We start by importing two additional classes needed to support secondary databases. We also add a global variable to use as a handle for our secondary database.

// File MyDbs.java
package db.GettingStarted;

import java.io.FileNotFoundException;

import com.sleepycat.bind.serial.StoredClassCatalog;
import com.sleepycat.bind.tuple.TupleBinding;
import com.sleepycat.db.Database;
import com.sleepycat.db.DatabaseConfig;
import com.sleepycat.db.DatabaseException;
import com.sleepycat.db.DatabaseType;
import com.sleepycat.db.SecondaryConfig;
import com.sleepycat.db.SecondaryDatabase;

public class MyDbs {

    // The databases that our application uses
    private Database vendorDb = null;
    private Database inventoryDb = null;
    private Database classCatalogDb = null;
    private SecondaryDatabase itemNameIndexDb = null;

    private String vendordb = "VendorDB.db";
    private String inventorydb = "InventoryDB.db";
    private String classcatalogdb = "ClassCatalogDB.db";
    private String itemnameindexdb = "ItemNameIndexDB.db";

    // Needed for object serialization
    private StoredClassCatalog classCatalog;

    // Our constructor does nothing
    public MyDbs() {} 

Next we update the MyDbs.setup() method to open the secondary database. As a part of this, we have to pass an ItemNameKeyCreator object on the call to open the secondary database. Also, in order to instantiate ItemNameKeyCreator, we need an InventoryBinding object (we described this class in InventoryBinding.java). We do all this work together inside of MyDbs.setup().

    public void setup(String databasesHome)
        throws DatabaseException {
        DatabaseConfig myDbConfig = new DatabaseConfig();
        SecondaryConfig mySecConfig = new SecondaryConfig();

        myDbConfig.setErrorStream(System.err);
        mySecConfig.setErrorStream(System.err);
        myDbConfig.setErrorPrefix("MyDbs");
        mySecConfig.setErrorPrefix("MyDbs");
        myDbConfig.setType(DatabaseType.BTREE);
        mySecConfig.setType(DatabaseType.BTREE);
        myDbConfig.setAllowCreate(true);
        mySecConfig.setAllowCreate(true);

        // Now open, or create and open, our databases
        // Open the vendors and inventory databases
        try {
            vendordb = databasesHome + "/" + vendordb;
            vendorDb = new Database(vendordb,
                                    null,
                                    myDbConfig);

            inventorydb = databasesHome + "/" + inventorydb;
            inventoryDb = new Database(inventorydb,
                                        null,
                                        myDbConfig);

            // Open the class catalog db. This is used to
            // optimize class serialization.
            classcatalogdb = databasesHome + "/" + classcatalogdb;
            classCatalogDb = new Database(classcatalogdb,
                                          null,
                                          myDbConfig);
        } catch(FileNotFoundException fnfe) {
            System.err.println("MyDbs: " + fnfe.toString());
            System.exit(-1);
        }

        // Create our class catalog
        classCatalog = new StoredClassCatalog(classCatalogDb);

        // Need a tuple binding for the Inventory class.
        // We use the InventoryBinding class
        // that we implemented for this purpose.
        TupleBinding inventoryBinding = new InventoryBinding();

        // Open the secondary database. We use this to create a
        // secondary index for the inventory database

        // We want to maintain an index for the inventory entries based
        // on the item name. So, instantiate the appropriate key creator
        // and open a secondary database.
        ItemNameKeyCreator keyCreator =
            new ItemNameKeyCreator(new InventoryBinding());

        // Set up additional secondary properties
        // Need to allow duplicates for our secondary database
        mySecConfig.setSortedDuplicates(true);
        mySecConfig.setAllowPopulate(true); // Allow autopopulate
        mySecConfig.setKeyCreator(keyCreator);
        // Now open it
        try {
            itemnameindexdb = databasesHome + "/" + itemnameindexdb;
            itemNameIndexDb = new SecondaryDatabase(itemnameindexdb,
                                                    null,
                                                    inventoryDb,
                                                    mySecConfig);
        } catch(FileNotFoundException fnfe) {
            System.err.println("MyDbs: " + fnfe.toString());
            System.exit(-1);
        }
    }
    

Next we need an additional getter method for returning the secondary database.

    public SecondaryDatabase getNameIndexDB() {
        return itemNameIndexDb;
    } 

