Operators

The Spring Expression Language supports the following kinds of operators:

Relational Operators
Logical Operators
Mathematical Operators
The Assignment Operator

Relational Operators

The relational operators (equal, not equal, less than, less than or equal, greater than, and greater than or equal) are supported by using standard operator notation. These operators work on Number types as well as types implementing Comparable. The following listing shows a few examples of operators:

Java
Kotlin

// evaluates to true
boolean trueValue = parser.parseExpression("2 == 2").getValue(Boolean.class);

// evaluates to false
boolean falseValue = parser.parseExpression("2 < -5.0").getValue(Boolean.class);

// evaluates to true
boolean trueValue = parser.parseExpression("'black' < 'block'").getValue(Boolean.class);

// uses CustomValue:::compareTo
boolean trueValue = parser.parseExpression("new CustomValue(1) < new CustomValue(2)").getValue(Boolean.class);

// evaluates to true
val trueValue = parser.parseExpression("2 == 2").getValue(Boolean::class.java)

// evaluates to false
val falseValue = parser.parseExpression("2 < -5.0").getValue(Boolean::class.java)

// evaluates to true
val trueValue = parser.parseExpression("'black' < 'block'").getValue(Boolean::class.java)

// uses CustomValue:::compareTo
val trueValue = parser.parseExpression("new CustomValue(1) < new CustomValue(2)").getValue(Boolean::class.java);

Greater-than and less-than comparisons against null follow a simple rule: null is treated as nothing (that is NOT as zero). As a consequence, any other value is always greater than null (X > null is always true) and no other value is ever less than nothing (X < null is always false).

If you prefer numeric comparisons instead, avoid number-based null comparisons in favor of comparisons against zero (for example, X > 0 or X < 0).

In addition to the standard relational operators, SpEL supports the instanceof and regular expression-based matches operator. The following listing shows examples of both:

Java
Kotlin

// evaluates to false
boolean falseValue = parser.parseExpression(
		"'xyz' instanceof T(Integer)").getValue(Boolean.class);

// evaluates to true
boolean trueValue = parser.parseExpression(
		"'5.00' matches '^-?\\d+(\\.\\d{2})?$'").getValue(Boolean.class);

// evaluates to false
boolean falseValue = parser.parseExpression(
		"'5.0067' matches '^-?\\d+(\\.\\d{2})?$'").getValue(Boolean.class);

// evaluates to false
val falseValue = parser.parseExpression(
		"'xyz' instanceof T(Integer)").getValue(Boolean::class.java)

// evaluates to true
val trueValue = parser.parseExpression(
		"'5.00' matches '^-?\\d+(\\.\\d{2})?$'").getValue(Boolean::class.java)

// evaluates to false
val falseValue = parser.parseExpression(
		"'5.0067' matches '^-?\\d+(\\.\\d{2})?$'").getValue(Boolean::class.java)

Be careful with primitive types, as they are immediately boxed up to their wrapper types. For example, 1 instanceof T(int) evaluates to false, while 1 instanceof T(Integer) evaluates to true, as expected.

Each symbolic operator can also be specified as a purely alphabetic equivalent. This avoids problems where the symbols used have special meaning for the document type in which the expression is embedded (such as in an XML document). The textual equivalents are:

lt (<)
gt (>)
le (<=)
ge (>=)
eq (==)
ne (!=)
div (/)
mod (%)
not (!).

All of the textual operators are case-insensitive.

Logical Operators

SpEL supports the following logical operators:

and (&&)
or (||)
not (!)

The following example shows how to use the logical operators:

Java
Kotlin

// -- AND --

// evaluates to false
boolean falseValue = parser.parseExpression("true and false").getValue(Boolean.class);

// evaluates to true
String expression = "isMember('Nikola Tesla') and isMember('Mihajlo Pupin')";
boolean trueValue = parser.parseExpression(expression).getValue(societyContext, Boolean.class);

// -- OR --

// evaluates to true
boolean trueValue = parser.parseExpression("true or false").getValue(Boolean.class);

// evaluates to true
String expression = "isMember('Nikola Tesla') or isMember('Albert Einstein')";
boolean trueValue = parser.parseExpression(expression).getValue(societyContext, Boolean.class);

// -- NOT --

// evaluates to false
boolean falseValue = parser.parseExpression("!true").getValue(Boolean.class);

// -- AND and NOT --
String expression = "isMember('Nikola Tesla') and !isMember('Mihajlo Pupin')";
boolean falseValue = parser.parseExpression(expression).getValue(societyContext, Boolean.class);

