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

java.lang.Object
  net.sf.basedb.clients.web.extensions.ServletLoader

public class ServletLoader
extends Object

Loads servlet definitions from an XML file. The file format is a simplified version of the format allowed for web.xml files in Tomcat. We have kept only the <servlet> tag and it's subtags.

Version:

2.7

Author:

nicklas

Last modified

$Date: 2008-09-11 22:05:50 +0200 (Thu, 11 Sep 2008) $

Field Summary

private static String	namespace The name of the servlets namespace.
private static String	schemaFileURL The URL pointing to the servlets.xsd schema.
private List<ServletWrapper>	servlets
private Document	validatedDom

Constructor Summary

ServletLoader()
Create a new XML loader instance.

Method Summary

List<ServletWrapper>	getServlets() Get a list with all loaded servlet definitions.
boolean	hasValidFile() Checks if an XML file has passed validation in the validateXmlFile(InputStream, String) method.
protected Document	loadDocument(InputStream xmlFile, String filename) Load and validate the XML file.
void	loadLastValidatedFile(ClassLoader classLoader, boolean clear) Continue loading servlet definitions from the last validated XML file.
protected Class<? extends Servlet>	loadServletClass(String className, ClassLoader classLoader) Load the servlet class.
protected int	loadServlets(Document dom, ClassLoader classLoader) Load the servlet definitions from an XML document.
void	loadXmlFile(InputStream xmlFile, String filename, ClassLoader classLoader, boolean clear) Load a servlet definition XML file.
void	validateXmlFile(InputStream xmlFile, String filename) Validate an XML file against the servlet definition schema.

Methods inherited from class java.lang.Object

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

Field Detail

schemaFileURL

private static final String schemaFileURL

The URL pointing to the servlets.xsd schema.

namespace

private static final String namespace

The name of the servlets namespace.

See Also:

Constant Field Values

validatedDom

private Document validatedDom

servlets

private List<ServletWrapper> servlets

Constructor Detail

ServletLoader

public ServletLoader()

Create a new XML loader instance.

Method Detail

loadXmlFile

public void loadXmlFile(InputStream xmlFile,
                        String filename,
                        ClassLoader classLoader,
                        boolean clear)
                 throws JDOMException,
                        IOException,
                        ClassNotFoundException,
                        NoSuchMethodException,
                        IllegalAccessException

Load a servlet definition XML file. This method may be called multiple times with different XML files. The loading may also be done by a two-step process where the first step validates the file and the second step loads the extensions. See validateXmlFile(InputStream, String) and loadLastValidatedFile(ClassLoader, boolean).

Parameters:

xmlFile - An input stream to read the XML data from

filename - The original filename the stream is coming from, or null if not known. This value is only used when generating error messages

classLoader - The classloader to use when loading classes that are named in the XML file, or null to use the default classloader (=the same class loader that loaded the BASE core classes)

clear - TRUE to clear all already loaded servlets before loading the servlets in this file

Throws:

JDOMException - If validation of the XML file fails

IOException - If there is an error reading the XML file

ClassNotFoundException - If a servlet class named in the XML file can't be found

NoSuchMethodException - If a servlet class doesn't implement a public, no-argument constructor

IllegalAccessException - If a servlet class constructor isn't public

See Also:

validateXmlFile(InputStream, String), loadLastValidatedFile(ClassLoader, boolean)

validateXmlFile

public void validateXmlFile(InputStream xmlFile,
                            String filename)
                     throws IOException,
                            JDOMException

Validate an XML file against the servlet definition schema. If the file is valid you may continue to load the servlet definitions. See loadLastValidatedFile(ClassLoader, boolean).

Parameters:

xmlFile - An input stream to read the XML data from

filename - The original filename the stream is coming from, or null if not known. This value is only used when generating error messages

Throws:

JDOMException - If validation of the XML file fails

IOException - If there is an error reading the XML file

loadLastValidatedFile

public void loadLastValidatedFile(ClassLoader classLoader,
                                  boolean clear)
                           throws ClassNotFoundException,
                                  IllegalAccessException,
                                  NoSuchMethodException

Continue loading servlet definitions from the last validated XML file. This is the second step in a two-step process and requires that validateXmlFile(InputStream, String) has been successfully called first.

Parameters:

classLoader - The classloader to use when loading classes that are named in the XML file, or null to use the default classloader (=the same class loader that loaded the BASE core classes)

clear - TRUE to clear all already loaded servlets before loading the servlets in this file

Throws:

ClassNotFoundException - If a servlet class named in the XML file can't be found

NoSuchMethodException - If a servlet class doesn't implement a public, no-argument constructor

IllegalAccessException - If a servlet class constructor isn't public

hasValidFile

public boolean hasValidFile()

Checks if an XML file has passed validation in the validateXmlFile(InputStream, String) method. If so, the loadLastValidatedFile(ClassLoader, boolean) can be called to continue loading the servlet definitions.

Note that once the file has been loaded this flag is reset to FALSE.

Returns:

TRUE if a file has been validated, FALSE otherwise

getServlets

public List<ServletWrapper> getServlets()

Get a list with all loaded servlet definitions.

loadDocument

protected Document loadDocument(InputStream xmlFile,
                                String filename)
                         throws IOException,
                                JDOMException

Load and validate the XML file.

Returns:

A JDOM document object

Throws:

IOException

JDOMException

loadServlets

protected int loadServlets(Document dom,
                           ClassLoader classLoader)
                    throws ClassNotFoundException,
                           NoSuchMethodException,
                           IllegalAccessException

Load the servlet definitions from an XML document.

Throws:

ClassNotFoundException

NoSuchMethodException

IllegalAccessException

loadServletClass

protected Class<? extends Servlet> loadServletClass(String className,
                                                    ClassLoader classLoader)
                                             throws ClassNotFoundException,
                                                    NoSuchMethodException,
                                                    IllegalAccessException

Load the servlet class. The class must implement the Servlet interface and have a public, no-argument contstructor

Parameters:

className - The name of the servlet class

classLoader - The classloader to use, or null to use the BASE core classloader

Returns:

An initialised factory

Throws:

ClassNotFoundException

NoSuchMethodException

IllegalAccessException