Finally, we need to update the MyDbs.close() method to close the new secondary database. We want to make sure that the secondary is closed before the primaries. While this is not necessary for this example because our closes are single-threaded, it is still a good habit to adopt.

    public void close() {
        try {
            if (itemNameIndexDb != null) {
                itemNameIndexDb.close();
            }

            if (vendorDb != null) {
                vendorDb.close();
            }

            if (inventoryDb != null) {
                inventoryDb.close();
            }

            if (classCatalogDb != null) {
                classCatalogDb.close();
            }

        } catch(DatabaseException dbe) {
            System.err.println("Error closing MyDbs: " +
                                dbe.toString());
            System.exit(-1);
        }
    }
} 

That completes our update to MyDbs. You can find the complete class implementation in:

DB_INSTALL/examples/java/db/GettingStarted

where DB_INSTALL is the location where you placed your DB distribution.

First we need to import an additional class in order to use the secondary cursor:

package db.GettingStarted;

import java.io.IOException;

import com.sleepycat.bind.EntryBinding;
import com.sleepycat.bind.serial.SerialBinding;
import com.sleepycat.bind.tuple.TupleBinding;
import com.sleepycat.db.Cursor;
import com.sleepycat.db.DatabaseEntry;
import com.sleepycat.db.DatabaseException;
import com.sleepycat.db.LockMode;
import com.sleepycat.db.OperationStatus;
import com.sleepycat.db.SecondaryCursor; 

Next we add a single global variable:

    public class ExampleDatabaseRead {

    private static String myDbsPath = "./";

    // Encapsulates the database environment and databases.
    private static MyDbs myDbs = new MyDbs();

    private static TupleBinding inventoryBinding;
    private static EntryBinding vendorBinding;

    // The item to locate if the -s switch is used
    private static String locateItem; 

Next we update ExampleDatabaseRead.run() to check to see if the locateItem global variable has a value. If it does, then we show just those records related to the item name passed on the -s switch.

    private void run(String args[]) 
        throws DatabaseException {
        // Parse the arguments list
        parseArgs(args);

        myDbs.setup(myDbsPath);

        // Setup our bindings.
        inventoryBinding = new InventoryBinding();
        vendorBinding =
             new SerialBinding(myDbs.getClassCatalog(),
                               Vendor.class);

            if (locateItem != null) {
                showItem();
            } else {
                showAllInventory();
            }
    } 

Finally, we need to implement ExampleDatabaseRead.showItem(). This is a fairly simple method that opens a secondary cursor, and then displays every primary record that is related to the secondary key identified by the locateItem global variable.

    private void showItem() throws DatabaseException {
        SecondaryCursor secCursor = null;
        try {
            // searchKey is the key that we want to find in the
            // secondary db.
            DatabaseEntry searchKey =
                new DatabaseEntry(locateItem.getBytes("UTF-8"));

            // foundKey and foundData are populated from the primary
            // entry that is associated with the secondary db key.
            DatabaseEntry foundKey = new DatabaseEntry();
            DatabaseEntry foundData = new DatabaseEntry();

            // open a secondary cursor
            secCursor =
                myDbs.getNameIndexDB().openSecondaryCursor(null, null);

            // Search for the secondary database entry.
            OperationStatus retVal =
                secCursor.getSearchKey(searchKey, foundKey,
                    foundData, LockMode.DEFAULT);

            // Display the entry, if one is found. Repeat until no more
            // secondary duplicate entries are found
            while(retVal == OperationStatus.SUCCESS) {
                Inventory theInventory =
                    (Inventory)inventoryBinding.entryToObject(foundData);
                displayInventoryRecord(foundKey, theInventory);
                retVal = secCursor.getNextDup(searchKey, foundKey,
                    foundData, LockMode.DEFAULT);
            }
        } catch (Exception e) {
            System.err.println("Error on inventory secondary cursor:");
            System.err.println(e.toString());
            e.printStackTrace();
        } finally {
            if (secCursor != null) {
                secCursor.close();
            }
        }

    }

The only other thing left to do is to update ExampleDatabaseRead.parseArgs() to support the -s command line switch. To see how this is done, see ExampleDatabaseRead.java in:

DB_INSTALL/examples/java/db/GettingStarted

where DB_INSTALL is the location where you placed your DB distribution.