Class DefaultMethodCall

  • All Implemented Interfaces:
    InstrumentedType.Prepareable, Implementation

    @Enhance
    public class DefaultMethodCall
    extends java.lang.Object
    implements Implementation
    This Implementation invokes a default method for the methods it instruments. A default method is potentially ambiguous if a method of identical signature is defined in several interfaces. For this reason, this implementation allows for the specification of prioritized interfaces whose default methods, if a method of equivalent signature is defined for a specific interface. All prioritized interfaces are searched for default methods in the order of their specification. If no prioritized interface defines a default method of equivalent signature to the given instrumented method, any non-prioritized interface is searched for a suitable default method. If exactly one of those interfaces defines a suitable default method, this method is invoked. If no method or more than one method is identified as a suitable default method, an exception is thrown.

     

    When it comes to default methods, the Java programming language specifies stronger requirements for the legitimacy of invoking a default method than the Java runtime. The Java compiler requires a method to be the most specific method in its defining type's type hierarchy, i.e. the method must not be overridden by another interface or class type. Additionally, the method must be invokable from an interface type which is directly implemented by the instrumented type. The Java runtime only requires the second condition to be fulfilled which is why this implementation only checks the later condition, as well.
    • Field Detail

      • prioritizedInterfaces

        private final java.util.List<TypeDescription> prioritizedInterfaces
        A list of prioritized interfaces in the order in which a method should be attempted to be called.
    • Constructor Detail

      • DefaultMethodCall

        protected DefaultMethodCall​(java.util.List<TypeDescription> prioritizedInterfaces)
        Creates a new DefaultMethodCall implementation for a given list of prioritized interfaces.
        Parameters:
        prioritizedInterfaces - A list of prioritized interfaces in the order in which a method should be attempted to be called.
    • Method Detail

      • prioritize

        public static Implementation prioritize​(java.lang.Class<?>... prioritizedInterface)
        Creates a DefaultMethodCall implementation which searches the given list of interface types for a suitable default method in their order. If no such prioritized interface is suitable, because it is either not defined on the instrumented type or because it does not define a suitable default method, any remaining interface is searched for a suitable default method. If no or more than one method defines a suitable default method, an exception is thrown.
        Parameters:
        prioritizedInterface - A list of prioritized default method interfaces in their prioritization order.
        Returns:
        An implementation which calls an instrumented method's compatible default method that considers the given interfaces to be prioritized in their order.
      • prioritize

        public static Implementation prioritize​(java.lang.Iterable<? extends java.lang.Class<?>> prioritizedInterfaces)
        Creates a DefaultMethodCall implementation which searches the given list of interface types for a suitable default method in their order. If no such prioritized interface is suitable, because it is either not defined on the instrumented type or because it does not define a suitable default method, any remaining interface is searched for a suitable default method. If no or more than one method defines a suitable default method, an exception is thrown.
        Parameters:
        prioritizedInterfaces - A list of prioritized default method interfaces in their prioritization order.
        Returns:
        An implementation which calls an instrumented method's compatible default method that considers the given interfaces to be prioritized in their order.
      • prioritize

        public static Implementation prioritize​(TypeDescription... prioritizedInterface)
        Creates a DefaultMethodCall implementation which searches the given list of interface types for a suitable default method in their order. If no such prioritized interface is suitable, because it is either not defined on the instrumented type or because it does not define a suitable default method, any remaining interface is searched for a suitable default method. If no or more than one method defines a suitable default method, an exception is thrown.
        Parameters:
        prioritizedInterface - A list of prioritized default method interfaces in their prioritization order.
        Returns:
        An implementation which calls an instrumented method's compatible default method that considers the given interfaces to be prioritized in their order.
      • prioritize

        public static Implementation prioritize​(java.util.Collection<? extends TypeDescription> prioritizedInterfaces)
        Creates a DefaultMethodCall implementation which searches the given list of interface types for a suitable default method in their order. If no such prioritized interface is suitable, because it is either not defined on the instrumented type or because it does not define a suitable default method, any remaining interface is searched for a suitable default method. If no or more than one method defines a suitable default method, an exception is thrown.
        Parameters:
        prioritizedInterfaces - A collection of prioritized default method interfaces in their prioritization order.
        Returns:
        An implementation which calls an instrumented method's compatible default method that considers the given interfaces to be prioritized in their order.
      • unambiguousOnly

        public static Implementation unambiguousOnly()
        Creates a DefaultMethodCall implementation without prioritizing any interface. Instead, any interface that is defined for a given type is searched for a suitable default method. If exactly one interface defines a suitable default method, this method is invoked from the instrumented method. Otherwise, an exception is thrown.
        Returns:
        An implementation which calls an instrumented method's compatible default method if such a method is unambiguous.
      • appender

        public ByteCodeAppender appender​(Implementation.Target implementationTarget)
        Creates a byte code appender that determines the implementation of the instrumented type's methods.
        Specified by:
        appender in interface Implementation
        Parameters:
        implementationTarget - The target of the current implementation.
        Returns:
        A byte code appender for implementing methods delegated to this implementation. This byte code appender is also responsible for handling methods that were added by this implementation on the call to InstrumentedType.Prepareable.prepare(InstrumentedType).
      • filterRelevant

        private java.util.List<TypeDescription> filterRelevant​(TypeDescription typeDescription)
        Filters the relevant prioritized interfaces for a given type, i.e. finds the types that are directly declared on a given instrumented type.
        Parameters:
        typeDescription - The instrumented type for which the prioritized interfaces are to be filtered.
        Returns:
        A list of prioritized interfaces that are additionally implemented by the given type.