Introduction

OFBiz is a large complex system that is configured and programmed using file editing. There is no nifty IDE for OFBiz (Not yet anyways). To program the system you must understand fairly well how it works. As such the OFBiz system has a very steep learning curve, but once learned is a very powerfull system. With OFBiz you can develop web applications that are very robust.

Fortunately you can use OFBiz while only inderstanding some of the parts and gradualy exapnd your knowledge.

This guide is organized (I use that term loosely) in chronological order as to how I discovered and learned about OFBiz.

I used OFBiz about 6 months ago and now have reasons to use it again. It is such a pain to learn OFBiz (thought well worth it) that I figure I can save you the same pain with this nifty guide.

DAY 1

Next I had to get the environment set up. This consists of setting the CLASSPATH and the PAT variables. I took the approach of batch scripts for setup because I frequently switch between environments and projects. My project is/was to be called MailRoute so I made a directory called C:\MailRoute. In that directory I put a script called s.bat for setup. s.bat looks like this...

-------------------------------------------------------
set PATH=C:\jdk13\bin;C:\cygwin\bin;%PATH%

set CLASSPATH=C:\jaf-1.0.2\activation.jar;%CLASSPATH%
set CLASSPATH=C:\javamail-1.3\mail.jar;%CLASSPATH%
set CLASSPATH=C:\jdk13\lib\tools.jar;%CLASSPATH%
set CLASSPATH=C:\javamail-1.3\lib\smtp.jar;%CLASSPATH%
set CLASSPATH=C:\javamail-1.3\lib\pop3.jar;%CLASSPATH%
-------------------------------------------------------

Ant:

Next I needed an editor. I did a first helloworld.java with the DOS' EDIT command which is readly bad for java code, but it proved the compiler is working.

Then I got Forte for Java from java.sun.com and tried it. One of my co-workers said that NetBeans is the open source project for Forte so I went to http://www.netbeans.org and got that.

The lack of a mouse wheel in NetBeans was realy annoying so I got the module from http://nbmousewheel.sourceforge.net/ and it worked right away. (Yay Radim Kubacki!)

NetBeans tip: Type ctrl-shift-f to auto format the whole edit buffer.

I also got JEdit for when I want a quick edit of a file and don't want to wait for NetBeans to come up. (NetBeans is very slow at startup.)

Now I have a good editor. Check out the other modules from the Tools->Update Center menu.

I then spent a few hours developing a core java class called MailRoute that reads form a mailbox and writes to several addresses after parsing some contents out for database lookup. No database yet, just hard-coded values.

DAY 2

OFBiz Install:

Next I needed to get OFBiz to work.

I got the latest release and put it in a directory called C:\OFBiz

Then I had to get a database and server.

Resin:

MySQL:

OFBiz intial Config:

Goto the OFBiz directory and look around a bit. The file system is overwhelming and it is very hard to find where all the pieces are.

We first have to get some configuration setup according to where you installed OFBiz.

We need to get the entity engine (The database engine) pointed at the database you installed. In C:\OFBiz\commonapp\etc\entityengine.xml is where this is defined. There are many entries in the file for all the different databases supported. You need to find the line like...

<delegator name="default" entity-model-reader="main" entity-group-reader="main">
  <group-map group-name="org.ofbiz.commonapp" datasource-name="localmysql" /> 
</delegator>

Your now ready to go. I put a reference to the ofbiz.bat file (from the setup/resin/ofbiz.bat) on my desktop and on the task bar since you will be starting this up rather frequently. Run the batch file. You should see a COMMAND window come up and a little GUI in the upper left corner of the screen for Resin. LOTS of stuff will scroll by. Wait for it to calm down for a bit.

(To kill OFBiz just click on the Quit button in the GUI.)

Now that OFBiz is running you need to check it and populate the database.

Open a browser and goto http://localhost:8080
You should see the Resin default home page.
Now goto http://localhost:8080/webtools
This is the party manager, but you have to log in.
The defualt is login admin, password ofbiz (but its a secret so don't tell anyone)

Don't do anything until you click near the bottom of the screen where it says...
NOTE: If you have not already run the installation data loading script, click here to run it.

