net.sf.basedb.clients.web.extensions
Class XJspCompiler

java.lang.Object
  org.apache.jasper.compiler.Compiler
      org.apache.jasper.compiler.JDTCompiler
          net.sf.basedb.clients.web.extensions.XJspCompiler

public class XJspCompiler
extends JDTCompiler

Class that enabled compilation of custom JSP pages that are part of an extension that uses classes from the extension JAR file (eg. a JAR file in the /WEB-INF/extensions directory).

To make this compiler work the following is required:

• The JSP file must have a '.xjsp' extension.
• This compiler class must be installed in Tomcat's /lib directory.
• The '.xjsp' extensions must be mapped to the regular JSP servlet with the 'compilerClass' parameter set to this class.

Note! This feature is still experimental. It has only been tested with some versions of Tomcat 6.0.x. This class depends on internal implementation details of Tomcat, and may or may not work with future or older versions of Tomcat.

Version:

2.7

Author:

nicklas

Last modified

$Date:2008-03-20 12:15:25 +0100 (Thu, 20 Mar 2008) $

Field Summary

static String	EXTENSIONS_URL The location where the extension system is looking for extensions.
private File	extensionsJar
private boolean	isXJsp
private long	lastModified
private static Pattern	PATH_MATCH Path to JSP must match: /extensions/[jar-file-name]/[jsp-path].xjsp group(1) = JAR name, group(2) = JSP path
static String	RESOURCES_URL The location where the extensions resources are extracted.

Fields inherited from class org.apache.jasper.compiler.Compiler

ctxt, errDispatcher, jsw, log, options, pageInfo, pageNodes, tfp

Constructor Summary

XJspCompiler()

Method Summary

protected void	generateClass(String[] smap) Called when a JSP page needs recompiling.
protected URLClassLoader	getExtensionClassLoader() Get a class loader that can load classes from the current web application as well as the extensions JAR file.
protected ClassLoader	getWebAppClassLoader() Get the class loader for the web application this JSP is located in.
void	init(JspCompilationContext ctxt, JspServletWrapper jsw) Initialises the compiler.
boolean	isOutDated(boolean checkClass) Checks if the extensions JAR file has been modified.
protected void	setContextClassLoader() Sets the context class loader if this JSP page is an extension JSP page and if the extensions JAR file has been modified since the last time the class loader was set.

Methods inherited from class org.apache.jasper.compiler.Compiler

compile, compile, compile, generateJava, getCompilationContext, getErrorDispatcher, getPageInfo, getPageNodes, isOutDated, removeGeneratedClassFiles, removeGeneratedFiles

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EXTENSIONS_URL

public static final String EXTENSIONS_URL

The location where the extension system is looking for extensions.

See Also:

Constant Field Values

RESOURCES_URL

public static final String RESOURCES_URL

The location where the extensions resources are extracted.

See Also:

Constant Field Values

PATH_MATCH

private static final Pattern PATH_MATCH

Path to JSP must match: /extensions/[jar-file-name]/[jsp-path].xjsp group(1) = JAR name, group(2) = JSP path

isXJsp

private boolean isXJsp

extensionsJar

private File extensionsJar

lastModified

private long lastModified

Constructor Detail

XJspCompiler

public XJspCompiler()

Method Detail

init

public void init(JspCompilationContext ctxt,
                 JspServletWrapper jsw)

Initialises the compiler. The JSP name is matched against the required pattern and the name of the extensions JAR file is extracted from the request path.

Overrides:

init in class Compiler

generateClass

protected void generateClass(String[] smap)
                      throws FileNotFoundException,
                             JasperException,
                             Exception

Called when a JSP page needs recompiling. We check if the extension JAR file has been modified and update the class loader if it has.

Overrides:

generateClass in class JDTCompiler

Throws:

FileNotFoundException

JasperException

Exception

isOutDated

public boolean isOutDated(boolean checkClass)

Checks if the extensions JAR file has been modified. If not, calls super.isOutDated(checkClass)

Overrides:

isOutDated in class Compiler

setContextClassLoader

protected void setContextClassLoader()
                              throws Exception

Sets the context class loader if this JSP page is an extension JSP page and if the extensions JAR file has been modified since the last time the class loader was set. This method does nothing if the JSP file is not an extensions JSP file, or if the JAR file hasn't changed since the last use.

Throws:

Exception

getExtensionClassLoader

protected URLClassLoader getExtensionClassLoader()
                                          throws Exception

Get a class loader that can load classes from the current web application as well as the extensions JAR file. The class loader for the current web application can be found in JspRuntimeContext.getParentClassLoader(). The extensions class loader is loaded from JarClassLoader in BASE.

Throws:

Exception

getWebAppClassLoader

protected ClassLoader getWebAppClassLoader()

Get the class loader for the web application this JSP is located in. Default implementation returns JspRuntimeContext.getParentClassLoader()