pnuts.ext
Class ModuleBase

java.lang.Object
  pnuts.ext.ModuleBase

All Implemented Interfaces:

java.io.Serializable, Executable

Direct Known Subclasses:

init

public abstract class ModuleBase
extends java.lang.Object
implements Executable, java.io.Serializable

Base class of modules. This class provides convenient autloading functions and an error reporting function. Modules may (or may not) subclass this class.

See Also:

Serialized Form

Constructor Summary

ModuleBase()

Method Summary

protected void	autoload(java.lang.String[] functionNames, java.lang.String file, Context context) Registers an autoloaded script for functionNames.
protected void	autoloadClass(java.lang.String javaPackage, java.lang.String name, Context context) Registers an autoloaded Class object.
protected void	autoloadFunction(java.lang.String functionName, Context context) Registers an autoloaded class for functionName.
protected java.lang.Object	execute(Context context) Subclasses should override this method, instead of run(Context), to define the initialization process.
protected java.lang.String	getClassName(Package pkg, java.lang.String name) Makes a class name for the specified package and the symbol's name.
protected Package	getPackage(Context context)
protected java.lang.String	getPrefix() Defines the prefix of script class (resource) name.
protected java.lang.String[]	getRequiredModules() This method is supposed to be redefined in a subclass to define a set of modules that are required to implement this module.
protected java.lang.String[]	getSubModules() This method is supposed to be redefined in a subclass to define a set of modules that this module provides in the caller's context.
protected java.lang.Object	newInstance(java.lang.Class cls) This method is redefined in subclasses so that package private classes can be used.
java.lang.Object	run(Context context) Defines ERROR and EXPORTS, and then call execute(Context).

Methods inherited from class java.lang.Object

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

Constructor Detail

ModuleBase

public ModuleBase()

Method Detail

autoload

protected void autoload(java.lang.String[] functionNames,
                        java.lang.String file,
                        Context context)

Registers an autoloaded script for functionNames. Also, functionNames are automatically exported.

Parameters:

functionNames - the function names

file - a script file to be loaded when one of the functionNames is first resolved.

context - the context

autoloadFunction

protected void autoloadFunction(java.lang.String functionName,
                                Context context)

Registers an autoloaded class for functionName. Also, the functionName is automatically exported.

Parameters:

functionName - the function name

context - the context

autoloadClass

protected void autoloadClass(java.lang.String javaPackage,
                             java.lang.String name,
                             Context context)

Registers an autoloaded Class object.

Parameters:

javaPackage - Java package name, e.g. "java.util"

name - short Class name, e.g. "HashMap"

context - the context

getPrefix

protected java.lang.String getPrefix()

Defines the prefix of script class (resource) name. This method is overriden by subclasses.

getPackage

protected Package getPackage(Context context)

newInstance

protected java.lang.Object newInstance(java.lang.Class cls)
                                throws java.lang.IllegalAccessException,
                                       java.lang.InstantiationException

This method is redefined in subclasses so that package private classes can be used.

Parameters:

cls - the class to be instantiated

Returns:

an instance of the class

Throws:

java.lang.IllegalAccessException

java.lang.InstantiationException

getClassName

protected java.lang.String getClassName(Package pkg,
                                        java.lang.String name)

Makes a class name for the specified package and the symbol's name.

Parameters:

pkg - the package

name - the symbol

Returns:

the name of the class

run

public java.lang.Object run(Context context)

Defines ERROR and EXPORTS, and then call execute(Context).

Specified by:

run in interface Executable

Parameters:

context - the context

Returns:

the result of the execution

execute

protected java.lang.Object execute(Context context)

Subclasses should override this method, instead of run(Context), to define the initialization process. If neither getSubModules() nor getRequiredModules() are redefined to return non-null value, execute() method should be implemented as the following steps. 1. Call context.usePackage() to use the modules that this module provides 2. Call context.clearPackages() 3. Call context.usePackage() to use the module that this module requires 4. Define symbols (functions)

Parameters:

context - the context

getRequiredModules

protected java.lang.String[] getRequiredModules()

This method is supposed to be redefined in a subclass to define a set of modules that are required to implement this module. If this method returns an array of module names (non-null), Context.clearPackages() is called, then the modules are used()'d, before calling execute() method.

getSubModules

protected java.lang.String[] getSubModules()

This method is supposed to be redefined in a subclass to define a set of modules that this module provides in the caller's context. If this method returns an array of module names (non-null), they are use()'d, then Context.clearPackages() is called, before calling execute() method.