You'll get a screen that lets you define which script to run. The default is the correct one so click on the button labeled Load Data.

This will run the installation script and put about 460 tables into the ofbiz database.

It takes a while...
And a while longer...
and longer...
but only has to be done once...
unless you change the schema...
which is unlikely...

OK, now OFBiz is running.

Lets do some fun stuff:

http://localhost:8080/ecommerce

Wow, a whole shopping cart.

How is the catalog created?

http://localhost:8080/catalog This is the catalog maintanence screens. Poke around some. There are a lot of screens here.

Also try:

About Party:

How Do I Deal With All These Entities!

Schema

For example,
A Product has fields for lots of auxiliary data, most of which can be blank. Any code you write should be prepared for blanks in the data. If the Product.detailImageURL is blank then the catalog will show a little "no picture available" image instead. Thus you do not need to understand much of the schema to get along in OFBiz.

Instances

ALWAYS look at the instances and schema before dashing off and creating new types of entities or instances of entities. For example, I was about to create a new ProductType of VOICE_SUBSCRIPTION, but when I looked at the ProdcutType instances, there was SERVICE, GOOD, and a few others. I realized that what I was doing was a SERVICE and the other partos of OFBiz know that you don't ship a SERVICE in a box! I then looked at ProductCategory and this is where you define VOICE_SUBSCRIPTION.

The moral of the story is - Study alot, code a little.

Why is the entity schema so good? Because the OFBiz founders copied it all from a standard book of schemas for eCommerce! This schema has probably 100 man years of thought and experience in it.

DAY 3

Here you have to start thinking a bit. Is what you want to do almost exactly like what is there? For example are you simply doing an online catelog and shopping cart? In that case you simply customize a little of what is there.

Is what your doing something not yet done? (In my case I'm writing a subscription manager for subscribing to voice messages.) Then you need to create a new project.

First copy the nearest thing to what you are doing to a new directory. I copied C:\OFBiz\partymgr to
c:\OFBiz\subscriptionmgr.

Next you need to tell Resin (the web server) about the new project. The file C:\resin-2.1.4\conf\resin.config needs a new line near the bottom like <web-app id="/subscriptionmgr" app-dir="C:/ofbiz/subscriptionmgr/webapp"/> where you see the other OFBiz lines.

Now If you go in the browser and goto http://localhost:8080/subscriptionmgr you should get a screen exactly like the partymgr screen. (In fact a bit too exactly.)

To compile the new stuff you use ant. Simply get into a COMMAND window, run your s.bat to get the CLASSPATH and PATH correct. Next goto the OFBiz top level directory and type ant.

Everything will build. If you want to just build your project directory then first goto the core directory and run ant. Now you can goto your project directory (subscriptionmgr) and type ant to do a quick build.

The bit with core is needed because the webapp-core.jar file is removed from the core area at the end of a top level build so it won't be found before the same file in your webapps directory when the CLASSPATH is scanned, yet it is needed in the core area for project level builds. This only realy matters if one of your projects needs a special webapps-core.jar file. If you don't do the build in the core directory then the project build will complain that some core classes can't be found. Now lets change the basic verbage on the screens.

First lets look at how screens get made. When you ask for http://localhost:8080/subscriptionmgr the first thing that resin does is resolve it to C:/ofbiz/subscriptionmgr/webapp and then to index.jsp What index.jsp does is redirect to control/main Control is mapped to a servlet in OFBiz that is the gate keeper for all requests. Control is what is called a controller servlet architecture. The controller takes actions (in this case "main") and mapps them to actual pages. But it does much more... In the file C:\OFBiz\subscriptionmgr\webapp\WEB-INF\controller.xml is where the mapping is defined. The lines...

