BlobType.java
/*
** Module : BlobType.java
** Abstract : Handles conversion from/to SQL/FWD blob type.
**
** Copyright (c) 2019-2024, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 OM 20191101 Created initial version.
** OM 20221117 Some properties (datetime-tz) may take a different number of positional parameters when
** used in insert/update or where predicate.
** 002 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 003 TJD 20240123 Java 17 compatibility updates
*/
/*
** 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
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** Affero GPL version 3 and may not be removed by you.
**
** 0. Attribution Requirement.
**
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**
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*/
package com.goldencode.p2j.persist.orm.types;
import com.goldencode.p2j.persist.Record;
import com.goldencode.p2j.persist.orm.*;
import com.goldencode.p2j.util.*;
import com.goldencode.p2j.util.logging.*;
import java.sql.*;
/** This object handles conversion from/to SQL/FWD {@code blob} type. */
public class BlobType
implements DataHandler
{
/** Logger */
private static final CentralLogger LOG = CentralLogger.get(BlobType.class);
/**
* Creates and returns a new {@link blob} from a SQL counterpart.
*
* @param sqlVal
* A value obtained from a SQL query, which needs to be converted to a
* {@code BaseDataType}.
*
* @return A FWD {@code blob} object representing the same value as {@code sqlVal}.
*/
@Override
public blob convert(Object sqlVal)
{
// TODO: test implementation
blob ret;
try
{
ret = new blob((Blob) sqlVal);
}
catch (SQLException e)
{
LOG.warning("", e);
ret = new blob();
ret.setUnknown();
}
return ret;
}
/**
* Use the data from a {@code blob} field stored in {@code BaseRecord.data} and use it to
* initialize a parameter of type blob in a SQL prepared query.
*
* @param stmt
* The prepared statement whose parameter is to be set.
* @param index
* The index/position of the parameter.
* @param val
* The value of the parameter. Must be a {@code blob}.
* @param forUpdate
* {@code true} if the parameter in the statement is used to update a field and {@code false} if
* it is used as part of the where predicate. Ignored here.
*
* @return 1 (the number of position used by this value).
*
* @throws SQLException
* when an error is encountered while setting the value.
*/
@Override
public int setParameter(PreparedStatement stmt, int index, Object val, boolean forUpdate)
throws SQLException
{
return TypeManager.setBlobParameter(stmt, index, val, forUpdate);
}
/**
* Reads data from one or more positions from the {@code ResultSet}, eventually converting it
* to a proper type and storing the result directly to the {@code Record}'s data structure.
*
* @param rs
* The {@code ResultSet} to read from.
* @param rsOffset
* The index/position in current row of {@code rs} to start reading.
* @param data
* The destination. Ie. the record's {@code data} field member.
* @param propIndex
* The destination offset. Ie. the property index.
*
* @return always 1.
*
* @throws SQLException
* when an error is encountered while setting the value.
*/
@Override
public int readProperty(ResultSet rs, int rsOffset, Object[] data, int propIndex)
throws SQLException
{
Connection conn = rs.getStatement().getConnection();
boolean isAutoCommit = conn.getAutoCommit();
try
{
conn.setAutoCommit(false);
Blob blob = rs.getBlob(rsOffset);
if (rs.wasNull())
{
data[propIndex] = null;
}
else
{
blob b = new blob(blob);
data[propIndex] = b.getByteArray();
}
}
finally
{
conn.setAutoCommit(isAutoCommit);
}
return 1;
}
/**
* Instantiate a low-level initial value suitable for storage in a {@link BaseRecord}'s data
* array, parsed from a string representation.
*
* @param text
* String representation of the initial value.
* @param meta
* Property metadata.
*/
@Override
public Object initialValue(String text, PropertyMeta meta)
{
// the default value for blob is always the unknown value
return null;
}
/**
* Compute the size in bytes taken by a specified value for the data type handled by this
* class. The returned value is used to compute the index size.
*
* @param val
* The value to be computed the size. Assumed to be a {@code Blob}.
*
* @return the number of bytes the {@code val} object occupies.
*/
@Override
public int getFieldSizeInIndex(Object val)
{
if (val == null)
{
return 3;
}
return ((byte[]) val).length;
}
/**
* Sets a value of a property in a {@code Record}. The specified value is converted from
* {@code BaseDataType} FWD standard to plain Java, as the {@code data} array expects before
* assigning the value to right offset.
*
* @param data
* The {@code data} array of the record to be altered.
* @param val
* The {@code BaseDataType} value to be set. Assumed to be a {@code blob}.
* @param offset
* The offset of the property, ie, the entry in {@code data} array. This includes both
* base property offset and the eventual extent index.
* @param meta
* Property metadata. Used to fine-tune stored data.
*/
@Override
public void setField(Object[] data, BaseDataType val, int offset, PropertyMeta meta)
{
if (val == null || val.isUnknown())
{
data[offset] = null;
return;
}
blob asBDT = (blob) val;
data[offset] = asBDT.getByteArray();
}
/**
* Obtain the value of the property of a {@code Record} located at a specified offset in {@code data}
* array. It assumes the data at specified offset is compatible with this data handler.
*
* @param r
* The {@code Record}.
* @param offset
* The offset.
*
* @return The value requested wrapped as a {@code BaseDataType}.
*/
@Override
public BaseDataType getField(Record r, int offset)
{
return r._getBlob(offset);
}
}