Implementation:Apache Shardingsphere PreciseColumnShadowValue DTO

Knowledge Sources	Apache_Shardingsphere
Domains	Shadow_Testing, SPI
Last Updated	2026-02-10 00:00 GMT

Overview

Immutable value object carrying column shadow context for shadow algorithm evaluation.

Description

PreciseColumnShadowValue<T> is a generic final class that bundles the context needed by ColumnShadowAlgorithm implementations: the logical table name, the SQL operation type, the shadow column name, and the actual column value from the SQL statement. Uses Lombok @RequiredArgsConstructor and @Getter.

Usage

This DTO is constructed by the shadow routing engine and passed to ColumnShadowAlgorithm.isShadow() during shadow routing evaluation.

Code Reference

Source Location

• Repository: Apache_Shardingsphere
• File: features/shadow/api/src/main/java/org/apache/shardingsphere/shadow/spi/column/PreciseColumnShadowValue.java
• Lines: 1-41

Signature

@RequiredArgsConstructor
@Getter
public final class PreciseColumnShadowValue<T> implements ShadowValue {

    private final String tableName;

    private final ShadowOperationType shadowOperationType;

    private final String columnName;

    private final T value;
}

Import

import org.apache.shardingsphere.shadow.spi.column.PreciseColumnShadowValue;

I/O Contract

Inputs

Name	Type	Required	Description
tableName	String	Yes	Logical table name
shadowOperationType	ShadowOperationType	Yes	SQL operation type (INSERT, UPDATE, etc.)
columnName	String	Yes	Shadow column name
value	T	Yes	Actual column value from SQL

Outputs

Name	Type	Description
getTableName()	String	Logical table name
getShadowOperationType()	ShadowOperationType	SQL operation type
getColumnName()	String	Shadow column name
getValue()	T	Column value

Usage Examples

import org.apache.shardingsphere.shadow.spi.column.PreciseColumnShadowValue;
import org.apache.shardingsphere.shadow.spi.ShadowOperationType;

// Construct a shadow value for INSERT with column "shadow_flag" = 1
PreciseColumnShadowValue<Integer> shadowValue = new PreciseColumnShadowValue<>(
    "t_order", ShadowOperationType.INSERT, "shadow_flag", 1);

// Access fields
String table = shadowValue.getTableName();         // "t_order"
String column = shadowValue.getColumnName();        // "shadow_flag"
Integer val = shadowValue.getValue();               // 1

Related Pages

• Principle:Apache_Shardingsphere_Column_Based_Routing