    <request-map uri="main">
        <security https="true" auth="true"/>
    	<response name="success" type="view" value="main"/>
    </request-map>

    <view-map name="main" page="findparty" type="region"/>

    <define id='findparty' region='MAIN_REGION'>
        <put section='title'>Find Party</put>
        <put section='content' content='/party/findparty.jsp'/>
    </define>

    <define id='MAIN_REGION' template='/templates/main_template.jsp'>
        <put section='title'>Application Page</put> <!-- this is a default and is meant to overridden -->
        <put section='header' content='/includes/header.jsp'/>
        <put section='appbar' content='/includes/appbar.jsp'/>
        <put section='error' content='/includes/errormsg.jsp'/>
        <put section='content' content='/main.jsp'/> <!-- this is a default and is meant to overridden -->
        <put section='footer' content='/includes/footer.jsp'/>
    </define>

Given this intro, lets customize or little app. First goto the file C:\OFBiz\subscriptionmgr\webapp\WEB-INF\web.xml and look for everywhere it says Party as in Party Manager, and change it to Subscription Manager. Now if you look at http://localhost:8080/subscriptionmgr the titles have changed. It would be nice to change the menus to what we need so edit the file C:\OFBiz\subscriptionmgr\webapp\includes\header.jsp (You better understand HTML and JSP's at this point. If not your in the wrong tutorial and way over your head!) Notice these points of interest...

The ofbiz imports at the top.

<%@ taglib uri="ofbizTags" prefix="ofbiz" %>

<jsp:useBean id="security" type="org.ofbiz.core.security.Security" scope="request" />

EntityField.run("partyGroup", "groupName", "", "", pageContext);

I took this file and took out most of the menu items leaving just Main (Signup) and Edit Subscription.

Now we need a page that does something, which in my case is to hook the MailRoute code I wrote to OFBiz. I put the MailRoute class in the directory called C:\OFBiz\subscriptionmgr\src\com\asg and made a new class called MailRouteWorker that will have methods for generating HTML about subscriptions. The MailRoute class needs to know things like email account name, password, server, and email type (pop3 or smtp).

This is done via. a properties file I put in C:\OFBiz\subscriptionmgr\webapp\WEB-INF\subscriptionmgr.properties I used the NetBeans properties editor so it was easy to create. Then in the MailRoute I put some code...

import org.ofbiz.core.entity.*;
import org.ofbiz.core.service.*;
import org.ofbiz.core.util.*;
...
    public String sourceServer;
    public String sourceLogin;
    public String sourcePassword;
    public String sourceProtocol = "pop3";
    
    public String destinationServer;
    public String destinationLogin;
    public String destinationPassword;
    public String destinationProtocol = "smtp";
    
    public String companyTitle = " ";
    public int verbose = 0; // 0 none, 1 some, 2 lots.
    java.net.URL subscriptionmgrPropertiesUrl = null;
    int sourcePollingIntervalMs = 60000;
...
    private void setupEnv(ServletContext ctx) {
        try {
            subscriptionmgrPropertiesUrl = ctx.getResource("/WEB-INF/subscriptionmgr.properties");
        }
        catch ( java.net.MalformedURLException e ) {
            Debug.logWarning(e);
        }
        
        System.out.println("MailRoute Creation.");
        try {
            Integer.parseInt(UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "verbose", "0"));
        }
        catch (Exception ex) {
        }
        companyTitle = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "colmpanytitle", "Subscription Router");
        // TBD The real account and password.
        sourceServer = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "sourceMailHost", "notset");
        sourceLogin = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "sourceMailLogin", "notset");
        sourcePassword = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "sourceMailPassword", "notset");
        sourceProtocol = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "sourceMailProtocol", "pop3");
        destinationServer = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "destinationMailHost", "notset");
        destinationLogin = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "destinationMailLogin", "notset");
        destinationPassword = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "destinationMailPassword", "notset");
        destinationProtocol = UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "destinationMailProtocol", "smtp");
        try {
            sourcePollingIntervalMs = Integer.parseInt(UtilProperties.getPropertyValue(subscriptionmgrPropertiesUrl, "sourceMailPollingInterval", "60000"));
        } catch (Exception ex2) {
        }
    }

The loggin could be done better but I haven't figured out that part yet.

Now the MailRoute code needs to be called once a minute.  Timers are done with the scheduler in the Service 
Engine that is used by the Workflow Engine.
I haven't done that part yet so stay tuned for more on this in the future.


