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(c) Paneris 2001 Tim Joyce (timj At paneris.org)
This file describes the Melati (http://www.melati.org) shopping trolley interface developed by Paneris (http://www.paneris.org) and how to install and set it up. It assumes you have installed Melati and have created your own POEM database/melati application to which you wish to add the Shopping Trolley.
The shopping trolley system is a java package to be used with Melati. Melati is a java servlet based framework for developing HTTP applications using POEM. POEM provides an OO wrapper around an SQL database. Together Melati and POEM provide a RAD toolkit for building web sites.
The Melati Shopping Trolley Interface is designed to provide a flexible abstraction of the basic processes of allowing customers to buy goods on a website. By default, it is not integrated with POEM, and so makes no assumptions about the underlying database implementation. It does provide the following:
Because exact implementations of shopping trolleys are notoriously varied, this interface seeks to provide as much flexibility as possible. You can customise your implementation in 2 ways:
- Trolley.wm
- Details.wm
- Confirm.wm
- Order.wm
- Menu.wm
The basic process as experienced by the user is fairly typical of any online Shopping experience:
Install and test Melati from http://www.melati.org/
Download the latest Melatishopping snapshot from http://shopping.paneris.net/ and unzip or untar it. eg:
Unix users type:
cd /usr/local/ tar -xzf melatishopping_0.50.tar.gz ln -s melati_0.50 melati
Windows users should use WinZip
For Apache Jserv, this can be done either in the jserv.properties file, by adding a lines
wrapper.classpath=/usr/local/melatishopping/src wrapper.classpath=/usr/local/melatishopping/lib/melati.jar
or in your zone .properties file by adding
/usr/local/melatishopping/src,/usr/local/melatishopping/lib/melatishopping.jar
to the line beginning repositories=
These should be based on DefaultShoppingTrolley.java and DefaultShoppingTrolleyItem.java. You will (at least) have to define the following abstract methods. If you don't want to make use of a particular feature, simply "return".
ShoppingTrolley:
/**
* Set the Locale for this trolley.
*/
public Locale getLocale(){}
/**
* Load a trolley from something persistent.
*/
public void load(Integer id) {}
/**
* Save a trolley to something persistent.
*/
public void save() {}
/**
* Provide a mechanism for working out if
* this order should include a delivery charge.
*/
public boolean hasDelivery(){}
/**
* You need to provide some mechanism for calculating the delivery
* value for the order (item delivery values are calculated individually.
*/
public double getDeliveryValue() {}
/**
* Provide a mechanism for working out if
* this order should include a discount.
*/
public boolean hasDiscount() {}
/**
* If you want to apply a discount to this order, do it here.
*/
public double getDiscountRate() {}
/**
* Provide a mechanism for working out if
* this order should include VAT (default should be true).
*/
public boolean hasVAT() {}
/**
* If you want something to happen (like sending an email) when the user
* has returned from paying, do it here.
*/
public void confirmPayment(Melati melati) {}
/*
* Load in information about this product given an id.
* Perhaps this id represents a poem troid?
*/
protected void load(Integer id){};
/**
* Work out the cost of delivery for this item.
*/
public double getDeliveryValue() {}
For example, you need to specify the 2 classes you created above:
# What class implements the shopping trolley org.paneris.melati.shopping.ShoppingTrolley.trolley = <Your>ShoppingTrolley # What class implements the shopping trolley items org.paneris.melati.shopping.ShoppingTrolley.item = <Your>ShoppingTrolleyItem
The interface to the Shopping Trolley is defined in the following templates:
Trolley.wm - The initial page where you can add/remove/edit trolley items Details.wm - Collection of user details Confirm.wm - Confirmation of order Order.wm - The trolley rendered as text Menu.wm - The menu
There are many companies offering secure payment services. My current personal favorite is http://www.securetrading.com. You will need to edit Confirm.wm to supply the correct details to your chosen server.
If you need to do something (like send an email) following confirmation of payment, define the method in Your ShoppingTrolley.java:
public void confirmPayment(Melati melati) {}
This will return the template Paid.wm.
Because the callback request (typically) comes from the Payment Server, you will not have the user's shoping trolley (Session) available to them. You will therefor need to get whatever information you require from something persistent.
The alternative is to get the Payment Server to generate the emails (or whatever) for you. Most Payment Servers offer this facility.
You can add items to your shopping trolley using the following URL: http://host name /servlet zone /org.paneris.melati.shopping.Trolley/database name /Add/product id /
This will load the product with the supplied Troid, using the method:
load(Integer id){}; in org.paneris.melati.shopping.shoppingTrolleyItem
Alternatively, supply the price and description as part of the request:
?price=8.99&description=Caterpillar+May
This has obvious security considerations (users can change the price). This mechanism is best used for prototyping or for systems where orders are checked manually before payment is taken (telephone ordering etc).
Included with this distribution are 2 examples: