Using Java technology to implement business logic in Cocoon

source:

http://www.linuxforum.net/forum/printthread.php?cat=387301&type=post.com=java/prin

If you have a understanding of Apache Cocoon or to be involved, you may be better to use Java in CoCoon.

Realization of specific logic has doubtful. This article will show you how to use XSP (EXTENSIBLE SERVER PAGE)

And Action. There is also an example and design principles.

You may have heard some sound from Apache about Cocoon. Now, after three years of development,

Cocoon has gradually converted from a simple implementation XSL (Extensible Stylesheet Language)

Servlet grows into a full web application framework.

CoCoon is developed with Java, which is generally used as a servlet container like Tomcat as a servlet.

In this article, we will introduce two ways to use Java to implement commercial logic in Cocoon-based applications.

First, let's take a look at Cocoon.

CoCoon officially defined is an XML publishing engine, we can understand that cocoon is used to generate, convert, and process

And the framework of output data. It can also be understood that Cocoon is a different processing from a variety of data sources to apply different processing, the most

The machine after the data is output in the desired format.

We can also define Cocoon as a data stream machine. That is to say, when you use Cocoon, you define the path of the data.

Trail or flow to generate a page of web applications.

Below is some of COCOON's main basic principles:

1. Cocoon handles all the data as the SAX (Simple API for XML) event, any non-XML data must

Transfer into an XML description.

2, components that generate SAX events are responsible for processing input data

3. The serializer is responsible for processing output data to output data to the client (browser, file, etc.).

4. Developer combination generators, serializer, and other components constitute a pipe. All pipes are in a map called site map

Definition in the file.

5, match the pipe through the URI (Uniform Resource Identifier), but the URI is detached from the physical resource.

Point 5, you need to explain:

For traditional Web Server, the URI is generally mapped to physical resources.

For example, this URI

http://localhost/index.html will map to INDEX.HTML in Apache Server

HTML file.

In Cocoon, URIS and physical resources may be without any absolute relationship. You can help the URI you can

Help users browse your site better. Finally, you can organize your files to make it easy to manage and maintain.

In order to better understand the Cocoon's processing model, you can see a simple pipe.

The following example defines a page called INDEX.html. This pipe is located in the SiteMap.xmap site map:

This pipe has three steps:

The first is a generator component FileGenerator reads data from the XML file "content / mainfile.xml".

(FileGenerator actually has already defined in the map in advance, you can reference all in .cocoon through the "Type" property

Pipe components are referenced by their Type properties. )

The conversion is then performed, and the converter Traxtransformer applies the XSL StyleSheet to the introduced data.

Finally, the sequencer HTMLSerializer writes the data to the client's browser.

You may be confused, what is in connection with Java development?

We divide Cocoon's application into three parts:

1, data collection layer DATA Collection (Generation)

2, data processing and conversion layer Data Processing & Transforming

3. Output layer Data Output (Serialization)

Then, Java development is very important in Cocoon's processing conversion layer. Cocoon's conversion and processing layer are cocoon

The core of the application, through this layer of processing, logical applications, logical applications, you can get the desired output.

In Cocoon, you can have the following four ways to implement logic:

1. Use the Transformer component: They convert the incoming data according to the rules you give. Classic example

It is traxtransformer.

2. Select different components to make correct processing through different requests, session, and uri.

3, use an existing or you implement the Action.

4. Use XSP that mixed Java code and content.

This article introduces the last two methods: XSP and Action. The development of XSP and Action is in the servlet context.

Specifically, two components (actually all components) have access to Request, Response, Session, and

Context object. In some ways, a lot of logic you want to achieve will interact with these objects.

XSP

XSP is the innovation of the Cocoon project. You can compare it with JSP because they are mixed logic and content and JSP

Taglib and XSP logicsheet are also very similar.

XSP is located at the starting point of the pipe, in fact it is converted into a generator (Generator) to give the rest of the components in the pipe.

Data.

Let us look at this called Sample1.xsp simple example:

Date now = new date ();

String msg = "boo!";