org.apache.commons.workflow
Interface Descriptor

All Known Implementing Classes:

BaseDescriptor

public interface Descriptor

A Descriptor is a description of the mechanism by which an arbitrary Java object (typically a JavaBean) is referenced. The following reference methods are supported, and are processed in the order specified here:

• If the xpath property is set, it is used as an XPath expression identifying the requested object.
• If the name (and optional scope) properties are specified, they are used to select a particular named bean, optionally found in a particular named scope.
• If none of the conditions above are satisfied, the top object on the evaluation stack of our current Context is consumed.

Version:

$Revision: 155475 $ $Date: 2005-02-26 13:31:11 +0000 (Sat, 26 Feb 2005) $

Author:

Craig R. McClanahan

Method Summary

Object	get(Context context) Return the value specified by this Descriptor from the specified Context.
String	getName() Return the name of the Java object (in some scope) referenced by this Descriptor.
String	getScope() Return the scope of the Java object referenced by this Descriptor.
Class	getType() Return the optional Java class expected by this Descriptor.
String	getXpath() Return the XPath expression used to access the Java object referenced by this Descriptor.
boolean	positive(Context context) Call get() to retrieve the value specified by this Descriptor, and then return true if this value represents a positive result; otherwise return false.
void	put(Context context, Object value) Store the value into the destination specified by this Descriptor in the specified Context, replacing any existing value.
void	remove(Context context) Remove any existing value associated with this Descriptor from the specified Context.
void	setName(String name) Set the name of the Java object (in some scope) referenced by this Descriptor.
void	setScope(String scope) Set the scope of the Java object referenced by this Descriptor.
void	setType(Class type) Set the optional Java class expected by this Descriptor.
void	setXpath(String xpath) Set the XPath expression used to access the Java object referenced by this Descriptor.

Method Detail

getName

String getName()

Return the name of the Java object (in some scope) referenced by this Descriptor.

setName

void setName(String name)

Set the name of the Java object (in some scope) referenced by this Descriptor.

Parameters:

name - The new object name

getScope

String getScope()

Return the scope of the Java object referenced by this Descriptor.

setScope

void setScope(String scope)

Set the scope of the Java object referenced by this Descriptor.

Parameters:

scope - The new scope name

getType

Class getType()

Return the optional Java class expected by this Descriptor.

setType

void setType(Class type)

Set the optional Java class expected by this Descriptor.

Parameters:

type - The new expected type

getXpath

String getXpath()

Return the XPath expression used to access the Java object referenced by this Descriptor.

setXpath

void setXpath(String xpath)

Set the XPath expression used to access the Java object referenced by this Descriptor.

Parameters:

xpath - The new XPath expression

get

Object get(Context context)

Return the value specified by this Descriptor from the specified Context. If there is no such value, return null.

Parameters:

context - Context from which to retrieve this value

positive

boolean positive(Context context)

Call get() to retrieve the value specified by this Descriptor, and then return true if this value represents a positive result; otherwise return false.

Parameters:

context - Context from which to retrieve this value

put

void put(Context context,
         Object value)

Store the value into the destination specified by this Descriptor in the specified Context, replacing any existing value.

Parameters:

context - Context into which to store this value

value - Object value to be stored

remove

void remove(Context context)

Remove any existing value associated with this Descriptor from the specified Context.

Parameters:

context - Context from which to remove this value.