// The MIT License (MIT)

//

// Copyright (c) 2018 Robert C. Seacord

//

// Permission is hereby granted, free of charge, to any person obtaining a copy

// of this software and associated documentation files (the "Software"), to deal

// in the Software without restriction, including without limitation the rights

// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell

// copies of the Software, and to permit persons to whom the Software is

// furnished to do so, subject to the following conditions:

//

// The above copyright notice and this permission notice shall be included in all

// copies or substantial portions of the Software.

//

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR

// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE

// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,

// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE

// SOFTWARE.

package OBJ03J;

import java.util.ArrayList;

import java.util.Collections;

import java.util.List;

class listUtility {

// Raw object added to parameterized list

private static void addToList(List list, Object obj) {

list.add(obj); // Unchecked warning

}

// Correctly typed object added to parameterized list.

/*

private static void addToList(List<String> list, String obj) {

list.add(obj); // Unchecked warning }

}

*/

public static void main(String[] args) {

List<String> list = new ArrayList<>();

// The call to addToList(list, 42) succeeds in adding an integer to

// list, although it is of type List<String>.

addToList(list, 42);

// This Java runtime does not throw a ClassCastException until the value

// is read and has an invalid type (an int rather than a String).

try {

System.out.println(list.get(0)); // Throws ClassCastException

}

catch (ClassCastException cce) {

cce.printStackTrace();

}

// If the addToList() method is legacy code that cannot be changed,

// create a checked list view y using the Collections.checkedList() method.

// This method returns a wrapper collection that performs runtime type checking in

// its implementation of the add() method before delegating to the

// back-end List<String>.

List<String> backlist = new ArrayList<>();

List<String> checkedList = Collections.checkedList(backlist, String.class);

addToList(checkedList, 42);

System.out.println(list.get(0));

}

}