How to initialize Java Collection List a Map inside

Question

@Entity

public class SalesT {

    @Id
    @GeneratedValue
    private int id;

    @OneToOne
    private Customer customer;

    @OneToMany(targetEntity = Product.class)
    private List< Map<Product,Integer> > listProduct;// I want to intialize this

    public SalesT() {
    }

    public SalesT(Customer customer, List<Map<Product, Integer>> product) {
        this.customer = customer;
        this.listProduct = product;
    }
}

I want to Initialize List< Map < Product,Integer>> listProduct attribute of the SalesT Class, How do I initialize it?. I tried Like this

List<Map <Product, Integer>> listProduct = new ArrayList <HashMap <Product, Integer>>();

but it is not working.

Thank you.

TheKojuEffect · Accepted Answer · 2014-05-18 16:50:40Z

9

If you're using JDK 7, you can simply do,

listProduct = new ArrayList<>();

If JDK < 7,

listProduct = new ArrayList<Map<Product, Integer>>();

You can add maps to above list as follows.

Map<Product,Integer> productMap = new HashMap<Product, Integer>();
productMap.put(new Product(), 1);
productMap.put(new Product(), 2);

listProduct.add(productMap);

edited May 18, 2014 at 16:50

answered May 18, 2014 at 16:40

TheKojuEffect

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Comments

Maurice Perry · Accepted Answer · 2014-05-18 16:42:19Z

1

How about:

private List< Map<Product,Integer> > listProduct
            = new ArrayList<Map<Product,Integer>>();

answered May 18, 2014 at 16:42

Maurice Perry

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Comments

Aniket Thakur · Accepted Answer · 2014-05-18 16:42:43Z

0

You can simply do

List< Map<Product,Integer> > listProduct = new ArrayList<Map<Product,Integer>>();

answered May 18, 2014 at 16:42

Aniket Thakur

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