package examples.ejb.extensions.isModified;

import java.io.Serializable;
import java.rmi.RemoteException;
import java.rmi.Remote;
import javax.ejb.*;
import java.util.*;

/**
 * AccountBean is an EntityBean. This EJBean illustrates:
 * <ul>
 * <li> Container-managed JDBC persistence and transactions; 
 *      the code in this file never directly accesses the data storage.
 * <li> Application-defined exceptions.
 * </ul>
 *
 * @author Copyright (c) 1998 by WebLogic, Inc. All Rights Reserved.
 * @author Copyright (c) 1998-1999 by BEA WebXpress. All Rights Reserved.
 */
public class AccountBean implements EntityBean {
  final static boolean VERBOSE = true;

  // -----------------------------------------------------------------
  // private variables
  private transient EntityContext ctx;

  // -----------------------------------------------------------------
  // public container managed variables
  public            String        accountId; // also the primary Key
  public            double        balance;
  public            String        type; // "Checking"
  private transient boolean       isDirty; 
   
  // -----------------------------------------------------------------
  // EntityBean implementation
  
  /**
   * Returns whether the EJBean has been modified or not.
   * 
   * @return                  boolean isDirty
   */
  public boolean isModified() {
    if (VERBOSE)
      System.out.println ("isModified(): isDirty = " + (isDirty ? "true" : "false"));
    return isDirty;
  }


  /**
   * Sets the EJBean's modified flag.
   * 
   * @param flag              Modified Flag
   */
  public void setModified(boolean flag) {
    isDirty = flag;
    if (VERBOSE)
      System.out.println("setModified(): " + id() + (String) (flag ? ": requires saving" 
                         : ": saving not required"));
  }


  /**
   * Returns the Primary Key identifying this EJBean.
   * 
   * @return                  String Identification
   */
  private String id() {
    return "" + System.identityHashCode(this) + ", PK = " + 
      (String) ((ctx == null) ? "nullctx" 
                 : ((ctx.getPrimaryKey() == null ?
                   "null" : ctx.getPrimaryKey().toString()))) +
      "; isDirty = " + isDirty;

  }

  /**
   * This method is required by the EJB Specification,
   * but is not used by this example.
   * 
   */
  public void ejbActivate() {
    if (VERBOSE)
      System.out.println("ejbActivate(): " + id());
  }

  /**
   * This method is required by the EJB Specification,
   * but is not used by this example.
   * 
   */
  public void ejbPassivate() {
    if (VERBOSE)
      System.out.println("ejbPassivate(): " + id());
  }

  /**
   * Sets the EntityContext for the EJBean.
   * 
   * @param ctx               EntityContext 
   */
  public void setEntityContext(EntityContext ctx) {
    if (VERBOSE)
      System.out.println("setEntityContext(): " + id());
    this.ctx = ctx;
  }

  /**
   * Unsets the EntityContext for the EJBean.
   * 
   */
  public void unsetEntityContext() {
    if (VERBOSE)
      System.out.println("unsetEntityContext(): " + id());
    this.ctx = null;
  }

  /**
   * Sets the EJBean's modified flag to false.
   * 
   */
  public void ejbLoad() {
    if (VERBOSE)
      System.out.println("ejbLoad(): " + id());
    setModified(false); // to avoid writing
  }

  /**
   * Sets the EJBean's modified flag to false.
   * 
   */
  public void ejbStore() {
    if (VERBOSE)
      System.out.println("ejbStore(): " + id());
    setModified(false); // to avoid writing
  }

  /**
   * This method is required by the EJB Specification,
   * but is not used by this example.
   * 
   * @exception               javax.ejb.RemoveException
   *                          if the EJBean does not allow removing the EJBean
   */
  public void ejbRemove()
     throws RemoveException
  {
    if (VERBOSE)
      System.out.println("AccountBean.ejbRemove (" + id() + ")");
  }

  /**
   * This method corresponds to the create method in the home interface
   * "AccountHome.java". 
   * The parameter sets of the two methods are identical.  When the client calls
   * <code>AccountHome.create()</code>, the container (which in WebLogic EJB is
   * also the home) allocates an instance of this EJBean and
   * calls <code>AccountBean.ejbCreate()</code>.
   * <p>
   * For container-managed persistence, <code>ejbCreate()</code> returns 
   * a void, unlike the case of bean-managed
   * persistence, where it returns a primary key.
   *
   * @param accountID         String Account ID
   * @param initialBalance    double Initial Balance
   * @param type              String Account type
   * @exception               javax.ejb.CreateException
   *                          if there is a problem creating the bean
   */
  public void ejbCreate(String accountId, double initialBalance, String type) 
    throws CreateException
  {
    if (VERBOSE) 
      System.out.println("AccountBean.ejbCreate( id = " + System.identityHashCode(this) + ", PK = " +
                         accountId + ", " + "initial balance = $ " + initialBalance + 
                         ", type = " + type + ")");
    this.accountId = accountId;
    this.balance   = initialBalance;
    this.type      = type;
  }

  /**
   * This method is required by the EJB Specification,
   * but is not used by this example.
   *
   * @param accountID         String Account Identification
   * @param initialBalance    double Initial Balance 
   * @param type              String Account type
   */
  public void ejbPostCreate(String accountId, double initialBalance, String type)
  {
    if (VERBOSE)
      System.out.println("ejbPostCreate(): " + id());
  }


  // Application defined methods

  /**
   * Adds amount to balance.
   *
   * @param amount            double Amount
   * @return                  double balance 
   */
  public double deposit(double amount) {
    if (VERBOSE) 
      System.out.println("deposit(): Depositing $" + amount + " into '" + accountId + "'");
    balance += amount;
    setModified(true); // to force writing
    return balance;
  }

  /**
   * Subtracts amount from balance.
   *
   * @param amount            double Amount
   * @return                  double Balance 
   * @exception               ProcessingErrorException
   *                          if Amount &gt; Balance
   */
  public double withdraw(double amount)
       throws ProcessingErrorException
  {
    if (VERBOSE) 
      System.out.println("withdraw(): Withdrawing $" + amount + " from '" + accountId + "'");
    if (amount > balance) {
      throw new ProcessingErrorException("Request to withdraw $" + amount +
                                         "; is more than balance $" + balance +
                                         " in account " + accountId);
    }
    balance -= amount;
    setModified(true); // to force writing
    return balance;
  }

  /**
   * Returns current balance.
   *
   * @return                  double Balance 
   */
  public double balance() {
    if (VERBOSE) 
      System.out.println("balance(): balance $" + balance);
    return balance;
  }

  /**
   * Returns account type.
   *
   * @return                  String Type 
   */
  public String type() {
    return type;
  }
}