BeanShellServerTemplate (Brazil Project)

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sunlabs.brazil.beanshell
Class BeanShellServerTemplate

java.lang.Object
  sunlabs.brazil.template.Template
      sunlabs.brazil.beanshell.BeanShellServerTemplate (view source)

All Implemented Interfaces:: TemplateInterface

Direct Known Subclasses:: BeanShellTemplate

public class BeanShellServerTemplate
extends Template
extends Template

The BeanShellServerTemplate looks for one of the starting tags <server language="beanshell">, <beanshell>, or <bsh> in an HTML page and treats the following data up to the corresponding ending tag ( </server>, </beanshell>, or </bsh>) as a BeanShell script to evaluate. For information on BeanShell, see www.beanshell.org.

The reason that BeanShell scripts are included in an HTML page is usually to generate dynamic, server-side content. After running this template, everything between and including the starting tag and and the ending tag is replaced by all output written to the BeanShell output stream (if any).

All BeanShell fragments within a given page are evaluated in the same BeanShell interpreter. The BeanShell interpreter actually lives for the entire duration of this Template object, so the user can implement persistence across requests.

The following configuration parameters are used to initialize this template.

script: The name of the BeanShell script to evaluate when the interpreter is created. This script is only evaluated when the interpreter is created, not on every request. The variables prefix and server are set before this file is evaluated, and are references to the parameters passed to a handler init method.
root: The document root, if the script is a relative file name. If the "root" property under the template prefix is not found, the global "root" property is used. If the global "root" property is not found, the current directory is used.
debug: If this configuration parameter is present, this class replaces the starting and ending tags with comments, so the user can keep track of where the dynamically generated content is coming from by examining the comments in the resultant HTML document. By default, the starting and ending tags are completely eliminated from the HTML document rather than changed into comments.

Before evaluating each HTML document, this class sets variables in the BeanShell interpreter, which can be used to interact back with Java to do things like set the response headers:

request: Exposes the Request Java object. It is set anew at each request.
prefix: Exposes the handler prefix String.
server: Exposes the handler Server object.

If the attribute eval is present as an attribute, all constructs off the form ${...} are substituted before processing the script.

Here's a simple example of a BeanShell template:


 <html>
 <head>
 <title>BeanShell Examples</title>
 </head>
 <body>
 The global variables <code>request</code>,
 <code>prefix</code>, and <code>server</code>
 are already defined.  Here's how to add a new property:
 <bsh>
 sum = 3 + 4 + 5;
 request.props.put("sum", Integer.toString(sum));
 </bsh>
 And here's a way to list the properties contained in the request:
 <table>
 <bsh>
 e = request.props.propertyNames();
 while (e.hasMoreElements()) {
   name = e.nextElement();
   value = request.props.getProperty(name);
   print("<tr><td>" + name + "</td><td>" 
         + value + "</td></tr>");
 }
 </bsh>
 </table>
 </body>
 </html>

Field Summary

Fields inherited from class sunlabs.brazil.template.Template
`debug`

Constructor Summary
`BeanShellServerTemplate()`

Method Summary
`boolean`	`init(RewriteContext hr)` Called at the beginning of each HTML document that this `BeanShellServerTemplate` is asked to process.
`void`	`tag_beanshell(RewriteContext hr)` Processes the `<beanshell>` tag.
`void`	`tag_bsh(RewriteContext hr)` Processes the `<bsh>` tag.
`void`	`tag_server(RewriteContext hr)` Processes the `<server>` tag.

Methods inherited from class sunlabs.brazil.template.Template
`done`

Methods inherited from class java.lang.Object
`equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

BeanShellServerTemplate

public BeanShellServerTemplate()

Method Detail

init

public boolean init(RewriteContext hr)

Called at the beginning of each HTML document that this BeanShellServerTemplate is asked to process.

The first time this method is called, the initialization script is sourced into the interpreter, based on the configuration properties in the Request

Specified by:: init in interface TemplateInterface
Overrides:: init in class Template

Parameters:: hr - The request and associated HTML document that will be processed.
Returns:: true interpreter was successfully initialized false otherwise. About the only way that the initialization could fail would be due to an error sourcing the initialization script. If false is returned, an error message is logged.

tag_server

public void tag_server(RewriteContext hr)

Processes the <server> tag. Substitutes the result of evaluating the following BeanShell script into the resultant HTML document.

Parameters:: hr - The request and associated HTML document that will be processed.

tag_beanshell

public void tag_beanshell(RewriteContext hr)

Processes the <beanshell> tag. Substitutes the result of evaluating the following BeanShell script into the resultant HTML document.

Parameters:: hr - The request and associated HTML document that will be processed.

tag_bsh

public void tag_bsh(RewriteContext hr)

Processes the <bsh> tag. Substitutes the result of evaluating the following BeanShell script into the resultant HTML document.

Parameters:: hr - The request and associated HTML document that will be processed.