TargetLob.java
/*
** Module : TargetLob.java
** Abstract : A target parameter to a LobCopy operation.
**
** Copyright (c) 2019-2025, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 ECF 20190510 Created initial version.
** 002 ECF 20190706 Implemented COPY-LOB runtime.
** 003 CA 20190717 Automatically resize a memptr target if the source doesn't fit.
** 004 CA 20191203 Fixed overlay and unknown COPY-LOB related bugs.
** 005 OM 20210128 Reset the size of memptr to 0 before reallocating.
** OM 20210312 Fixed support for LOBs obtained by dereference operator.
** OM 20210328 Improved copy lob engine and validations.
** OM 20210404 Fine-tuned errors generated by edge-case in copy-lob statements.
** EVL 20220405 Added validateOffset implementation.
** EVL 20220408 Refined error messages emission for different source types.
** EVL 20220411 Removed TODO for error generation.
** 006 EVL 20230317 Adding support for longchar internal length override.
** 007 GBB 20230512 Logging methods replaced by CentralLogger/ConversionStatus.
** 008 CA 20250321 The TARGET of COPY-LOB can also be a class property.
*/
/*
** 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.
**
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**
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*/
package com.goldencode.p2j.util;
import com.goldencode.p2j.persist.*;
/**
* Concrete implementation of a converted COPY-LOB target parameter, corresponding with the
* {@code TO [ OBJECT ] target-lob} phrase.
*/
public class TargetLob
extends LobCopyOutput
{
/** Large object which is the target of the copy operation */
private final LargeObject lob;
/** Field or property reference to LOB, if LOB is a record buffer field or a class property */
private final Accessor field;
/** 1-based offset at which data will be written into the target large object */
private NumberType offset = null;
/** If {@code true}, truncate any data remaining in the target, which was not overwritten */
private boolean trim = false;
/**
* Constructor.
*
* @param lob
* Large object which is the target of the copy operation.
*/
public TargetLob(LargeObject lob)
{
FieldReference tmpField = null;
if (lob != null)
{
tmpField = lob.getFieldReference();
if (tmpField != null)
{
lob.setFieldReference(null); // reset at first use
}
}
this.field = tmpField;
this.lob = lob;
}
/**
* Constructor which takes an object that is expected to be a LOB. Intended to handle the
* converted POLY case.
*
* @param lob
* Large object which is the target of the copy operation.
*
* @throws ConditionException
* if {@code lob} is not an instance of @LargeObject@.
*/
public TargetLob(Object lob)
{
this(LobCopy.assertParameterType(lob));
}
/**
* Constructor which takes a field reference which must be a wrapper for a {@code LargeObject}.
*
* @param field
* Field reference to a large object which is the target of the copy operation.
*/
public TargetLob(FieldReference field)
{
this.field = field;
this.lob = (LargeObject) field.get();
}
/**
* Constructor which takes a property reference which must be a wrapper for a {@code LargeObject}.
*
* @param property
* Property reference to a large object which is the target of the copy operation.
*/
public TargetLob(PropertyReference property)
{
this.field = property;
this.lob = (LargeObject) property.get();
}
/**
* Set the starting offset at which to write content; corresponds with the OVERLAY AT option.
*
* @param offset
* 1-based starting offset.
*
* @return This object instance, to allow method chaining.
*/
public TargetLob offset(NumberType offset)
{
this.offset = offset;
return this;
}
/**
* Set the starting offset at which to write content; corresponds with the OVERLAY AT option.
*
* @param offset
* 1-based starting offset.
*
* @return This object instance, to allow method chaining.
*/
public TargetLob offset(int offset)
{
this.offset = new integer(offset);
return this;
}
/**
* Configure the copy operation to trim any data remaining in the target object which was not
* overwritten by the copy.
*
* @return This object instance, to allow method chaining.
*/
public TargetLob trim()
{
this.trim = true;
return this;
}
/**
* Indicate whether this object is a valid large object data type. It is possible to pass a
* POLY which is not a valid LOB type as a COPY-LOB parameter, and this error must be
* determined at runtime.
*
* @return {@code true} if valid, else {@code false}. The default implementation assumes
* validity; implementors which must handle runtime type verification must override
* this method.
*/
@Override
public boolean isLargeObject()
{
return lob != null;
}
/**
* Obtain the type of the object wrapped by this parameter
*
* @return The numerical id of a type declared as one of the TYPE static constants from
* {@code LobCopyParameter} interface.
*/
@Override
public int getObjectType()
{
return (lob instanceof clob) ? TYPE_CLOB : // must be checked first
(lob instanceof blob) ? TYPE_BLOB :
(lob instanceof memptr) ? TYPE_MEMPTR :
(lob instanceof longchar) ? TYPE_LONGCHAR : TYPE_UNKNOWN;
}
/**
* Indicate whether the large object represented by this parameter natively represents
* encoded character data, as opposed to binary data.
*
* @return {@code true} if character data; {@code false} if binary data.
*/
@Override
public boolean isCharacterData()
{
return lob != null && lob.isCharacterData();
}
/**
* Get the code page of this parameter, if any.
