manufacturehelper.java

ORACLE AQ sample 演示的如何出列

package oracle.otnsamples.AQ.Helper;

/**
 * @author  Anupama
 * @version 1.0
 *
 * Development Environment        :  Oracle9i JDeveloper
 * Name of the Application        :  ManufactureHelper.java
 * Creation/Modification History  :
 *
 *    Anupama      27-Jan-2002      Created
 *
 */

// Util imports
import java.util.Hashtable;
import java.util.Vector;

// Other imports
import oracle.otnsamples.AQ.DataBase.DBConnect;

/**
 * This class is called for all the operations done by a Manufacturer.
 * Whether the manufacturer wants to add, delete, update products
 * from his database, all the requests go through this file.
 * Every method in this class corresponds to a request from the manufacturer.
 * This class generates the query required for any of the operations to
 * be done on the database.
 */
public class ManufactureHelper{
  /**
   * Empty Constructor
   */
  public ManufactureHelper() {
  }

  /**
   * This method is called once when the manufacturer successfully logs
   * in to the database. The basic functionality of this method
   * is to display all the products that are available with the manufacturer.
   * It constructors a query to retrieve all the products from the database
   * and sends it to DBConnect. It returns a Hash table which contains information
   * about the products present with the manufacturer. The Vector returned
   * by DBConnect is converted into Hash table. Product ID is used as key in
   * the Hash table.
   *
   * @exception Exception Incase of some error or unreported Exception
   * @param p_user Type of the user
   * @return Contains all the products which the manufacturer has in the
   *      database.
   * @see DBConnect.java
   */
  public static Hashtable displayProducts(String p_user) throws Exception {
    // Get DBConnect Instance to execute query
    DBConnect dbInstance = DBConnect.getInstance();

    // Construct the query
    String query = new StringBuffer().append("SELECT product_id, ")
                    .append("INITCAP(product_name), product_desc,")
                     .append(" manufacturer_id, price, category_desc, ")
                      .append("quantity_on_hand FROM product_master ")
                       .append("ORDER BY LOWER(product_name)").toString();

    // Execute the query using the instance. The Vector retrieved is sent to the
    // method and converted into a hash table.
    Hashtable productHash = storePrdsInHash(dbInstance.executeQuery(query, p_user));
    return productHash;
  }

  /**
   * This method is called once when the manufacturer wants to add a product
   * into the database. The basic functionality of this method
   * is to retrieve the product ID, construct a query to add the product
   * into the database using the product details sent and send it to DBConnect.
   * Then call the method in EnqueuePrdHelper which adds the product to queue
   * so that the Retail manager will know about the change occurred through message
   * propagation. The product details are then added to the Hash of product
   * list and returned.
   *
   * @exception Exception Incase of some error or unreported Exception
   * @param p_user Type of the user
   * @param p_productList List of all the products the manufacturer has
   * @param p_addedProductInfo Details of the product to be added
   * @return Contains details of all the products present with the
   *      manufacturer along with the one added recently
   * @see DBConnect.java
   * @see Product.java
   * @see EnqueuePrdHelper.java
   */
  public static Hashtable addProduct(String p_user, Hashtable p_productList,
                          Product p_addedProductInfo) throws Exception {
    // Get DBConnect Instance to execute query
    DBConnect dbInstance = DBConnect.getInstance();

    // Get the next product id from the sequence present in the database.
    p_addedProductInfo.setProductID(getProductId(p_user));
  
    
    // If the manufacturer Id is not present (this is in case when no product
    // is present in the table and the first product is being added) then
    // retrieve the manufacturer ID from database.
    if(p_addedProductInfo.getManufactureID()==null){
     p_addedProductInfo.setManufactureID(getManufacturerId(p_user));
    }
    
    // Construct the query
    String query = new StringBuffer().append("INSERT INTO Product_Master ")
                    .append("(product_id,product_name,product_desc,manufacturer_id,")
                    .append("price,category_desc,quantity_on_hand) VALUES('")
                    .append(p_addedProductInfo.getProductID()).append("','")
                    .append(p_addedProductInfo.getProductName()).append("','")
                    .append(p_addedProductInfo.getProductDesc()).append("','")
                    .append(p_addedProductInfo.getManufactureID()).append("','")
                    .append(p_addedProductInfo.getProductPrice()).append("','")
                    .append(p_addedProductInfo.getCategoryDesc()).append("','")
                    .append(p_addedProductInfo.getQuantityOnHand())
                    .append("')").toString();

    // Execute the query using the DBConnect instance retrieved.
    dbInstance.executeUpdate(query, p_user);

    // Add the product details into Queue.
    EnqueuePrdHelper.addPrdToQueue(p_addedProductInfo, p_user, "ADD");

    // Add the product details into the list of product present in hash table.
    p_productList.put(p_addedProductInfo.getProductID(), p_addedProductInfo);

    return p_productList;
  }


  /**
   * This method is called when the manufacturer wants to update the details
   * of a product. The basic functionality of this method is construct a
   * query to update the product whose details are sent in the database
   * using the get methods present in Product.java and send it to DBConnect.
   * Then call the method in EnqueuePrdHelper which adds the product to queue
   * so that the Retail manager will know about the change occurred through message
   * propagation. The product details are then added to the Hash of product
   * list and returned.
   *
   * @exception Exception Incase of some error or unreported Exception
   * @param p_user Type of the user
   * @param p_productList List of all the products the manufacturer has
   * @param p_updatedProductInfo Details of the product to be updated
   * @return Contains details of all the products present with the
   *     manufacturer
   * @see DBConnect.java
   * @see EnqueuePrdHelper.java
   * @see Product.java
   */
  public static Hashtable updateProduct(String p_user, Hashtable p_productList,
                                Product p_updatedProductInfo) throws Exception{
    // Get DBConnect Instance to execute query
    DBConnect dbInstance = DBConnect.getInstance();

    // Construct the query
    String query=new StringBuffer().append("UPDATE PRODUCT_MASTER SET product_desc='")
                   .append(p_updatedProductInfo.getProductDesc())
                   .append("', price='")
                   .append(p_updatedProductInfo.getProductPrice())
                   .append("', category_desc='")
                   .append(p_updatedProductInfo.getCategoryDesc()).append("',")
                   .append(" quantity_on_hand='")
                   .append(p_updatedProductInfo.getQuantityOnHand())
                   .append("' WHERE ").append("product_id = '")
                   .append(p_updatedProductInfo.getProductID())
                   .append("' AND manufacturer_id ='")
                   .append(p_updatedProductInfo.getManufactureID())
                   .append("'").toString();

    // Execute the query using the DBConnect instance retrieved.
    dbInstance.executeUpdate(query, p_user);

    // Add the product details into Queue.
    EnqueuePrdHelper.addPrdToQueue(p_updatedProductInfo, p_user, "UPDATE");

    // Add the product details into product list. The details of the product
    // which are already present are overwritten.