// -- AND --

// evaluates to false
val falseValue = parser.parseExpression("true and false").getValue(Boolean::class.java)

// evaluates to true
val expression = "isMember('Nikola Tesla') and isMember('Mihajlo Pupin')"
val trueValue = parser.parseExpression(expression).getValue(societyContext, Boolean::class.java)

// -- OR --

// evaluates to true
val trueValue = parser.parseExpression("true or false").getValue(Boolean::class.java)

// evaluates to true
val expression = "isMember('Nikola Tesla') or isMember('Albert Einstein')"
val trueValue = parser.parseExpression(expression).getValue(societyContext, Boolean::class.java)

// -- NOT --

// evaluates to false
val falseValue = parser.parseExpression("!true").getValue(Boolean::class.java)

// -- AND and NOT --
val expression = "isMember('Nikola Tesla') and !isMember('Mihajlo Pupin')"
val falseValue = parser.parseExpression(expression).getValue(societyContext, Boolean::class.java)

Mathematical Operators

You can use the addition operator (+) on both numbers and strings. You can use the subtraction (-), multiplication (*), and division (/) operators only on numbers. You can also use the modulus (%) and exponential power (^) operators on numbers. Standard operator precedence is enforced. The following example shows the mathematical operators in use:

Java
Kotlin

// Addition
int two = parser.parseExpression("1 + 1").getValue(Integer.class);  // 2

String testString = parser.parseExpression(
		"'test' + ' ' + 'string'").getValue(String.class);  // 'test string'

// Subtraction
int four = parser.parseExpression("1 - -3").getValue(Integer.class);  // 4

double d = parser.parseExpression("1000.00 - 1e4").getValue(Double.class);  // -9000

// Multiplication
int six = parser.parseExpression("-2 * -3").getValue(Integer.class);  // 6

double twentyFour = parser.parseExpression("2.0 * 3e0 * 4").getValue(Double.class);  // 24.0

// Division
int minusTwo = parser.parseExpression("6 / -3").getValue(Integer.class);  // -2

double one = parser.parseExpression("8.0 / 4e0 / 2").getValue(Double.class);  // 1.0

// Modulus
int three = parser.parseExpression("7 % 4").getValue(Integer.class);  // 3

int one = parser.parseExpression("8 / 5 % 2").getValue(Integer.class);  // 1

// Operator precedence
int minusTwentyOne = parser.parseExpression("1+2-3*8").getValue(Integer.class);  // -21

// Addition
val two = parser.parseExpression("1 + 1").getValue(Int::class.java)  // 2

val testString = parser.parseExpression(
		"'test' + ' ' + 'string'").getValue(String::class.java)  // 'test string'

// Subtraction
val four = parser.parseExpression("1 - -3").getValue(Int::class.java)  // 4

val d = parser.parseExpression("1000.00 - 1e4").getValue(Double::class.java)  // -9000

// Multiplication
val six = parser.parseExpression("-2 * -3").getValue(Int::class.java)  // 6

val twentyFour = parser.parseExpression("2.0 * 3e0 * 4").getValue(Double::class.java)  // 24.0

// Division
val minusTwo = parser.parseExpression("6 / -3").getValue(Int::class.java)  // -2

val one = parser.parseExpression("8.0 / 4e0 / 2").getValue(Double::class.java)  // 1.0

// Modulus
val three = parser.parseExpression("7 % 4").getValue(Int::class.java)  // 3

val one = parser.parseExpression("8 / 5 % 2").getValue(Int::class.java)  // 1

// Operator precedence
val minusTwentyOne = parser.parseExpression("1+2-3*8").getValue(Int::class.java)  // -21

The Assignment Operator

To set a property, use the assignment operator (=). This is typically done within a call to setValue but can also be done inside a call to getValue. The following listing shows both ways to use the assignment operator:

Java
Kotlin

Inventor inventor = new Inventor();
EvaluationContext context = SimpleEvaluationContext.forReadWriteDataBinding().build();

parser.parseExpression("name").setValue(context, inventor, "Aleksandar Seovic");

// alternatively
String aleks = parser.parseExpression(
		"name = 'Aleksandar Seovic'").getValue(context, inventor, String.class);

val inventor = Inventor()
val context = SimpleEvaluationContext.forReadWriteDataBinding().build()

parser.parseExpression("name").setValue(context, inventor, "Aleksandar Seovic")

// alternatively
val aleks = parser.parseExpression(
		"name = 'Aleksandar Seovic'").getValue(context, inventor, String::class.java)