BufferCompare.java
/*
** Module : BufferCompare.java
** Abstract : A configurable buffer comparison operation.
**
** Copyright (c) 2019-2021, Golden Code Development Corporation.
**
** -#- -I- --Date-- ---------------------------------------Description---------------------------------------
** 001 ECF 20190208 Created initial version to simplify API for BUFFER-COMPARE operations.
** 002 OM 20210225 Fixed Mode.fromString() method. Avoid NPE in run().
*/
/*
** 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.
**
** You must preserve all legal notices or author attributions in the covered
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** credit already included within the covered work.
**
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**
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*/
package com.goldencode.p2j.persist;
import java.util.*;
import com.goldencode.p2j.util.*;
/**
* Object which performs a buffer comparison operation. All configuration methods return the
* current object instance, to allow method chaining.
*
* TODO: add support for EXPLICIT COMPARES expressions.
*/
public class BufferCompare
{
/** Comparison mode types */
public static enum Mode
{
/** The default mode, aka "case-neutral". */
DEFAULT("case-neutral"),
/** The case-sensitive mode. */
CASE_SENSITIVE("case-sensitive"),
/** The binary compare mode. */
BINARY("binary");
/** Internal name */
private final String name;
/**
* Constructor.
*
* @param name
* Internal name.
*/
Mode(String name)
{
this.name = name;
}
/**
* Helper method to determine mode from a string.
*
* @param modeString
* Text representation of a buffer compare mode.
*
* @return Appropriate mode constant for the given string.
*
* @throws ErrorConditionException
* if the given string doesn't match a constant.
*/
static Mode fromString(character modeString)
{
if (modeString == null || modeString.isUnknown())
{
return DEFAULT;
}
switch (modeString.getValue().trim().toLowerCase())
{
case "case-sensitive":
return CASE_SENSITIVE;
case "binary":
return BINARY;
default:
// no error is generated if invalid compare mode is passed
return DEFAULT;
}
}
/**
* Obtain a short description of this compare mode.
*
* @return a short description of this compare mode.
*/
@Override
public String toString()
{
return name;
}
}
/** "Left" object of the comparison */
private final DataModelObject dmo1;
/** "Right" object of the comparison */
private final DataModelObject dmo2;
/** {@code true} if {@code fields} should be excluded; {@code false} for them to be included */
private boolean exclusive = true;
/** {@code true} to compare all fields; {@code false} to halt at the first difference */
private boolean exhaustive = false;
/** Optional field names to include or exclude from comparison */
private String[] fields = null;
/** Comparison mode */
private Mode mode = Mode.DEFAULT;
/** Delegate which sets the results of the comparison into a results object */
private Accessor resultDelegate = null;
/** {@code true} to skip any LOBs when performing comparison; {@code false} to include them */
private boolean noLobs = false;
/**
* Constructor which accepts DMOs to compare.
*
* @param dmo1
* "Left" object of the comparison.
* @param dmo2
* "Right" object of the comparison.
*/
public BufferCompare(DataModelObject dmo1, DataModelObject dmo2)
{
this.dmo1 = dmo1;
this.dmo2 = dmo2;
}
/**
* Exclude the given fields from the comparison. Include all others (except LOBs if {@code
* #noLobs()} was invoked).
*
* @param fields
* List of legacy field names to exclude.
*
* @return This object instance.
*/
public BufferCompare except(String... fields)
{
this.exclusive = true;
this.fields = fields;
return this;
}
/**
* Include only the given fields for the comparison. Exclude all others.
*
* @param fields
* List of legacy field names to include.
*
* @return This object instance.
*/
public BufferCompare using(String... fields)
{
this.exclusive = false;
this.fields = fields;
return this;
}
/**
* Configure a case-sensitive comparison (only relevant for character and CLOB fields).
*
* @return This object instance.
*/
public BufferCompare caseSensitive()
{
mode = Mode.CASE_SENSITIVE;
return this;
}
/**
* Configure a binary comparison.
*
* @return This object instance.
*/
public BufferCompare binary()
{
mode = Mode.BINARY;
return this;
}
/**
* Set the target object into which a boolean result of the comparison will be stored. The
* result will be {@code true} if all compared fields matched; else {@code false}.
*
* @param target
* Result target.
*
* @return This object instance.
*/
public BufferCompare saveResultIn(logical target)
{
this.exhaustive = false;
this.resultDelegate = new AccessorWrapper(target);
return this;
}
/**
* Set the target object into which a text result of the comparison will be stored. The result
* will be a list of the legacy names of fields, if any, whose values did not match.
*
* @param target
* Result target.
*
* @return This object instance.
*/
public BufferCompare saveResultIn(character target)
{
this.exhaustive = true;
this.resultDelegate = new AccessorWrapper(target);
return this;
}
/**
* Set the target field into which a result of the comparison will be stored. The type of the
* field must be {@code logical} or {@code character}. If {@code logical}, the result will be
* {@code true} if all compared fields matched; else {@code false}. If {@code character}, the
* result will be a list of the names of legacy fields, if any, whose values did not match.
*
* @param target
* Result target.
*
* @return This object instance.
*/
public BufferCompare saveResultIn(FieldReference target)
{
this.exhaustive = character.class.isAssignableFrom(target.getType());
this.resultDelegate = target;
return this;
}
/**
* Exclude any LOB fields from the comparison. If the buffer record contains no LOB fields,
* this option has no effect.
*
* @return This object instance.
*/
public BufferCompare noLobs()
{
this.noLobs = true;
return this;
}
/**
* Perform the comparison. This method should only be invoked once all configuration methods
* have been invoked. In the typical use pattern, this method is called at the end of the
* method chain which starts with {@code new BufferCompare(dmo1, dmo2)}.
*/
public void run()
{
// if no result target was configured, the comparison is avoided, since there is no way to
// retrieve the result, and there are no side effects of the comparison
// TODO: this could change, once EXPLICIT COMPARES expressions are supported
if (resultDelegate == null)
{
return;
}
List<String> diffs = RecordBuffer.compare(dmo1, dmo2, fields, noLobs, mode, exclusive, exhaustive);
if (diffs == null || diffs.isEmpty())
{
if (exhaustive)
{
resultDelegate.set(new character(""));
}
else
{
resultDelegate.set(new logical(true));
}
}
else
{
if (exhaustive)
{
// use the P4GL simple comma-separated list format
StringBuilder buf = new StringBuilder();
for (String next : diffs)
{
if (buf.length() > 0)
{
buf.append(',');
}
buf.append(next);
}
resultDelegate.set(new character(buf.toString()));
}
else
{
resultDelegate.set(new logical(false));
}
}
}
}