Groovy In Action 笔记 (8) -- MOP

/**
 * @author ：ZackZhou
 * @date ：Created in 2020/10/9 2:31 PM
 * @description ：
 * All classes that are compiled by Groovy implement the GroovyObject interface
 * Again, you’re free to implement any such methods in your Groovy class to your liking.
 * If you don’t, then the Groovy compiler will insert a default implementation for you.
 * This default implementation is the same as if you’d inherit from GroovyObjectSupport,
 * which basically relays all calls to the metaclass.
 *
 * public abstract class GroovyObjectSupport implements GroovyObject {
 * public Object invokeMethod(String name, Object args) {
 * return getMetaClass().invokeMethod(this, name, args);
 * }
 * public Object getProperty(String property) {
 * return getMetaClass().getProperty(this, property);
 * }
 * public void setProperty(String property, Object newValue) {
 * getMetaClass().setProperty(this, property, newValue);* }
 * // more here...
 * }
 *
 * As soon as a class implements GroovyObject, the following rules apply:
 * ■ Every access to a property calls the getProperty() method.6
 * ■ Every modification of a property calls the setProperty() method.
 * ■ Every call to an unknown method calls invokeMethod(). If the method is known,
 * invokeMethod() is only called if the class implements GroovyObject and the
 * marker interface GroovyInterceptable.
 *
 *
 * @modified By：
 * @version:
 */

// Groovy中提供的非JDK内置的方法，是通过  org.codehaus.groovy.runtime.DefaultGroovyMethods 这个类实现的
String myStr = ""
myStr.metaClass
println(myStr)

/*
// MOP pseudo code
def mopInvoke(Object obj, String method, Object args) {
    if (obj instanceof GroovyObject) {
        return groovyObjectInvoke(obj, method, args)
    }
    registry.getMetaClass(obj.class).invokeMethod(obj, method, args)
}

def groovyObjectInvoke(Object obj, String method, Object args){
    if (obj instanceof GroovyInterceptable) {
        return obj.metaClass.invokeMethod(method, args)
    }
    if (! obj.metaClass.respondsTo(method, args)) {
        return obj.metaClass.invokeMethod(method, args)
    }
    obj.metaClass.invokeMethod(obj, method, args)
}

// Default meta class pseudo code
def invokeMethod(Object obj, String method, Object args) {
    if (obj.metaClass.respondsTo(method, args)) {
        return methodCall(obj, method, args)
    }
    if (methodMissingAvailable(obj)) {
        return obj.metaClass.methodMissing(method, args)
    }
    throw new MissingMethodException()
}
*/