productbean.java

为大家提供了《精通EJB》（第三版)一书的源代码

package examples.cmp;

import javax.ejb.*;

/**
 * Entity Bean which demonstrates Container-Managed persistence.
 *
 * This is a product that's persistent.  It has an ID #, a name,
 * a description, and a base price.
 */
public abstract class ProductBean 
    implements EntityBean 
{
    protected EntityContext ctx;
    
    public ProductBean() {
    }

    //----------------------------------------------------------------
    // Begin abstract get/set methods
    //----------------------------------------------------------------
    
    public abstract String getName();
    public abstract void setName(String name);
    public abstract String getDescription();
    public abstract void setDescription(String description);	
    public abstract double getBasePrice();	
    public abstract void setBasePrice(double price);	
    public abstract String getProductID();
    public abstract void setProductID(String productID);
    
    //----------------------------------------------------------------
    // End abstract get/set methods
    //----------------------------------------------------------------
    
    //----------------------------------------------------------------
    // Begin EJB-required methods.  The methods below are called
    // by the Container, and never called by client code.
    //----------------------------------------------------------------
    
    /**
     * Called by Container.
     * Implementation can acquire needed resources.
     */
    public void ejbActivate() {
        System.out.println("ejbActivate() called.");
    }
    
    /**
     * EJB Container calls this method right before it
     * removes the Entity Bean from the database.
     * Corresponds to when client calls home.remove().
     */
    public void ejbRemove() {
        System.out.println("ejbRemove() called.");
    }
    
    /**
     * Called by Container.
     * Releases held resources for passivation.
     */
    public void ejbPassivate() {
        System.out.println("ejbPassivate () called.");
    }
    
    /**
     * Called from the Container.  Updates the entity bean
     * instance to reflect the current value stored in
     * the database.
     *
     * Since we're using Container-Managed Persistence, we
     * can leave this method blank.  The EJB Container will
     * automatically set our public fields to the correct values.
     */
    public void ejbLoad() {
        System.out.println("ejbLoad() called.");
    }
    
    /**
     * Called from the Container.  Updates the database to
     * reflect the current values of this in-memory Entity Bean
     * instance representation.
     *
     * Since we're using Container-Managed Persistence, we can
     * leave this method blank.  The EJB Container will
     * automatically save our public fields into the database.
     */
    public void ejbStore() {
        System.out.println("ejbStore() called.");
    }

    /**
     * Called by Container.  Associates this Bean instance with
     * a particular context.  Once done, we can query the
     * Context for environment info
     */
    public void setEntityContext(EntityContext ctx) {
        System.out.println("setEntityContext called");
        this.ctx = ctx;
    }

    /**
     * Called by Container.  Disassociates this Bean instance
     * with a particular context environment.
     */
    public void unsetEntityContext() {
        System.out.println("unsetEntityContext called");
        this.ctx = null; 
    }

    /**
     * Called after ejbCreate().  Now, the Bean can retrieve
     * its EJBObject from its context, and pass it as a 'this'
     * argument.
     */
    public void ejbPostCreate(String productID, String name, String description, double basePrice) {
        System.out.println("ejbPostCreate() called");
    }

    /**
     * This is the initialization method that corresponds to the
     * create() method in the Home Interface.
     *
     * When the client calls the Home Object's create() method,
     * the Home Object then calls this ejbCreate() method.
     *
     * NOTE: Since we're using Container-Managed persistence,
     * this method returns void.  With Bean-Managed Persistence,
     * we returned the PK.  This is because our Bean was
     * responsible for dealing with PKs and accessing
     * the database.  Now that we let the Container handle
     * persistence, the Container makes the Primary Key.
     *
     * We still need to initialize our Bean's fields with the
     * parameters passed from the client, so that the Container
     * can inspect our Bean and create the corresponding database
     * entries.
     */
    public String ejbCreate(String productID, String name, 
                            String description, double basePrice) 
        throws CreateException 
    {
        System.out.println("ejbCreate() called");
        
        setProductID(productID);
        setName(name);
        setDescription(description);
        setBasePrice(basePrice);
        
        return productID;
    }

    // No finder methods - they are implemented by Container

    //----------------------------------------------------------------
    // End EJB-required methods
    //----------------------------------------------------------------
}