Interface PropertyRef<T,V>

Type Parameters:
T - the bean type
V - the property type
All Superinterfaces:
Function<T,V>, Serializable, com.vaadin.flow.function.SerializableFunction<T,V>, com.vaadin.flow.function.ValueProvider<T,V>
All Known Implementing Classes:
PropertyRef.Nested
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface PropertyRef<T,V> extends com.vaadin.flow.function.ValueProvider<T,V>
A reference to a bean property, expressed as a method reference to its getter, instead of the property name as a String.

The main point is to get compile time safety and refactoring support for APIs that traditionally take property names as strings: 

grid.setColumns(Person::getFirstName, Person::getLastName);

The property name is resolved from the method reference at runtime, using the SerializedLambda that the JVM creates for serializable lambdas (all Vaadin functional interfaces are serializable). The name resolution is cached per method reference call site, see PropertyRefs.

Nested properties can be expressed by chaining: 

grid.setColumns(PropertyRef.of(Person::getAddress).then(Address::getStreet));

Note that only actual method references work, a lambda expression like p -> p.getFirstName() carries no property name and fails fast with an IllegalArgumentException.

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static class 
    PropertyRef.Nested<T,M,V>
    A nested property reference, created by then(PropertyRef).

  • Method Summary

    Modifier and Type
    Method
    Description
    default String
    getPropertyName()
    Resolves the name of the property this reference points to.
    static <T,V> PropertyRef<T,V>
    of(PropertyRef<T,V> getterReference)
    Helper to give the compiler a target type for a method reference, needed to start a nested property path.
    default <U> PropertyRef<T,U>
    then(PropertyRef<V,U> nested)
    Creates a reference to a nested property.

    Methods inherited from interface Function

    andThen, compose

    Methods inherited from interface com.vaadin.flow.function.ValueProvider

    apply

  • Method Details

    • getPropertyName

      default String getPropertyName()
      Resolves the name of the property this reference points to. A getter named getFoo/isFoo maps to foo, other method names (like record accessors) are used as such.
      Returns:
      the property name, potentially a dot separated path for nested references created with then(PropertyRef)

    • then

      default <U> PropertyRef<T,U> then(PropertyRef<V,U> nested)
      Creates a reference to a nested property.
      Type Parameters:
      U - the type of the nested property
      Parameters:
      nested - the reference to the property in the type of this property
      Returns:
      a reference whose property name is a dot separated path

    • of

      static <T,V> PropertyRef<T,V> of(PropertyRef<T,V> getterReference)
      Helper to give the compiler a target type for a method reference, needed to start a nested property path.
      Type Parameters:
      T - the bean type
      V - the property type
      Parameters:
      getterReference - the method reference to the getter
      Returns:
      the reference as such