logically part of this structure, but will only affect the {@link #hasExtents()}
* flag. In other words, non-expanded properties will be hydrated only if a non-expanded property is appended,
* making {@link #hasExtents()} return true (or use {@link #forceExtents}.
* Otherwise, non-expanded extents won't be hydrated.
*/
public interface RowStructure
{
/**
* The DMO class whose properties are included in this structure.
*
* @return The DMO class underlying this structure.
*/
public Class<? extends DataModelObject> getDmoClass();
/**
* 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.
*/
public boolean addRecid(Property recid);
/**
* 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.
*/
public boolean addMultiplex(Property multiplex);
/**
* 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.
*/
public boolean addProperty(Property prop);
/**
* 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.
*/
public int getCount();
/**
* 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.
*/
public Iterator<Property> getProps();
/**
* Check if this structure requires a hydration of non-expanded extent properties. This will only return true
* if a non-expanded extent property was ever added through {@link #addProperty} or {@link #forceExtents()} was
* called.
*
* @return {@code true} if this structure will also hydrate non-expanded properties.
*/
public boolean hasExtents();
/**
* Force the non-expanded extents to be hydrated.
*/
public void forceExtents();
/**
* The core hydration logic based on the row structure. This class is specialized in traversing the
* result-set and populating the record with the data found 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.
*/
public int hydrate(Session session, ResultSet resultSet, int rsOffset, BaseRecord r)
throws PersistenceException,
SQLException;
/**
* Retrieve the DMO meta used by the underlying DMO of this structure.
*
* @return The DMO meta of the DMO used by this row structure
*/
public DmoMeta getDmoMeta();
/**
* Check if the structure is incomplete. Most implementations are hydrate the record partially,
* except for {@link FullRowStructure}.
*
* @return {@code true} by default.
*/
public default boolean isIncomplete()
{
return true;
}
}