 
 
 

DAY 4
[ you may notice the DAY # notes here.  That is how long it has taken to figure out what fits in
  a few brief pages.  This knowledge was gained by either browsing code, asking David Jones (Mr. OFBiz)
  or by asking another employee (Dustin Caldwell) that works with me lots of little questions, but mostly
  by code browsing.]

Getting the editSubscription page up:

I took the main.jsp page and copied it to a page called editSubscription.jsp.
Then I modified the webapp/WEB-INF/controller.xml by copying the entry for main
and renaming main to editsubscription (in 2 places).  Then changed the regions.xml file too.
I made the link in header.jsp (over in the includes directory) where the Edit Subscription button
is defined in HTML to link to /editsubscription

This may seem strange, but what happens is that the controller gets the command editsubscription.
Since the controller.xml entry calls for auth if the user is not logged in they are kicked to the login
screen and once they login the jump back to the editSubscription screen.

Now I need to put some code in the MailRouteWorker.java file to get subscription state from the entity engine
and into HTML and to the JSP.  Here is the MailRouteWorker.java in it's partialy programed state which is
where I am now.

I have put in comments about interesting features.

Some notes are in order here about entity management.
First you have to have a delegator to do anything with an entity.
Second, you can get an object from the entity engine, called a GenericValue
from the delegator.
The delegator is gotten in the JSP with...
<jsp:useBean id="delegator" type="org.ofbiz.core.entity.GenericDelegator" scope="request" />

With this bean included then the variable delegator is defined.
The line in the JSP that calls this getHTMLSubscriptionList method is...
<DIV class='tabletext'><%=MailRouteWorker.getHTMLSubscriptionList(delegator, request)%></DIV>


delegator.findByAnd is very uesfull and lets you find objects in a table by several criteria
in an AND fashion.
Though this code does not do it (yet) if you change a field of a GenericValue
such as person.set("lastName", newLastName)
You then call person.store() to flush the change(s) to the database.


package com.asg;

// Dustin, search for the lines with TBD on them.
// R. Keene

import java.util.*;

import javax.mail.*;
import javax.mail.internet.*;
import javax.servlet.*;
import javax.servlet.jsp.*;
import javax.servlet.http.*;

import com.sun.mail.pop3.*;
import com.sun.mail.smtp.*;

import org.ofbiz.core.entity.*;
import org.ofbiz.core.service.*;
import org.ofbiz.core.util.*;
import org.ofbiz.core.security.*;

public class MailRouteWorker {
    public final static String checkBoxPrefix = "mailrouteProdCB";
    
    public static String getHTMLSubscriptionList(GenericDelegator delegator, HttpServletRequest request) {
        try {
            boolean hit = false;
	    // Use StringBuffer for fast building of HTML constructs.
            StringBuffer sb = new StringBuffer();
            
	    // SiteDefs is a class that defines the strings used in the session for common parts.
	    // In this case PERSON is the Person entity that the security system validated at login.
            GenericValue person = (GenericValue) request.getSession().getAttribute(SiteDefs.PERSON);
            if(person == null) {
                return "Can't identify you.";
            }
            
	    // Now get the products of type SERVICE and category VOICE_SUBSCRIPTION
            // This is a collection.  We show them in the form as a list with checkboxes next to them.
 	    // The delegator is the top level handle to the entity engine.  You have to have one of these to
	    // do anything with the database.
	    // UtilMisc.toMap is a nifty method that takes key:value pairs and makes a Map out of them.
            Collection availableSubscriptions =
            delegator.findByAnd("Product", UtilMisc.toMap("productTypeId", "SERVICE", "primaryProductCategoryId", "VOICE_SUBSCRIPTION"));
            if(availableSubscriptions == null) {
                return "Product search returned null.";
            }
            
            sb.append("<B>Subscription List for ");
     	    // Here we get the firstName field of the person object.
            sb.append((String)person.get("firstName"));
            sb.append(" ");
            sb.append((String)person.get("lastName"));
            sb.append("</B><BR>");
            
            Iterator i = availableSubscriptions.iterator();
            while(i.hasNext()) {
                GenericValue e = (GenericValue)i.next();
                sb.append("<INPUT type='checkbox' name='");
                sb.append(checkBoxPrefix);
                sb.append((String)e.get("productId") + "' ");
                sb.append((isSubscribed(delegator, person, e) ? "checked" : "") + ">");
                sb.append((String)e.get("productName") + " - " + (String)e.get("description"));
                sb.append("<BR>\n");
            }
            
            return sb.toString();
        } catch(Exception ex) {
            return "Exception getting subscriptions list: " + ex.getMessage();
        }
    }
    
    public static boolean isSubscribed(GenericDelegator delegator, GenericValue person, GenericValue product) {
        try {
            Collection subscriptions = delegator.findByAnd("Subscription",
            UtilMisc.toMap("partyId", person.get("partyId"), "productId", product.get("productId")));
            if(subscriptions != null && subscriptions.size() > 0) {
                return true;
            }
        } catch (Exception ex) {
        }
        
        return false;
    }
    
}




Entity creation and destruction.
Ok, next we want ot save the subscriptions that are checked in the GUI on the browser.
I added lines to the editSubscription.jsp like this...
<%
    if(request.getParameter("saveSubscription") != null) {
        MailRouteWorker.updateSubscriptions(delegator, request);
    }
 %>

And FORM tags to put the checkboxes I generate in a FORM.  The FORM line is like this...
<form method="post" action='<ofbiz:url>/editSubscription?saveSubscription=1</ofbiz:url>' name="editeftaccountform" style='margin: 0;'>

Now when the jsp post back to it's self the getPArameter("saveSubscription") will call my code in the worker.

In the worker the updateSubscriptions method scans the available subscriptions and either creates or deletes the
Subscription entities according to how the checkboxes are set.

To create a new instance of an entity you call 
delegator.makeValue
The problem is you need a unique ID for the new item (usualy) so there is a function in OFBiz
called delegator.getNextSeqId that will do this.  ALWAYS pass the name of the entity type to
getNextSeqId.  NEVER pass some other name.  The getNextSeqId keeps all the variou sequences in a DB table
and updates it as needed.  For speed ID's are gotten in blocks of 10. (OK, you realy didn't need to know that
but it's cool.)
Once the entity is created you need to create it in the actual DB table.  That is what delegator.create(...)
does.

Note: Why isn't all this more automatic? Because you might want to create entities in memory, with no intent of ever saving
them and then destroy them.
Note: Products have a productId that is not usualy numeric.  Instead it is the companies product id 
which could be anything.

To destroy en entity it's easy. Simply call the remove method on the entity.

Here is the code for updateSubscription and setSubscribed...


    public static boolean setSubscribed(GenericDelegator delegator, GenericValue person, GenericValue product, boolean subscribed) {
        try {
            System.out.println("In setSubscribed: " + subscribed);
            Collection subscriptions = delegator.findByAnd("Subscription",
            UtilMisc.toMap("partyId", person.get("partyId"), "productId", product.get("productId")));
            System.out.println("setSubscribed: There are " + subscriptions.size() + " subscriptions for " + person.get("partyId") + " and product " + product.get("productId"));
            if(subscribed) {
                if(subscriptions == null || subscriptions.size() == 0) {
                    // Not subscribed, so add it.
                    System.out.println("In setSubscribed: Create subscription entry.");
                    GenericValue sub  = delegator.makeValue("Subscription",
                        UtilMisc.toMap(
                            "subscriptionId", delegator.getNextSeqId("Subscription").toString(),
                            "partyId", person.get("partyId"),
                            "productId", product.get("productId")));
                    System.out.println("In setSubscribed: Create subscription entry. Saved. new id is " + sub.get("subscriptionId"));
                    delegator.create(sub);
                    System.out.println("In setSubscribed: stored");
                }
            } else {
                if(subscriptions != null && subscriptions.size() > 0) {
                    // Subscribed, so remove it.
                    Iterator i = subscriptions.iterator();
                    while(i.hasNext()) {
                        GenericValue sub = (GenericValue)i.next();
                        System.out.println("In setSubscribed: Removing subscription entry.");
                        sub.remove();
                        System.out.println("In setSubscribed: Removing subscription entry.");
                    }
                }
            }
        } catch (Exception ex) {
        }
        return true;
    }
    
