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:

ChainedContext, 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

private javax.servlet.ServletContext	application
private javax.servlet.http.HttpServletRequest	request
private javax.servlet.http.HttpServletResponse	response
private java.lang.String	toolboxKey
private org.apache.velocity.app.VelocityEngine	velocity

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

CATCH_EXCEPTIONS_KEY, CONTEXT_KEY, ENGINE_KEY, LOCALE_KEY, LOG_KEY, PATH_KEY

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

APPLICATION, DEFAULT_TOOLBOX_KEY, REQUEST, RESPONSE, SERVLET_CONTEXT_KEY, SESSION

Constructor Summary

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

Method Summary

protected void	addToolboxesUnderKey(java.lang.String toolboxKey)
boolean	containsKey(java.lang.String key) Indicates whether the specified key is in the context.
java.lang.Object	get(java.lang.String key) Looks up and returns the object with the specified key.
java.lang.Object	getAttribute(java.lang.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() Returns the current servlet request.
javax.servlet.http.HttpServletResponse	getResponse() Returns the current servlet response.
protected java.lang.Object	getServletApi(java.lang.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() Returns the servlet context.
javax.servlet.http.HttpSession	getSession() Returns the current session, if any.
protected java.util.List<Toolbox>	getToolboxes()
protected java.lang.Object	getToolVar(java.lang.String key) Finds the automatically provided values, either configured tools or servlet API objects (request, response, etc).
protected java.lang.Object	getUserVar(java.lang.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() Returns a reference to the Velocity context (this object).
org.apache.velocity.app.VelocityEngine	getVelocityEngine() Returns a reference to the VelocityEngine.
protected void	putToolProperties()
protected void	setToolboxKey(java.lang.String key)

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

addToolbox, containsKey, 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

Field Detail

request

private final javax.servlet.http.HttpServletRequest request

response

private final javax.servlet.http.HttpServletResponse response

application

private final javax.servlet.ServletContext application

velocity

private final org.apache.velocity.app.VelocityEngine velocity

toolboxKey

private java.lang.String toolboxKey

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(java.lang.String key)

putToolProperties

protected void putToolProperties()

getToolboxes

protected java.util.List<Toolbox> getToolboxes()

Overrides:

getToolboxes in class ToolContext

addToolboxesUnderKey

protected void addToolboxesUnderKey(java.lang.String toolboxKey)

get

public java.lang.Object get(java.lang.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 java.lang.Object getUserVar(java.lang.String key)

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

See Also:

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

getToolVar

protected java.lang.Object getToolVar(java.lang.String key)

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

See Also:

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

getServletApi

protected java.lang.Object getServletApi(java.lang.String key)

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

getAttribute

public java.lang.Object getAttribute(java.lang.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

Since:

VelocityTools 1.1

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

getSession

public javax.servlet.http.HttpSession getSession()

Returns the current session, if any.

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

getVelocityEngine

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

Returns a reference to the VelocityEngine.

Specified by:

getVelocityEngine in interface ViewContext

containsKey

public boolean containsKey(java.lang.String key)

Indicates whether the specified key is in the context.

Parameters:

key - The key to look for.

Returns:

Whether the key is in the context.