> ## Documentation Index
> Fetch the complete documentation index at: https://aletyx.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Decision Tables

> Set up a Drools decision tables project - Maven dependencies (drools-decisiontables, Apache POI for Excel), the .drl.xls/.xlsx/.csv naming requirement, and project structure.

## Getting Started with Drools Decision Tables

## Project Setup

Before diving into decision tables, you need to set up your Java project with the necessary dependencies. This guide will walk you through the process step by step.

### Maven Configuration

Below is a complete `pom.xml` configuration you can use as a starting point for your Drools decision table project:

```xml theme={null}
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>ai.aletyx.example</groupId>
    <artifactId>drools-decision-tables</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>17 </maven.compiler.source>
        <maven.compiler.target>17</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <drools.version>10.1.0</drools.version>
        <slf4j.version>2.0.9</slf4j.version>
    </properties>

    <dependencies>
        <!-- Drools Dependencies -->
        <dependency>
            <groupId>org.kie</groupId>
            <artifactId>kie-api</artifactId>
            <version>${drools.version}</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-core</artifactId>
            <version>${drools.version}</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-compiler</artifactId>
            <version>${drools.version}</version>
        </dependency>
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-mvel</artifactId>
            <version>${drools.version}</version>
        </dependency>

        <!-- Decision Tables -->
        <dependency>
            <groupId>org.drools</groupId>
            <artifactId>drools-decisiontables</artifactId>
            <version>${drools.version}</version>
        </dependency>

        <!-- Required for Excel support -->
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>5.2.3</version>
        </dependency>
        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi-ooxml</artifactId>
            <version>5.2.3</version>
        </dependency>

        <!-- Logging Dependencies -->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-api</artifactId>
            <version>${slf4j.version}</version>
        </dependency>
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-simple</artifactId>
            <version>${slf4j.version}</version>
        </dependency>

        <!-- Testing -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.13.2</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.11.0</version>
                <configuration>
                    <source>${maven.compiler.source}</source>
                    <target>${maven.compiler.target}</target>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>
```

<Warning>
  **Drools Excel Spreadsheet Filename Change Requirement**

  **Important Note**: When migrating from Drools 7 or earlier, spreadsheet decision table files must use the extension `.drl.xls`, `.drl.xlsx`, or `.drl.csv`. This is important to note as historically in earlier versions of Drools, you could use `decisiontable.xls` and the project would incorporate them, now they must be explicitly defined this way. This does not affect usage in your spreadsheet editor of choice, it is mainly designed as a semantical parser/cpompiler requirement to Drools.
</Warning>

<Note>
  **Potential Logging Error: StatusLogger Log4j2 could not find a loggin implementation**

  When including `drools-decisiontables` in your project, you might encounter the following error:
  `ERROR StatusLogger Log4j2 could not find a logging implementation
    `

  This happens because Apache POI (used to process spreadsheet files) uses the Log4j API. To avoid this error, you need to include either:

  1. The SLF4J adapter (included in the above POM)
  2. 2. Or the Log4j 2 SLF4J Binding, if you're using Log4j as your logging backend
</Note>

### Project Structure

Here's a recommended project structure for a basic Drools decision table application:

```text theme={null}
src/
├── main/
│   ├── java/
│   │   └── com/
│   │       └── example/
│   │           ├── model/
│   │           │   └── Order.java
│   │           └── DecisionTableExample.java
│   └── resources/
│       └── rules/
│           └── ShippingCharges.drl.xlsx
└── test/
    └── java/
        └── com/
            └── example/
                └── DecisionTableTest.java
```

## Next Steps

Now that you have your project set up, continue to the next section to create your first decision table in Excel.