    /** Returns true if it succeeds.
     **/
    public static boolean updateSubscriptions(GenericDelegator delegator, HttpServletRequest request)
    throws GenericEntityException {
        System.out.println("Saving subscription.");
        GenericValue person = (GenericValue) request.getSession().getAttribute(SiteDefs.PERSON);
        
        Collection availableSubscriptions =
        delegator.findByAnd("Product", UtilMisc.toMap("productTypeId", "SERVICE", "primaryProductCategoryId", "VOICE_SUBSCRIPTION"));
        if(availableSubscriptions == null) {
            System.out.println("No Product selected?");
            return false;
        }
        
        Iterator i = availableSubscriptions.iterator();
        while(i.hasNext()) {
            GenericValue e = (GenericValue)i.next();
            
	    // In our case checkBoxPrefix is "mailrouteProdCB" so the cbName might 
	    // be like "mailrouteProdCBMESSAGE_OF_THE_DAY"
            String cbName = checkBoxPrefix + (String)e.get("productId");
            System.out.println("Looking for checkbox " + cbName);
            if(request.getParameter(cbName) == null) { // Checkbox Off
                setSubscribed(delegator, person, e, false);
            } else { // Checkbox On
                setSubscribed(delegator, person, e, true);
            }
        }
        System.out.println("Done updateSubscriptions.");
        return true;
    }


Day 5 
Todays task is to get the MailRouter to be called once a minute.  
This is done via the workflow engine.

The services engine allows you to have a chunk of Java code, SOAP, or bsh
get called and return a response.  We need to create a service, that when called,
checks all the mail boxes for mail and then forwards the mail with some changes, to
all the subscribed people.

First I wrote the class called MailRoute.java and tested it independent of the OFBiz
environment.  Next it needs to be put in the environment so I put it in
C:\OFBiz\subscriptionmgr\src\com\asg\MailRoute.java

Properties in Services
Next the service needs to get at some properties such as the mail server name, login,
password and such.  I created a properties file with all of this and put it in
the webapps directory.

There is a problem here.  Services do not run as servlets or in a servlet 
context, so
the propertiy file will not be findable in the webapps directory. Instead I need to
use the standard Java call 

ResourceBundle bund = ResourceBundle.getBundle("subscriptionmgr");

to get to it.  This will look for subscriptionmgr.resource in the CLASSPATH.
I modified the build.xml script for subscriptionmgr to include a copy of the
resource file to the lib directory so it will get bundled into the .jar file
along with the MailRoute.class and MailRouteWorker.class.

    <target name="jar" depends="classes">
    	<copy file="${webapp.dir}/WEB-INF/subscriptionmgr.properties" tofile="${build.dir}/jar/subscriptionmgr.properties" />
        <jar jarfile="${lib.dir}/${name}.jar" basedir="${build.dir}/jar" />
    </target>


Note: This means that if you change the properties file you need to rebuild
or re-put it in the jat file.  This is not as nifty as a properties file in the
webapps directory, but then services aren't running in a Servlet Context.

Note: If you put it directly in the lib directory it will get deleted when the
build process cleans up before building the code!

Now the properties can be loaded.


        ResourceBundle bund = ResourceBundle.getBundle("subscriptionmgr");
        if(bund == null) {
            throw new Exception("MailRoute.setupEnv could not find the resource file subscriptionmgr.properties. (Not in the classpath)");
        }
        
        System.out.println("MailRoute Creation.");
        try {
            String v = bund.getString("verbose");
            if(v == null)
                v = "0";
            Integer.parseInt(v);
        }
        catch (Exception ex) {
        }
        companyTitle = bund.getString("subjectPrepend");
        if(companyTitle == null)
            companyTitle = "Subscription Router";
        // TBD The real account and password.
        sourceServer = bund.getString("mailroute.source.host");
        if(sourceServer == null)
            sourceServer = "notset";
	... etc ...


The Service Function
You now need to define the actual method that is called and tell the service engine
how to find it.

In webapp/WEB-INF/web.xml there is an entry to start services.
It looks like this.

