devxlogo

Write a Primary Key Class in CMP EJB

Write a Primary Key Class in CMP EJB

In the following example, the PurchaseOrderKey class implements a composite key for the PurchaseOrderEJB entity bean. The key is composed of two fields, productModel and vendorId, whose names must match two of the persistent fields in the entity bean class.

public class PurchaseOrderKey implements java.io.Serializable {    public String productModel;    public String vendorId;    public PurchaseOrderKey() { };    public String getProductModel() {        return productModel;    }    public String getVendorId() {        return vendorId;    }    public boolean equals(Object other) {        if (other instanceof PurchaseOrderKey) {           return (productModel.equals(               ((PurchaseOrderKey)other).productModel) &&               vendorId.equals(               ((PurchaseOrderKey)other).vendorId));        }        return false;    }    public int hashCode() {        return productModel.concat(vendorId).hashCode();    }}
devxblackblue

About Our Editorial Process

At DevX, we’re dedicated to tech entrepreneurship. Our team closely follows industry shifts, new products, AI breakthroughs, technology trends, and funding announcements. Articles undergo thorough editing to ensure accuracy and clarity, reflecting DevX’s style and supporting entrepreneurs in the tech sphere.

See our full editorial policy.

About Our Journalist