reflection

// Reflection

 

public class Visitor {

    public void visit(final Object object) {

        Method objMethod1 = null;

        // Class objClass1 = Integer.TYPE;

        // Class objClass1 = Element.class;

        Class objClass1 = object.getClass();

        String className = object.getClass().getName();

        String methodName = "accept" + className.substring(className.lastIndexOf('.') + 1);

        System.out.println("className:" + className + " methodName:" + methodName);

 

        try {

            // get method

            objMethod1 = objClass1.getMethod(methodName, new Class[] {this.getClass()});

            System.out.println("objMethod:" + objMethod1);

        } catch

        // get all methods

        Method[] methods = objClass1.getMethods();

        for (int i = 0; i < methods.length; i++) {

            System.out.println("methods:" + methods[i]);

        }

        try {

            // invoke method

            objMethod1.invoke(object, new Object[] {this});

        } catch

 

        Class[] cls = new Class[] {String.class};

        try {

            // newInstance, getConstructor

            System.out.println(String.class.getConstructor(cls).newInstance(new Object[] {"abc"}));

        } catch

 

        try {

            // newInstance, forName

            Class.forName(className).newInstance();

        } catch

 

        try {

            // newInstance

            Element.class.newInstance();

        } catch

    }

}

 

public class Element {

    public void accept(final Visitor visitor) {

        visitor.visit(this);

    }

    public void acceptElement(final Visitor visitor) {

        System.out.println("acceptElement run!");

    }

    public Element() {

        System.out.println("new Element!");

    }

}

 

public class Client {

    public static void main(final String[] args) {

        Visitor visitor = new Visitor();

        Element element = new Element();

        element.accept(visitor);

    }

}