EvalEx is a handy expression evaluator for Java, that allows to parse and evaluate expression strings.
- Supports numerical, boolean, string, array and structure expressions, operations and variables.
- Array and structure support: Arrays and structures can be mixed, building arbitrary data structures.
- Uses BigDecimal for numerical calculations.
- MathContext and number of decimal places can be configured, with optional automatic rounding.
- No dependencies to external libraries.
- Easy integration into existing systems to access data.
- Predefined boolean and mathematical operators.
- Predefined mathematical, boolean and string functions.
- Custom functions and operators can be added.
- Functions can be defined with a variable number of arguments (see MIN, MAX and SUM functions).
- Supports hexadecimal and scientific notations of numbers.
- Supports implicit multiplication, e.g. (a+b)(a-b) or 2(x-y) which equals to (a+b)*(a-b) or 2*( x-y)
- Lazy evaluation of function parameters (see the IF function) and support of sub-expressions.
The full documentation for EvalEx can be found on GitHub Pages
For announcements, questions and ideas visit the Discussions area.
You can download the binaries, source code and JavaDoc jars from
Maven Central.
You will find there also copy/paste templates for including EvalEx in your project with build
systems like Maven or Gradle.
Expression expression = new Expression("1 + 2 / (4 * SQRT(4))");
EvaluationValue result = expression.evaluate();
System.out.println(result.getNumberValue()); // prints 1.25Expression expression = new Expression("(a + b) * (a - b)");
EvaluationValue result = expression
.with("a", 3.5)
.and("b", 2.5)
.evaluate();
System.out.println(result.getNumberValue()); // prints 6.00Expression expression = new Expression("level > 2 || level <= 0");
EvaluationValue result = expression
.with("level", 3.5)
.evaluate();
System.out.println(result.getBooleanValue()); // prints trueExpression expression = new Expression("\"Hello \" + name + \", you are \" + age")
.with("name","Frank")
.and("age",38);
System.out.println(expression.evaluate().getStringValue()); // prints Hello Frank, you are 38See the Documentation for more details.
Expression expression = new Expression("values[i-1] * factors[i-1]");
EvaluationValue result = expression
.with("values", List.of(2, 3, 4))
.and("factors", List.of(2, 4, 6))
.and("i", 1)
.evaluate();
System.out.println(result.getNumberValue()); // prints 4Arrays and Structures can be combined to build arbitrary data structures. See the Documentation for more details.
Map<String, Object> order = new HashMap<>();
order.put("id", 12345);
order.put("name", "Mary");
Map<String, Object> position = new HashMap<>();
position.put("article", 3114);
position.put("amount", 3);
position.put("price", new BigDecimal("14.95"));
order.put("positions", List.of(position));
Expression expression = new Expression("order.positions[x].amount * order.positions[x].price")
.with("order", order)
.and("x", 0);
BigDecimal result = expression.evaluate().getNumberValue();
System.out.println(result); // prints 44.85Copyright 2012-2022 by Udo Klimaschewski
Thanks to all who contributed to this project: Contributors
The software is licensed under the Apache License, Version 2.0 ( see LICENSE file).
- The power of operator (^) implementation was copied from Stack Overflow Thanks to Gene Marin
- The SQRT() function implementation was taken from the book The Java Programmers Guide To numerical Computing ( Ronald Mak, 2002)