  <context-param>
    <param-name>serviceReaderUrls</param-name>
    <param-value>/WEB-INF/services.xml</param-value>
    <description>Configuration File(s) For The Service Dispatcher</description>
  </context-param>>



I copied the services.xml file from another directory (use find to find one), removed
most of the entries and edited it so it looks like this.

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE services 
  PUBLIC "-//OFBiz//DTD Services Config//EN" 
  "http://www.ofbiz.org/dtds/services.dtd">

<services>
  <description>Subscription Manager Services</description>
  <vendor>ASG</vendor>
  <version>1.0</version>
	
  <!-- Subscription Manager services -->
  <service name="checkEmailService" engine="java" 
    location="com.asg.MailRoute" invoke="checkEmailService">
  </service>  
</services>



Then in MailRoute.java I have a function that looks like this.

    /** Check for mail to route, and route it. */
    public static Map checkEmailService(DispatchContext ctx, Map context) {
        Map result = new HashMap();
        System.out.println("Checking server in checkEmailServer service.");
        try {
            (new MailRoute()).checkServer(ctx);
        } catch (Exception ex) {
            System.out.println("Exception in MaiRoute service: " + ex.getMessage());
        }
        System.out.println("Done checking in checkEmailServer service.");
        return result;
    }



The checkEmailService method is important.  It takes a Map which is key/value pairs
for the parameters being passed in.  And returns a Map that is the return values, if any.
In the services.xml file you can specify parameters. 

The DispatchContext lets you get at the EntityEngine and such.

Remember, the service may not be called from within a Servlet or JSP so there is
no ServletContext, HttpServletRequest or anything like that.  The service 
is pure business logic.



Searching for Entities by Primary Key

Next I need to fill in a method that I has stubbed-out to get a list of email
address of the people subscribed to a given distribution list.  I have
the From: email address of the message, and two variable called M and U that are
parsed out of the contents of the incomming email.

I realize that I need to add a field to Product to contain the key in the email
parsed parameters (M, U or the emai address). But, in OFBiz you don't need to
add to the schema.  Instead there is a entitiy called ProductAttribute.
How did I find that? I went into the schema viewer and found Product, then
looked at the Relation section of Product and saw the ProductAttribute reference.
ProductAttribute has a productId, productAttrName, value and type.
These can be used pretty much hoever you want.
I need to create a ProductAttribute with attrName of "VOICE_SUBSCR_SOURCE"
(which I just made up) and set the value to the From: email of the incomming email
parsed data.

In fact the realy fast way to do this is get all the ProductAttributes where
attrName is VOICE_SUBSCR_SOURCE and the attrValue is whatever From: is.
Hey, that sounds almost like an SQL statement.  Fortunately I don't have to
deal with SQL.

 OK, If you must know, the incomming email has a URL in it that has parameters
U and M in it.  I parse the embedded URL and then foward the exact URL in 
a new email with a different Subject, From, and body, to all the subscribers.
This way the boss can send a email with a reference to a voice server to all the
employees, etc.


Here is the code to get the source email From converted to a Product.

    public static GenericValue convertEmailSourceAddressToProduct(String m, DispatchContext ctx) {
        try {
        GenericDelegator delegator = ctx.getDelegator();
        Collection theProductAttrs = delegator.findByAnd("ProductAttribute", 
            UtilMisc.toMap("attrName", "VOICE_SUBSCR_SOURCE", "attrValue", m));
        if(theProductAttrs.size() == 0) {
            return null;
        }
        // We expect just one entry. Any more are ignored.
        Iterator i = theProductAttrs.iterator();
        GenericValue theFirstProductAttr = (GenericValue)i.next();
        GenericValue theProduct = delegator.findByPrimaryKey("Product", 
            UtilMisc.toMap("productId", theFirstProductAttr.get("productId")));
        return theProduct;
        } catch (Exception ex) {
            System.out.println("convertEmailSourceAddressToProduct: Exception: " + ex.getMessage());
            return null;
        }
    }



 
 
 

Primary Keys and Entities
Entities have a Primary Key or PK that is usualy a single index column.  For example
the Product table PK is the productId.  The delegator has a call findByPrimaryKey
that can find a single Entity (GenericValue) very quickly.

