How to compare objects by property

Question

I have an object called Product and I want to check if a user-entered string matches the name of one of the Products.

I tried the code below but it doesn't work.

Product  laptop = new Product(1, "Laptop", "Type", 1350.25, "black");
Product  mouse = new Product(2, "Mouse", "Type", 50.50, "black");

String check = new String("laptop");

if (check.equals(instanceof Product))  
{
    System.out.println("Yes it is.");
}
    else
{
    System.out.println("No, it is not.");
}

The purpose of `instanceOf` is to check if a instance is of a specified class. — Jens, Jun 03 '18 at 10:37
Create a collection of all `Product` instances, iterate over that and for each element check wether or not the `name` (or whatever) contains the search term. — luk2302, Jun 03 '18 at 10:38
Your examples show that you lack the fundamentals or programming. I would recommend you find a good tutorial which comes with homework examples and work through that tutorial (while completing **every** example faithfully). — Neuron, Jun 03 '18 at 12:49

score 0 · Accepted Answer · answered Jun 03 '18 at 14:08

I assume you have a name variable in your Product class. So what you would want to do is compare the name variable to the String. Something like this:

private String name;
Product  laptop = new Product(1, "Laptop", "Type", 1350.25, "black");
Product  mouse = new Product(2, "Mouse", "Type", 50.50, "black");

String check = new String("laptop");
if(check.equals(laptop.getName()) {
    System.out.println("Match!");
} else {
    System.out.println("No match...");
}

Here's a good SO discussion about the proper use of instanceof:

What is the 'instanceof' operator used for in Java?

How to compare objects by property

1 Answers1