org.itsnat.core

Interface ItsNatVariableResolver

public interface ItsNatVariableResolver

Used to locate/replace text marks (variables) inside text based nodes (text nodes, comments, attribute values etc) without knowing the exact position in the DOM tree.

The variable syntax follows the JSP Expression Language notation: ${name}.

Author:

Jose Maria Arranz Santamaria

See Also:

ItsNatServletRequest.createItsNatVariableResolver(), ItsNatDocument.createItsNatVariableResolver(), ItsNatDocument.createItsNatVariableResolver(boolean), ItsNatSession.createItsNatVariableResolver(), ItsNatServletContext.createItsNatVariableResolver()

Method Summary

Methods

Modifier and Type	Method and Description
ItsNatVariableResolver	createItsNatVariableResolver() Creates a variable resolver as a child of this resolver (bound to this resolver).
Object	getLocalVariable(String name) Returns the value associated to the specified name, only the local registry of this resolver is searched.
Object	getVariable(String name) Returns the value associated to the specified name.
void	introspect(String refName, Object obj) Introspect the specified object registering all JavaBeans properties as local variables prefixed with the specified reference name.
boolean	isDisconnected() Informs whether this variable resolver is disconnected (does not have a parent).
Object	removeLocalVariable(String name) Unregisters the variable with the specified name from the local registry of this resolver.
boolean	resolve(Node node) Iterates recursively into the DOM subtree resolving (replacing) if possible any variable found with the format ${name} into element attributes and text based nodes.
String	resolve(String str) Locates and replaces any variable declaration with format ${name} contained into the specified string with the variable value converted to string (Object.toString()).
Object	setLocalVariable(String name, Object value) Registers the specified variable name and value into the local registry of this resolver.

Method Detail

isDisconnected

boolean isDisconnected()

Informs whether this variable resolver is disconnected (does not have a parent). Only local variables are used.

Returns:

true if this variable resolver is disconnected.

createItsNatVariableResolver

ItsNatVariableResolver createItsNatVariableResolver()

Creates a variable resolver as a child of this resolver (bound to this resolver).

Returns:

a variable resolver bound to this resolver.

getLocalVariable

Object getLocalVariable(String name)

Returns the value associated to the specified name, only the local registry of this resolver is searched.

Parameters:

name - the name to search for.

Returns:

the value associated to the specified name or null if none is found.

See Also:

setLocalVariable(String,Object), removeLocalVariable(String)

setLocalVariable

Object setLocalVariable(String name,
                      Object value)

Registers the specified variable name and value into the local registry of this resolver.

Parameters:

name - the variable name.

value - the variable value.

Returns:

the old value or null if not found.

See Also:

getLocalVariable(String)

removeLocalVariable

Object removeLocalVariable(String name)

Unregisters the variable with the specified name from the local registry of this resolver.

Parameters:

name - the variable name.

Returns:

the variable value or null if not found.

See Also:

getLocalVariable(String)

introspect

void introspect(String refName,
              Object obj)

Introspect the specified object registering all JavaBeans properties as local variables prefixed with the specified reference name.

Current implementation uses jav.beans.Introspector.getBeanInfo(Class) to get all JavaBeans properties. The reference name and property name are used to build a qualified name using a dot as separator, this qualified name is used to register as variable (e.g. "person.firstName" where "person" is the reference name and "firstName" is a JavaBeans property).

Parameters:

refName - reference name used to qualify JavaBeans properties. If null or empty no prefix is added to property names.

obj - reference to the object value to introspect and register its JavaBeans properties.

getVariable

Object getVariable(String name)

Returns the value associated to the specified name.

First of all the local registry is searched calling getLocalVariable(String). If this method returns null and this resolver is "disconnected" (was created calling ItsNatDocument.createItsNatVariableResolver(boolean) with parameter disconnected set to true) variable resolution ends returning null. If "connected" (variable resolver was created with any other factory method) the "owner" of this resolver is used:

If the variable resolver is a child of another variable resolver (was created with createItsNatVariableResolver()) then the method getVariable(String) of the parent is called to continue searching.

If the variable resolver was created with ItsNatServletContext.createItsNatVariableResolver() then the method ServletContext.getAttribute(String) is called to continue searching.

If the variable resolver was created with ItsNatSession.createItsNatVariableResolver() then the method ItsNatSession.getAttribute(String) is called to continue searching, if returns null then delegates to the method ServletContext.getAttribute(String).

If the variable resolver was created with ItsNatDocument.createItsNatVariableResolver() then the method ItsNatDocument.getAttribute(String) is called to continue searching, if returns null then delegates to the method ItsNatSession.getAttribute(String), if returns null then delegates to the method ServletContext.getAttribute(String).

Parameters:

name - the name to search for.

Returns:

the value associated to the specified name or null if none is found.

resolve

String resolve(String str)

Locates and replaces any variable declaration with format ${name} contained into the specified string with the variable value converted to string (Object.toString()).

To obtain the value the method getVariable(String) is called, if no variable is found the variable declaration is kept as is.

The same variable may be repeated.

Parameters:

str - the source string to resolve declared variables.

Returns:

the new string with replaced variables by values. If no variable was replaced (the original string is untouched) returns null.

See Also:

resolve(org.w3c.dom.Node)

resolve

boolean resolve(Node node)

Iterates recursively into the DOM subtree resolving (replacing) if possible any variable found with the format ${name} into element attributes and text based nodes.

The method resolve(String) is used to process element attributes and content of text based nodes.

Parameters:

node - the node to resolve.

Returns:

true if some variable was resolved (replaced).