Module java.base
Package java.lang.invoke

Class SerializedLambda

  • All Implemented Interfaces:
    Serializable
    public final class SerializedLambda
extends Object
implements Serializable
    Serialized form of a lambda expression. The properties of this class represent the information that is present at the lambda factory site, including static metafactory arguments such as the identity of the primary functional interface method and the identity of the implementation method, as well as dynamic metafactory arguments such as values captured from the lexical scope at the time of lambda capture.

    Implementors of serializable lambdas, such as compilers or language runtime libraries, are expected to ensure that instances deserialize properly. One means to do so is to ensure that the writeReplace method returns an instance of SerializedLambda, rather than allowing default serialization to proceed.

    SerializedLambda has a readResolve method that looks for a (possibly private) static method called $deserializeLambda$(SerializedLambda) in the capturing class, invokes that with itself as the first argument, and returns the result. Lambda classes implementing $deserializeLambda$ are responsible for validating that the properties of the SerializedLambda are consistent with a lambda actually captured by that class.

    The identity of a function object produced by deserializing the serialized form is unpredictable, and therefore identity-sensitive operations (such as reference equality, object locking, and System.identityHashCode() may produce different results in different implementations, or even upon different deserializations in the same implementation.

    Since:
    1.8
    See Also:
    LambdaMetafactory, Serialized Form

    • Constructor Detail

      • SerializedLambda

        public SerializedLambda​(Class<?> capturingClass,
                        String functionalInterfaceClass,
                        String functionalInterfaceMethodName,
                        String functionalInterfaceMethodSignature,
                        int implMethodKind,
                        String implClass,
                        String implMethodName,
                        String implMethodSignature,
                        String instantiatedMethodType,
                        Object[] capturedArgs)
        Create a SerializedLambda from the low-level information present at the lambda factory site.
        Parameters:
        capturingClass - The class in which the lambda expression appears
        functionalInterfaceClass - Name, in slash-delimited form, of static type of the returned lambda object
        functionalInterfaceMethodName - Name of the functional interface method for the present at the lambda factory site
        functionalInterfaceMethodSignature - Signature of the functional interface method present at the lambda factory site
        implMethodKind - Method handle kind for the implementation method
        implClass - Name, in slash-delimited form, for the class holding the implementation method
        implMethodName - Name of the implementation method
        implMethodSignature - Signature of the implementation method
        instantiatedMethodType - The signature of the primary functional interface method after type variables are substituted with their instantiation from the capture site
        capturedArgs - The dynamic arguments to the lambda factory site, which represent variables captured by the lambda

    • Method Detail

      • getCapturingClass

        public String getCapturingClass()
        Get the name of the class that captured this lambda.
        Returns:
        the name of the class that captured this lambda

      • getFunctionalInterfaceClass

        public String getFunctionalInterfaceClass()
        Get the name of the invoked type to which this lambda has been converted
        Returns:
        the name of the functional interface class to which this lambda has been converted

      • getFunctionalInterfaceMethodName

        public String getFunctionalInterfaceMethodName()
        Get the name of the primary method for the functional interface to which this lambda has been converted.
        Returns:
        the name of the primary methods of the functional interface

      • getFunctionalInterfaceMethodSignature

        public String getFunctionalInterfaceMethodSignature()
        Get the signature of the primary method for the functional interface to which this lambda has been converted.
        Returns:
        the signature of the primary method of the functional interface

      • getImplClass

        public String getImplClass()
        Get the name of the class containing the implementation method.
        Returns:
        the name of the class containing the implementation method

      • getImplMethodName

        public String getImplMethodName()
        Get the name of the implementation method.
        Returns:
        the name of the implementation method

      • getImplMethodSignature

        public String getImplMethodSignature()
        Get the signature of the implementation method.
        Returns:
        the signature of the implementation method

      • getImplMethodKind

        public int getImplMethodKind()
        Get the method handle kind (see MethodHandleInfo) of the implementation method.
        Returns:
        the method handle kind of the implementation method

      • getInstantiatedMethodType

        public final String getInstantiatedMethodType()
        Get the signature of the primary functional interface method after type variables are substituted with their instantiation from the capture site.
        Returns:
        the signature of the primary functional interface method after type variable processing

      • getCapturedArgCount

        public int getCapturedArgCount()
        Get the count of dynamic arguments to the lambda capture site.
        Returns:
        the count of dynamic arguments to the lambda capture site

      • getCapturedArg

        public Object getCapturedArg​(int i)
        Get a dynamic argument to the lambda capture site.
        Parameters:
        i - the argument to capture
        Returns:
        a dynamic argument to the lambda capture site