org.apache.velocity.tools.view.context
Class ChainedContext

java.lang.Object
  |
  +--org.apache.velocity.context.InternalContextBase
        |
        +--org.apache.velocity.context.AbstractContext
              |
              +--org.apache.velocity.VelocityContext
                    |
                    +--org.apache.velocity.tools.view.context.ChainedContext

All Implemented Interfaces:

java.lang.Cloneable, org.apache.velocity.context.Context, org.apache.velocity.context.InternalEventContext, org.apache.velocity.context.InternalHousekeepingContext, java.io.Serializable, ViewContext

public class ChainedContext

extends org.apache.velocity.VelocityContext

implements ViewContext

Velocity context implementation specific to the Servlet environment.

It provides the following special features:

• puts the request, response, session, and servlet context objects into the Velocity context for direct access, and keeps them read-only
• supports a read-only toolbox of view tools
• auto-searches servlet request attributes, session attributes and servlet context attribues for objects

The internalGet(String key) method implements the following search order for objects:

1. toolbox
2. servlet request, servlet response, servlet session, servlet context
3. local hashtable of objects (traditional use)
4. servlet request attribues, servlet session attribute, servlet context attributes

The purpose of this class is to make it easy for web designer to work with Java servlet based web applications. They do not need to be concerned with the concepts of request, session or application attributes and the lifetime of objects in these scopes.

Note that the put() method always puts objects into the local hashtable.

Version:

$Id: ChainedContext.java,v 1.3 2003/05/28 00:17:16 nbubna Exp $

Author:

Geir Magnusson Jr., Gabe Sidler

See Also:

Serialized Form

Field Summary

private javax.servlet.ServletContext	application A local reference to the servlet context.
static java.lang.String	APPLICATION Key to the servlet context object.
private javax.servlet.http.HttpServletRequest	request A local reference to the current servlet request.
static java.lang.String	REQUEST Key to the HTTP request object.
private javax.servlet.http.HttpServletResponse	response A local reference to the current servlet response.
static java.lang.String	RESPONSE Key to the HTTP response object.
private javax.servlet.http.HttpSession	session A local reference to the servlet session.
static java.lang.String	SESSION Key to the HTTP session object.
private ToolboxContext	toolboxContext The toolbox.

Fields inherited from class org.apache.velocity.VelocityContext

Fields inherited from class org.apache.velocity.context.AbstractContext

Constructor Summary

ChainedContext(org.apache.velocity.context.Context ctx, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.ServletContext application)
Default constructor.

Method Summary

javax.servlet.http.HttpServletRequest	getRequest() Returns the current servlet request.
javax.servlet.http.HttpServletResponse	getResponse() Returns the current servlet response.
javax.servlet.ServletContext	getServletContext() Returns the servlet context.
org.apache.velocity.context.Context	getVelocityContext() Returns a reference to the Velocity context (this object).
java.lang.Object	internalGet(java.lang.String key) Looks up and returns the object with the specified key.
void	setToolbox(ToolboxContext box) Sets the toolbox of view tools.

Methods inherited from class org.apache.velocity.VelocityContext

clone, internalContainsKey, internalGetKeys, internalPut, internalRemove

Methods inherited from class org.apache.velocity.context.AbstractContext

attachEventCartridge, containsKey, get, getChainedContext, getCurrentResource, getCurrentTemplateName, getEventCartridge, getKeys, getTemplateNameStack, icacheGet, icachePut, popCurrentTemplateName, pushCurrentTemplateName, put, remove, setCurrentResource

Methods inherited from class java.lang.Object

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

Field Detail

request

private javax.servlet.http.HttpServletRequest request

A local reference to the current servlet request.

response

private javax.servlet.http.HttpServletResponse response

A local reference to the current servlet response.

session

private javax.servlet.http.HttpSession session

A local reference to the servlet session.

application

private javax.servlet.ServletContext application

A local reference to the servlet context.

toolboxContext

private ToolboxContext toolboxContext

The toolbox.

REQUEST

public static final java.lang.String REQUEST

Key to the HTTP request object.

See Also:

Constant Field Values

RESPONSE

public static final java.lang.String RESPONSE

Key to the HTTP response object.

See Also:

Constant Field Values

SESSION

public static final java.lang.String SESSION

Key to the HTTP session object.

See Also:

Constant Field Values

APPLICATION

public static final java.lang.String APPLICATION

Key to the servlet context object.

See Also:

Constant Field Values

Constructor Detail

ChainedContext

public ChainedContext(org.apache.velocity.context.Context ctx,
                      javax.servlet.http.HttpServletRequest request,
                      javax.servlet.http.HttpServletResponse response,
                      javax.servlet.ServletContext application)

Default constructor.

Method Detail

setToolbox

public void setToolbox(ToolboxContext box)

Sets the toolbox of view tools.

Parameters:

box - toolbox of view tools

internalGet

public java.lang.Object internalGet(java.lang.String key)

Looks up and returns the object with the specified key.

See the class documentation for more details.

Overrides:

internalGet in class org.apache.velocity.VelocityContext

Parameters:

key - the key of the object requested

Returns:

the requested object or null if not found

getRequest

public javax.servlet.http.HttpServletRequest getRequest()

Returns the current servlet request.

Specified by:

getRequest in interface ViewContext

getResponse

public javax.servlet.http.HttpServletResponse getResponse()

Returns the current servlet response.

Specified by:

getResponse in interface ViewContext

getServletContext

public javax.servlet.ServletContext getServletContext()

Returns the servlet context.

Specified by:

getServletContext in interface ViewContext

getVelocityContext

public org.apache.velocity.context.Context getVelocityContext()

Returns a reference to the Velocity context (this object).

Specified by:

getVelocityContext in interface ViewContext