*
* @return 4GL code page name or {@code null} if parameter represents non-character data.
*/
@Override
public String getCodePage()
{
return LobCopy.getLobDefaultCodePage(lob);
}
/**
* Checks if the optional offset is valid.
*
* @param sourceType
* The type of the source object. The error messages are different in some cases.
*
* @return {@code true} if the optional offset is valid.
*/
@Override
public boolean validateOffset(int sourceType)
{
if (offset != null)
{
int objectType = getObjectType();
if ((offset.isUnknown() || offset.intValue() <= 0) &&
objectType == TYPE_MEMPTR && sourceType == TYPE_CLOB)
{
ErrorManager.recordOrThrowError(11332);
// Invalid offset specified in COPY-LOB statement. (11332)
return false;
}
}
return true;
}
/**
* Validate this parameter. The following parameters are checked: offset,
*
* @param sourceType
* The type of the source object. The error messages are different in some cases.
*
* @return {@code true} if validation did not encounter any issue and {@code false} otherwise, when in
* NO-ERROR mode and the {@code ErrorConditionException} is not thrown.
*
* @throws ErrorConditionException
* if the parameter fails validation and silent error mode is not active.
*/
@Override
public boolean validate(int sourceType)
{
int objectType = getObjectType();
if (offset != null)
{
if (offset.isUnknown() || offset.intValue() <= 0)
{
ErrorManager.recordOrThrowError(11332);
// Invalid offset specified in COPY-LOB statement. (11332)
return false;
}
if (sourceType == TYPE_MEMPTR && objectType == TYPE_MEMPTR)
{
if (((memptr)lob).isUninitialized())
{
ErrorManager.recordOrThrowError(11393);
// MEMPTR target of COPY-LOB must be initialized. (11393)
return false;
}
}
}
int off = getOffset();
long size = lob.lengthOf();
if (off > size)
{
if (objectType == TYPE_LONGCHAR)
{
// this is fine: this type of variable will 'expand' as needed to accommodate the larger offset
return true;
}
else if (objectType == TYPE_MEMPTR)
{
// different errors depending on different conditions
if (sourceType == TYPE_FILE)
{
ErrorManager.recordOrThrowError(11335);
}
else if (sourceType == TYPE_LONGCHAR)
{
ErrorManager.recordOrThrowError(11393);
}
else
{
ErrorManager.recordOrThrowError(11394);
}
// MEMPTR target of COPY-LOB is not big enough. (11394)
return false;
}
else if (objectType == TYPE_BLOB || objectType == TYPE_CLOB)
{
ErrorManager.recordOrThrowError(11335);
// Offset supplied for target large object is greater than object size. (11335)
return false;
}
}
// everything seems fine now
return true;
}
/**
* Write the given array of bytes into the large object.
*
* @param data
* Data to be assigned to this object.
*/
@Override
public void write(byte[] data)
{
int off = getOffset();
if (!checkTargetSize(off, data == null ? 0 : data.length))
{
return;
}
lob.write(isOverlay(), data, off, trim);
if (field != null)
{
field.set((BaseDataType) lob);
}
}
/**
* Write the given character data into the large object.
*
* @param data
* Data to be assigned to this object.
* @param oecp
* Target OE codepage to be used in write operation. Ignored.
*/
@Override
public void write(String data, String oecp)
{
int off = getOffset();
lob.write(isOverlay(), data, off, trim);
if (field != null)
{
field.set((BaseDataType) lob);
}
}
/**
* Get the offset at which to overlay data in the target. If no explicit offset has been
* specified, return a value of 0.
*
* @return Zero-based target offset.
*/
private int getOffset()
{
return offset != null ? offset.intValue() - 1 : 0;
}
/**
* Check if the OVERLAY option is used.
*
* @return <code>true</code> of {@link #offset} is non-null.
*/
protected boolean isOverlay()
{
return offset != null;
}
/**
* Sets new value for longchar overridden length. Can be more than backend String variable and sets up
* in copy-lob operation in some conditions.
*
* @param newOverrideLength
* The new value of the internal longchar length.
*/
protected void setOverrideLength(int newOverrideLength)
{
if (lob instanceof longchar)
{
((longchar)lob).setOverrideLength(newOverrideLength >= 0 ? newOverrideLength + getOffset() : -1);
}
}
/**
* Check the target size, and resize if it doesn't fit.
*
* @param offset
* The offset where to write in the target.
* @param srcLength
* The source length.
*
* @return {@code true} if the target passed validation.
*/
private boolean checkTargetSize(int offset, int srcLength)
{
if (lob instanceof memptr)
{
memptr m = (memptr) lob;
if (m.isUninitialized() || m.isUnknown())
{
m.setLength(offset + srcLength);
}
else
{
long lobSize = m.lengthOf();
if (lobSize < offset + srcLength)
{
if (!isOverlay())
{
m.setLength(0); // reset first, otherwise resize won't work
m.setLength(offset + srcLength);
}
else
{
ErrorManager.recordOrThrowError(11394);
// MEMPTR target of COPY-LOB is not big enough. (11394)
return false;
}
}
}
}
return true;
}
}