jobbean.java

21天精通Java,这是一本英文书

package data;

import java.rmi.*;
import java.util.*;
import javax.ejb.*;
import javax.naming.*;

public abstract class JobBean implements EntityBean {
    private JobLocalHome jobHome; // reference to own home;
                                  // should be able to get through ctx.getEJBHome(),
                                  // but J2EE RI returns null
    private CustomerLocalHome customerHome;

    private CustomerLocal customerObj; // derived

    public abstract void setRef(String ref);
    public abstract String getRef();

    public abstract void setCustomer(String customer);
    public abstract String getCustomer();

    public CustomerLocal getCustomerObj() {
        return customerObj;
    }

    public abstract String getDescription();
    public abstract void setDescription(String description);

    public abstract LocationLocal getLocation();
    public abstract void setLocation(LocationLocal location);

    public abstract Collection getSkills();
    public abstract void setSkills(Collection skills);

    // EJB methods start here
    public JobPK ejbCreate(String ref, String customer) throws CreateException {
        // validate customer login is valid.
        try {
            customerObj = customerHome.findByPrimaryKey(customer);
        } catch (FinderException ex) {
            error("Invalid customer.", ex);
        }

        JobPK key = new JobPK(ref,customerObj.getLogin());
        // for BMP, there was a workaround here, namely to call ejbFindByPrimaryKey
        // under CMP, cannot call since doesn't exist.
        // instead, use jobHome interface ...
        try {
            jobHome.findByPrimaryKey(key);
            throw new CreateException("Duplicate job name: "+key);
        }
        catch (FinderException ex) {}

        setRef(ref);
        setCustomer(customer);
        setDescription(null);
        setLocation(null);
        return key;
    }

    public void ejbPostCreate(String ref, String customer) { }

    public void ejbHomeDeleteByCustomer(String customer) {
        // an alternative might have been to define a cascade delete relationship
        // from customer -> job; however, the customer / job relationship is
        // bean-managed rather than container-managed.
        try {
            // ctx.getEJBHome() returns null
            // Collection col = ((JobLocalHome)ctx.getEJBHome()).findByCustomer(customer);
            // work-around; access own home through JNDI
            Collection col = this.jobHome.findByCustomer(customer);
            for (Iterator iter = col.iterator(); iter.hasNext(); ) {
                JobLocal job = (JobLocal)iter.next();
                // remove job from collection
                iter.remove();
                // remove job itself
                job.remove();
            }
        }
        catch (FinderException e) {
            error("Error removing all jobs for " + customer, e);
        }
        // needed because of the explicit job.remove()
        catch (RemoveException e) {
            error("Error explicitly removing job for " + customer, e);
        }
        System.out.println("JobBean: ejbHomeDeleteByCustomer() - end");

    }

    public void ejbLoad() {
        JobPK key = (JobPK)ctx.getPrimaryKey();

        try {
            this.customerObj = customerHome.findByPrimaryKey(getCustomer()); // derived
        }
        catch (FinderException e) {
            error("Error in ejbLoad (invalid customer) for " + key, e);
        }
    }

    public void ejbStore() { }

    public void ejbPassivate() {
        setRef(null);
        setCustomer(null);
        customerObj = null;
        setDescription(null);
        setLocation(null);
    }

    public void ejbActivate() { }

    public void ejbRemove() { }

    private EntityContext ctx;

    public void setEntityContext(EntityContext ctx) {
        this.ctx = ctx;
        InitialContext ic = null;
        try {
            ic = new InitialContext();
            customerHome = (CustomerLocalHome)ic.lookup("java:comp/env/ejb/CustomerLocal");
            jobHome = (JobLocalHome)ic.lookup("java:comp/env/ejb/JobLocal");
        }
        catch (NamingException ex) {
            error("Error looking up depended EJB or resource", ex);
            return;
        }
    }

    public void unsetEntityContext() {
        this.ctx = null;
        customerHome = null;
        jobHome = null;
    }

    private void error(String msg, Exception ex) {
        String s = "JobBean: " + msg + "\n" + ex;
        System.out.println(s);
        throw new EJBException(s, ex);
    }
}