Table of Contents
In order to illustrate DPL usage, we provide a complete working example in this chapter. This example reads and writes inventory and vendor information for a mythical business. The application consists of the following classes:
Several classes used to encapsulate our application's data. See Vendor.java and Inventory.java.
A convenience class used to open and close our environment and entity store. See MyDbEnv.
A class that loads data into the store. See ExampleDatabasePut.java.
Finally, a class that reads data from the store. See ExampleInventoryRead.java.
The simplest class that our example wants to store contains vendor contact information. This class contains no secondary indices so all we have to do is identify it as an entity class and identify the field in the class used for the primary key.
                        In the following example, we identify the
                        vendor data member as containing the
                        primary key. This data member is meant to contain a
                        vendor's name. Because of the way we will use our
                        EntityStore, the value
                        provided for this data member must be unique within
                        the store or runtime errors will result.
                    
                        When used with the DPL, our
                        Vendor class appears as
                        follows. Notice that the @Entity
                        annotation appears immediately before the class
                        declaration, and the @PrimaryKey
                        annotation appears immediately before the
                        vendor data member declaration.
                    
package persist.gettingStarted;
import com.sleepycat.persist.model.Entity;
import com.sleepycat.persist.model.PrimaryKey;
@Entity
public class Vendor {
    private String address;
    private String bizPhoneNumber;
    private String city;
    private String repName;
    private String repPhoneNumber;
    private String state;
    // Primary key is the vendor's name
    // This assumes that the vendor's name is
    // unique in the database.
    @PrimaryKey
    private String vendor;
    private String zipcode;
    public void setRepName(String data) {
        repName = data;
    }
    public void setAddress(String data) {
        address = data;
    }
    public void setCity(String data) {
        city = data;
    }
    public void setState(String data) {
        state = data;
    }
    public void setZipcode(String data) {
        zipcode = data;
    }
    public void setBusinessPhoneNumber(String data) {
        bizPhoneNumber = data;
    }
    public void setRepPhoneNumber(String data) {
        repPhoneNumber = data;
    }
    public void setVendorName(String data) {
        vendor = data;
    }
    public String getRepName() {
        return repName;
    }
    public String getAddress() {
        return address;
    }
    public String getCity() {
        return city;
    }
    public String getState() {
        return state;
    }
    public String getZipcode() {
        return zipcode;
    }
    public String getBusinessPhoneNumber() {
        return bizPhoneNumber;
    }
    public String getRepPhoneNumber() {
        return repPhoneNumber;
    }
} 
        
                            For this class, the vendor value is set for an individual
                            Vendor class object by
                            the setVendorName()
                            method. If our example code fails to set this
                            value before storing the object, the data
                            member used to store the primary key is set to a
                            null value. This would result in a runtime
                            error.