Byte Buddy可以通过使用EnumDefinition来定义具有抽象方法的枚举,并将抽象方法的实现委托给枚举值。下面是一个示例:
Class> dynamicEnum = new ByteBuddy()
.makeEnumeration("MyEnum")
.withModifiers(Modifier.PUBLIC)
.withValues("VALUE_1", "VALUE_2")
.defineMethod("abstractMethod", String.class, Modifier.ABSTRACT | Modifier.PUBLIC)
.make()
.load(getClass().getClassLoader())
.getLoaded();
Enum> value1 = (Enum>) dynamicEnum.getDeclaredField("VALUE_1").get(null);
Enum> value2 = (Enum>) dynamicEnum.getDeclaredField("VALUE_2").get(null);
Class extends Enum> enumClass = (Class extends Enum>) dynamicEnum;
Class> anonymousType = new ByteBuddy()
.subclass(Object.class)
.implement(enumClass, TypeDescription.Generic.Builder.parameterizedType(enumClass))
.method(not(isDeclaredBy(Object.class)))
.intercept(MethodDelegation.toField("delegate"))
.make()
.load(getClass().getClassLoader(), ClassLoadingStrategy.Default.INJECTION)
.getLoaded();
Object delegate = new ByteBuddy()
.subclass(Object.class)
.implement(enumClass.getDeclaredMethod("abstractMethod").getReturnType())
.name("MyDelegate")
.method(ElementMatchers.isDeclaredBy(enumClass))
.intercept(FixedValue.value("Hello world"))
.make()
.load(getClass().getClassLoader(), ClassLoadingStrategy.Default.WRAPPER)
.getLoaded()
.newInstance();
Field delegateField = anonymousType.getDeclaredField("delegate");
delegateField.setAccessible(true);
delegateField.set(null, delegate);
Enum> myEnum = (Enum>) anonymousType.getEnumConstants()[0];
myEnum.name(); // "VALUE_1"
myEnum.ordinal(); // 0
myEnum.getClass(); // class MyEnum
myEnum.toString(); // "VALUE_1"
myEnum.getDeclaredMethod("abstractMethod").invoke(myEnum); // "Hello world"
上述代码通过使用Byte Buddy定义了一个名为“MyEnum”的枚举,该枚举具