Math Expression

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Description

The Math Expression Evaluator processor allows you to perform mathematical calculations on numerical fields using the Apache Commons JEXL library. It:

• Evaluates mathematical expressions
• Supports complex calculations
• Provides access to Java Math functions
• Creates new fields with calculation results

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Required Input

The processor requires an input event stream containing at least one numerical field to perform calculations on.

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Configuration

See more about JEXL syntax at https://commons.apache.org/proper/commons-jexl/index.html.

Additional Fields

For each calculation, you need to specify:

• Field Name: The name of the new field that will store the calculation result
• Expression: The mathematical expression to evaluate using JEXL syntax

Expression Syntax

The processor supports:

• Basic arithmetic operations (+, -, *, /)
• Mathematical functions from java.lang.Math
• References to input field values
• Complex expressions with multiple operations

Output

The processor forwards the input event with additional fields containing the calculation results.

Example

Input Event

{
  "temperature": 10.1,
  "flowrate": 2
}

Configuration

• Field Name: result1

• Expression: temperature+12

• Field Name: result2

• Expression: temperature*flowrate

Output Event

{
  "temperature": 10.1,
  "flowrate": 2,
  "result1": 22.1,
  "result2": 20.2
}

Use Cases

1. Data Transformation

   • Convert units
   • Calculate derived metrics
   • Normalize values
   • Scale measurements

2. Statistical Analysis

   • Calculate averages
   • Compute standard deviations
   • Perform trend analysis
   • Generate statistical metrics

3. Business Logic

   • Calculate costs
   • Compute performance metrics
   • Evaluate business rules
   • Generate derived values

Notes

• All input fields are available as variables in expressions
• The Math class is available for advanced calculations
• Results are stored as double-precision floating-point numbers
• Expressions are evaluated for each incoming event
• Invalid expressions will be logged as errors
• The processor preserves all input fields