net.sf.saxon.trans
Class DynamicLoader

java.lang.Object
  net.sf.saxon.trans.DynamicLoader

Direct Known Subclasses:

DynamicLoaderPE

public class DynamicLoader
extends Object

Utility class used to perform dynamic loading of user-hook implementations

Field Summary

protected HashMap<String,Class>

knownClasses

Constructor Summary

DynamicLoader()

Method Summary

Class	getClass(String className, PrintStream traceOut, ClassLoader classLoader) Load a class using the class name provided.
ClassLoader	getClassLoader() Get the ClassLoader supplied using the method setClassLoader(java.lang.ClassLoader).
Object	getInstance(String className, ClassLoader classLoader) Instantiate a class using the class name provided.
Object	getInstance(String className, PrintStream traceOut, ClassLoader classLoader) Instantiate a class using the class name provided, with the option of tracing Note that the method does not check that the object is of the right class.
protected void	registerKnownClasses() Register classes that might be dynamically loaded even though they are contained within Saxon itself.
void	setClassLoader(ClassLoader loader) Set a ClassLoader to be used when loading external classes.

Methods inherited from class java.lang.Object

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

Field Detail

knownClasses

protected HashMap<String,Class> knownClasses

Constructor Detail

DynamicLoader

public DynamicLoader()

Method Detail

registerKnownClasses

protected void registerKnownClasses()

Register classes that might be dynamically loaded even though they are contained within Saxon itself. This typically occurs for default implementations of classes that can be substituted or subclassed by the user.

setClassLoader

public void setClassLoader(ClassLoader loader)

Set a ClassLoader to be used when loading external classes. Examples of classes that are loaded include SAX parsers, localization modules for formatting numbers and dates, extension functions, external object models. In an environment such as Eclipse that uses its own ClassLoader, this ClassLoader should be nominated to ensure that any class loaded by Saxon is identical to a class of the same name loaded by the external environment.

Parameters:

loader - the ClassLoader to be used in this configuration

getClassLoader

public ClassLoader getClassLoader()

Get the ClassLoader supplied using the method setClassLoader(java.lang.ClassLoader). If none has been supplied, return null.

Returns:

the ClassLoader used in this configuration

getClass

public Class getClass(String className,
                      PrintStream traceOut,
                      ClassLoader classLoader)
               throws XPathException

Load a class using the class name provided. Note that the method does not check that the object is of the right class.

This method is intended for internal use only.

Parameters:

className - A string containing the name of the class, for example "com.microstar.sax.LarkDriver"

traceOut - if diagnostic tracing is required, the destination for the output; otherwise null

classLoader - The ClassLoader to be used to load the class. If this is null, then the classLoader used will be the first one available of: the classLoader registered with the Configuration using setClassLoader(java.lang.ClassLoader); the context class loader for the current thread; or failing that, the class loader invoked implicitly by a call of Class.forName() (which is the ClassLoader that was used to load the Configuration object itself).

Returns:

an instance of the class named, or null if it is not loadable.

Throws:

XPathException - if the class cannot be loaded.

getInstance

public Object getInstance(String className,
                          ClassLoader classLoader)
                   throws XPathException

Instantiate a class using the class name provided. Note that the method does not check that the object is of the right class.

This method is intended for internal use only.

Parameters:

className - A string containing the name of the class, for example "com.microstar.sax.LarkDriver"

classLoader - The ClassLoader to be used to load the class. If this is null, then the classLoader used will be the first one available of: the classLoader registered with the Configuration using setClassLoader(java.lang.ClassLoader); the context class loader for the current thread; or failing that, the class loader invoked implicitly by a call of Class.forName() (which is the ClassLoader that was used to load the Configuration object itself).

Returns:

an instance of the class named, or null if it is not loadable.

Throws:

XPathException - if the class cannot be loaded.

getInstance

public Object getInstance(String className,
                          PrintStream traceOut,
                          ClassLoader classLoader)
                   throws XPathException

Instantiate a class using the class name provided, with the option of tracing Note that the method does not check that the object is of the right class.

This method is intended for internal use only.

Parameters:

className - A string containing the name of the class, for example "com.microstar.sax.LarkDriver"

traceOut - if attempts to load classes are to be traced, then the destination for the trace output; otherwise null

classLoader - The ClassLoader to be used to load the class. If this is null, then the classLoader used will be the first one available of: the classLoader registered with the Configuration using setClassLoader(java.lang.ClassLoader); the context class loader for the current thread; or failing that, the class loader invoked implicitly by a call of Class.forName() (which is the ClassLoader that was used to load the Configuration object itself).

Returns:

an instance of the class named, or null if it is not loadable.

Throws:

XPathException - if the class cannot be loaded.