Class CachedReturnPlugin

  • All Implemented Interfaces:
    java.io.Closeable, java.lang.AutoCloseable, Plugin, Plugin.Factory, ElementMatcher<TypeDescription>

    @Enhance
    public class CachedReturnPlugin
    extends Plugin.ForElementMatcher
    implements Plugin.Factory
    A plugin that caches the return value of a method in a synthetic field. The caching mechanism is not thread-safe but can be used in a concurrent setup if the cached value is frozen, i.e. only defines final fields. In this context, it is possible that the method is executed multiple times by different threads but at the same time, this approach avoids a volatile field declaration. For methods with a primitive return type, the type's default value is used to indicate that a method was not yet invoked. For methods that return a reference type, null is used as an indicator. If a method returns such a value, this mechanism will not work. This plugin does not need to be closed.
    • Field Detail

      • NAME_INFIX

        private static final java.lang.String NAME_INFIX
        An infix between a field and the random suffix if no field name is chosen.
        See Also:
        Constant Field Values
      • ADVICE_INFIX

        private static final java.lang.String ADVICE_INFIX
        The infix symbol for advice classes.
        See Also:
        Constant Field Values
      • classFileLocator

        private final ClassFileLocator classFileLocator
        The class file locator to use.
      • adviceByType

        @ValueHandling(IGNORE)
        private final java.util.Map<TypeDescription,​TypeDescription> adviceByType
        A map of advice types mapped by their argument type. All advice types are precompiled using Java 6 to allow for releasing Byte Buddy with a Java 5 byte code level where compiled classes do not contain stack map frames. Byte Buddy filters stack map frames when applying advice in newer version but it cannot add stack map frames without explicit frame computation which is expensive which is why precompilation was used. To avoid loading Java classes in incompatible versions, all advice types are resolved using a type pool.
    • Constructor Detail

      • CachedReturnPlugin

        public CachedReturnPlugin()
        Creates a plugin for caching method return values.
    • Method Detail

      • make

        public Plugin make()
        Returns a plugin that can be used for a transformation and which is subsequently closed.
        Specified by:
        make in interface Plugin.Factory
        Returns:
        The plugin to use for type transformations.
      • apply

        public DynamicType.Builder<?> apply​(DynamicType.Builder<?> builder,
                                            TypeDescription typeDescription,
                                            ClassFileLocator classFileLocator)
        Applies this plugin.
        Specified by:
        apply in interface Plugin
        Parameters:
        builder - The builder to use as a basis for the applied transformation.
        typeDescription - The type being transformed.
        classFileLocator - A class file locator that can locate other types in the scope of the project.
        Returns:
        The supplied builder with additional transformations registered.
      • close

        public void close()
        Specified by:
        close in interface java.lang.AutoCloseable
        Specified by:
        close in interface java.io.Closeable