ConditionalOnExpression class

Registers a bean only when an expression evaluates to true.

For a rule the other conditions cannot express, such as a combination of several properties. The expression is in SpEL, the expression language of spring_core_dart; ${...} placeholders are replaced by property values first. It may be written with or without #{...} and is evaluated with the bean factory's expression resolver, so it can refer to environment and to beans registered so far. A null result counts as false; any other non-boolean result fails the start. Prefer ConditionalOnProperty when it is enough: it is easier to read.

// Only when caching is on (the default) and the shop runs in the EU.
@Bean()
@ConditionalOnExpression(r"${app.cache:true} and '${app.mode}' == 'eu'")
Cache cache() => Cache();

Spring (Java): @ConditionalOnExpression("${app.cache:true} and '${app.mode}' == 'eu'").

Implemented types

• Condition

Constructors

ConditionalOnExpression([String expression = 'true'])

Checks expression; without one it always matches.

const

Properties

expression → String

The SpEL expression that must give true, with or without #{...}.

final

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

Methods

matches(ConditionContext context) → bool

Whether the annotated bean should be registered; context gives access to the configuration and the definitions registered so far.

override

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

toString() → String

A string representation of this object.

override

Operators

operator ==(Object other) → bool

The equality operator.

inherited