You can also find records by several columns in a AND or OR fashion with
delegator.findByAnd and such.  These methods take a Map of key/value pairs
that define what to search for.

Next I need to go into the entity data editor and manualy add the
ProductAttributes.  Later I may make a nifty GUI to make this easy.

Another Search - By AND
The people that have subscribed have a partiId and a entity called Person.
There are ContactMech (contact mechanismattachements that can be related to
a Party so what I'll do is get all Subscription entities for a given Product.
The Product is the subscription list, and the Subscription is a person's subscription to
that list.

Once I have the list of Subscriptions, I can get the ContactMeth of 
ContactMechType EMAIL_ADDRESS for the party that owns the Subscription.
If they don't have an email address then they get skipped.

This sounds complicated but actualy the code is fairly simple and nicely illustrates the use
of the entity engine.

            Collection c = new ArrayList();
            GenericValue prod = convertEmailSourceAddressToProduct(theFromAddress, ctx);
            if(prod != null) {
                GenericDelegator delegator = ctx.getDelegator();
                // Find all the subscribers to this Product.
                Collection subscriptions = delegator.findByAnd("Subscriber",
                	UtilMisc.toMap("productId", prod.get("productId")));
                Iterator i = subscriptions.iterator();
                while(i.hasNext()) {
                    GenericValue sub = (GenericValue)i.next();
                    // Find the email address of the party
                    GenericValue emailEntity = delegator.findByPrimaryKey("ContactMech",
                    	UtilMisc.toMap("contactMechTypeId", "EMAIL_ADDRESS",
                    		       "partyId", sub.get("partyId")));
                    if(emailEntity != null) {
                        String em = (String)emailEntity.get("infoString");
                        if(em != null && em.length() > 0) {
                            c.add(em);
                        }
                    }
                }
            }



Why The Entity Engine
This is a good time to stop and think about why the entity engine is a Good Idea.

The normal way to access databases in Java is via JDBC.  There are several problems
with the direct approach.  The biggest problem is maintaining 460 different SELECT, INSERT,
UPDATE,DELETE statements.  Every time a table changes you have to fix your code.

Another approach (One that I have implemented and used) is the auto-code writer
approach.  The one I did was called CodeCrank and took an XML table definition file,
much like the entity definition file, and a code template file(s) and generated 
java code to make class definitions that knew how to do all the database stuff.
This approach is also how the earliest OFBiz entity engine worked!
It turns out to be a bad approach (though very high performance) because whenever the
schema changes the class definitions change.  Thus a field e.g. DateOfBirth, could
suddenely vanish, and now your code won't compile and run.

The entity engine instead treats database columns as key/value pairs of an object.
Since all fields are refered to by strings, if a column vanishes the worst you will get
is null, which you need to be prepared to handle anyways.
 
The .Net framework works almost exactly like the entity engine. (Was that blashpemy there?)

The entity engine is not good at loading zillions of objects quickly.  For example
if you want to load a 5 million phone number to address mappings into a database so
your web site can do reverse lookups, don't use the entity engine.

The correct approach would be to create a class called PhoneAddr and an inner class
called PhoneAddrRec and write custom code to load it realy quickly from the database
and put the 'Recs in two Hashtables, one by phone, and the other by address.
Then have a function you can call to do searches.
You also might want a custom JDBC-style method to store changes quickly.

The second great reason for using the entity engine is that the huge intimidating schema
actual is usefull.  Issues that you may have never anticipated are already
in the schema and resolved.  For the entire programming of the subscriptionmgr project
I have not needed to change a single thing in the schema!

In a realy large project the single place where programmers collide the most is
in the schema.  One programmer's change can break everyone else's code.
Also you might end up with several tables that do the same thing but by different names!


Stuff at the End of this File
If you see any typos, errors, or just plain stupid ideas, feel free to email
me with your corrections, fixes, or own stupid ideas.

Also if you liked this doccument or found it usefull, let me know too.  
It encourages me to keep improving the doccument.

Richard Keene, [email protected]