org.apache.velocity.tools.view

Class ViewToolContext

java.lang.Object

org.apache.velocity.tools.ToolContext

org.apache.velocity.tools.view.ViewToolContext

All Implemented Interfaces:

org.apache.velocity.context.Context, ViewContext

Direct Known Subclasses:

JspToolContext

public class ViewToolContext
extends ToolContext
implements ViewContext

ToolContext 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 get(String key) method implements the following search order for objects:

1. tool in a request scoped toolbox
2. tool in a session scoped toolbox
3. tool in a application scoped toolbox
4. request, response, session, or servlet context
5. object in the local map of objects (traditional use)
6. request attributes, session attributes, 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 map and does not allow tools or servlet classes to be overridden.

Version:

$Id: ViewContext.java 514727 2007-03-05 16:49:03Z nbubna $

Author:

Geir Magnusson Jr., Gabe Sidler, Nathan Bubna

Field Summary

Fields inherited from class org.apache.velocity.tools.ToolContext

CATCH_EXCEPTIONS_KEY, CONTEXT_KEY, ENGINE_KEY, LOCALE_KEY, LOG_KEY, PATH_KEY, TOOLKEY_KEY

Fields inherited from interface org.apache.velocity.tools.view.ViewContext

APPLICATION, DEFAULT_TOOLBOX_KEY, REQUEST, RESPONSE, SERVLET_CONTEXT_KEY, SESSION

Constructor Summary

Constructors

Constructor and Description
ViewToolContext(org.apache.velocity.app.VelocityEngine velocity, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, javax.servlet.ServletContext application)

Method Summary

Modifier and Type	Method and Description
protected void	addToolboxesUnderKey(String toolboxKey)
boolean	containsKey(String key) Indicates whether the specified key is in the context.
Object	get(String key) Looks up and returns the object with the specified key.
Object	getAttribute(String key) Searches for the named attribute in request, session (if valid), and application scope(s) in order and returns the value associated or null.
javax.servlet.http.HttpServletRequest	getRequest()
javax.servlet.http.HttpServletResponse	getResponse()
protected Object	getServletApi(String key) Returns the current matching servlet request, response, session, or servlet context instance, or null if the key matches none of those keys.
javax.servlet.ServletContext	getServletContext()
javax.servlet.http.HttpSession	getSession()
protected List<Toolbox>	getToolboxes()
protected Object	getToolVar(String key) Finds the automatically provided values, either configured tools or servlet API objects (request, response, etc).
protected Object	getUserVar(String key) Finds "user" set values, either in the local context or in the scoped attributes if none is in the local context.
org.apache.velocity.context.Context	getVelocityContext()
org.apache.velocity.app.VelocityEngine	getVelocityEngine()
protected void	putToolProperties()
protected void	setToolboxKey(String key)

Methods inherited from class org.apache.velocity.tools.ToolContext

addToolbox, findTool, getKeys, getToolbox, getToolClassMap, getToolProperties, getUserCanOverwriteTools, internalGet, keySet, put, putAll, putToolProperties, putToolProperty, putVelocityEngine, remove, setUserCanOverwriteTools

Methods inherited from class java.lang.Object

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

Constructor Detail

ViewToolContext

public ViewToolContext(org.apache.velocity.app.VelocityEngine velocity,
                       javax.servlet.http.HttpServletRequest request,
                       javax.servlet.http.HttpServletResponse response,
                       javax.servlet.ServletContext application)

Method Detail

setToolboxKey

protected void setToolboxKey(String key)

putToolProperties

protected void putToolProperties()

getToolboxes

protected List<Toolbox> getToolboxes()

Overrides:

getToolboxes in class ToolContext

addToolboxesUnderKey

protected void addToolboxesUnderKey(String toolboxKey)

get

public Object get(String key)

Looks up and returns the object with the specified key.

See the class documentation for more details.

Specified by:

get in interface org.apache.velocity.context.Context

Overrides:

get in class ToolContext

Parameters:

key - the key of the object requested

Returns:

the requested object or null if not found

See Also:

ToolContext.setUserCanOverwriteTools(boolean), getUserVar(java.lang.String), getToolVar(java.lang.String)

getUserVar

protected Object getUserVar(String key)

Finds "user" set values, either in the local context or in the scoped attributes if none is in the local context.

Parameters:

key - attribute name

Returns:

found value or null

See Also:

ToolContext.internalGet(java.lang.String), getAttribute(java.lang.String)

getToolVar

protected Object getToolVar(String key)

Finds the automatically provided values, either configured tools or servlet API objects (request, response, etc).

Parameters:

key - attribute key

Returns:

found configured value or null

See Also:

ToolContext.findTool(java.lang.String), getServletApi(java.lang.String)

getServletApi

protected Object getServletApi(String key)

Returns the current matching servlet request, response, session, or servlet context instance, or null if the key matches none of those keys.

Parameters:

key - attribute key

Returns:

found value or null

getAttribute

public Object getAttribute(String key)

Searches for the named attribute in request, session (if valid), and application scope(s) in order and returns the value associated or null.

Specified by:

getAttribute in interface ViewContext

Parameters:

key - attribute key

Returns:

found value or null

Since:

VelocityTools 1.1

getRequest

public javax.servlet.http.HttpServletRequest getRequest()

Specified by:

getRequest in interface ViewContext

Returns:

the current servlet request.

getResponse

public javax.servlet.http.HttpServletResponse getResponse()

Specified by:

getResponse in interface ViewContext

Returns:

the current servlet response.

getSession

public javax.servlet.http.HttpSession getSession()

Returns:

the current session, if any.

getServletContext

public javax.servlet.ServletContext getServletContext()

Specified by:

getServletContext in interface ViewContext

Returns:

the servlet context.

getVelocityContext

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

Specified by:

getVelocityContext in interface ViewContext

Returns:

a reference to the Velocity context (this object).

getVelocityEngine

public org.apache.velocity.app.VelocityEngine getVelocityEngine()

Specified by:

getVelocityEngine in interface ViewContext

Returns:

a reference to the VelocityEngine.

containsKey

public boolean containsKey(String key)

Indicates whether the specified key is in the context.

Specified by:

containsKey in interface org.apache.velocity.context.Context

Overrides:

containsKey in class ToolContext

Parameters:

key - The key to look for.

Returns:

Whether the key is in the context.