org.springframework.web.servlet.view.velocity
Class VelocityView

java.lang.Object
  org.springframework.context.support.ApplicationObjectSupport
      org.springframework.web.context.support.WebApplicationObjectSupport
          org.springframework.web.servlet.view.AbstractView
              org.springframework.web.servlet.view.AbstractUrlBasedView
                  org.springframework.web.servlet.view.velocity.VelocityView

All Implemented Interfaces:

ApplicationContextAware, BeanNameAware, View

public class VelocityView

extends AbstractUrlBasedView

View using the Velocity template engine. Based on code in the VelocityServlet shipped with Velocity.

Exposes the following JavaBean properties:

• url: the location of the Velocity template to be wrapped, relative to the Velocity resource loader path (see VelocityConfigurer).
• encoding (optional, default is determined by Velocity configuration): the encoding of the Velocity template file
• velocityFormatterAttribute (optional, default=null): the name of the VelocityFormatter helper object to expose in the Velocity context of this view, or null if not needed. VelocityFormatter is part of standard Velocity.
• dateToolAttribute (optional, default=null): the name of the DateTool helper object to expose in the Velocity context of this view, or null if not needed. DateTool is part of Velocity Tools 1.0.
• numberToolAttribute (optional, default=null): the name of the NumberTool helper object to expose in the Velocity context of this view, or null if not needed. NumberTool is part of Velocity Tools 1.1.
• cacheTemplate (optional, default=false): whether or not the Velocity template should be cached. It should normally be true in production, but setting this to false enables us to modify Velocity templates without restarting the application (similar to JSPs). Note that this is a minor optimization only, as Velocity itself caches templates in a modification-aware fashion.

Depends on a VelocityConfig object such as VelocityConfigurer being accessible in the current web application context, with any bean name. Alternatively, you can set the VelocityEngine object as bean property.

Version:

$Id: VelocityView.java,v 1.25 2004/03/18 02:46:15 trisberg Exp $

Author:

Rod Johnson, Juergen Hoeller

See Also:

VelocityConfig, VelocityConfigurer, AbstractUrlBasedView.setUrl(java.lang.String), setEncoding(java.lang.String), setVelocityEngine(org.apache.velocity.app.VelocityEngine), VelocityConfig, VelocityConfigurer

Field Summary

static int	DEFAULT_WRITER_POOL_SIZE
static int	OUTPUT_BUFFER_SIZE

Fields inherited from class org.springframework.context.support.ApplicationObjectSupport

logger

Constructor Summary

VelocityView()

Method Summary

protected void	exposeHelpers(org.apache.velocity.context.Context velocityContext, javax.servlet.http.HttpServletRequest request) Expose helpers unique to each rendering operation.
protected java.lang.String	getEncoding() Return the encoding for the Velocity template.
protected org.apache.velocity.Template	getTemplate() Retrieve the Velocity template.
protected org.apache.velocity.app.VelocityEngine	getVelocityEngine() Return the VelocityEngine used by this view.
protected void	initApplicationContext() Invoked on startup.
protected void	mergeTemplate(org.apache.velocity.Template template, org.apache.velocity.context.Context context, javax.servlet.http.HttpServletResponse response) Merge the template with the context.
protected void	renderMergedOutputModel(java.util.Map model, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response) Subclasses must implement this method to render the view.
void	setCacheTemplate(boolean cacheTemplate) Set whether the Velocity template should be cached.
void	setDateToolAttribute(java.lang.String dateToolAttribute) Set the name of the DateTool helper object to expose in the Velocity context of this view, or null if not needed.
void	setEncoding(java.lang.String encoding) Set the encoding of the Velocity template file.
void	setNumberToolAttribute(java.lang.String numberToolAttribute) Set the name of the NumberTool helper object to expose in the Velocity context of this view, or null if not needed.
void	setVelocityEngine(org.apache.velocity.app.VelocityEngine velocityEngine) Set the VelocityEngine to be used by this view.
void	setVelocityFormatterAttribute(java.lang.String velocityFormatterAttribute) Set the name of the VelocityFormatter helper object to expose in the Velocity context of this view, or null if not needed.

Methods inherited from class org.springframework.web.servlet.view.AbstractUrlBasedView

getUrl, setUrl

Methods inherited from class org.springframework.web.servlet.view.AbstractView

addStaticAttribute, getBeanName, getContentType, getStaticAttributes, render, setAttributes, setAttributesCSV, setAttributesMap, setBeanName, setContentType, setRequestContextAttribute

Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport

getServletContext, getTempDir, getWebApplicationContext, requiredContextClass

Methods inherited from class org.springframework.context.support.ApplicationObjectSupport

getApplicationContext, getMessageSourceAccessor, setApplicationContext

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WRITER_POOL_SIZE

public static final int DEFAULT_WRITER_POOL_SIZE

See Also:

Constant Field Values

OUTPUT_BUFFER_SIZE

public static final int OUTPUT_BUFFER_SIZE

See Also:

Constant Field Values

Constructor Detail

VelocityView

public VelocityView()

Method Detail

setEncoding

public void setEncoding(java.lang.String encoding)

Set the encoding of the Velocity template file. Default is determined by the VelocityEngine: "ISO-8859-1" if not specified otherwise.

Specify the encoding in the VelocityEngine rather than per template if all your templates share a common encoding.

getEncoding

protected java.lang.String getEncoding()

Return the encoding for the Velocity template.

setVelocityFormatterAttribute

public void setVelocityFormatterAttribute(java.lang.String velocityFormatterAttribute)

Set the name of the VelocityFormatter helper object to expose in the Velocity context of this view, or null if not needed. VelocityFormatter is part of the standard Velocity distribution.

See Also:

VelocityFormatter

setDateToolAttribute

public void setDateToolAttribute(java.lang.String dateToolAttribute)

Set the name of the DateTool helper object to expose in the Velocity context of this view, or null if not needed. DateTool is part of Velocity Tools 1.0.

See Also:

DateTool

setNumberToolAttribute

public void setNumberToolAttribute(java.lang.String numberToolAttribute)

Set the name of the NumberTool helper object to expose in the Velocity context of this view, or null if not needed. NumberTool is part of Velocity Tools 1.1.

See Also:

NumberTool

setCacheTemplate

public void setCacheTemplate(boolean cacheTemplate)

Set whether the Velocity template should be cached. Default is false. It should normally be true in production, but setting this to false enables us to modify Velocity templates without restarting the application (similar to JSPs).

Note that this is a minor optimization only, as Velocity itself caches templates in a modification-aware fashion.

setVelocityEngine

public void setVelocityEngine(org.apache.velocity.app.VelocityEngine velocityEngine)

Set the VelocityEngine to be used by this view. If this is not set, the default lookup will occur: A single VelocityConfig is expected in the current web application context, with any bean name.

See Also:

VelocityConfig

getVelocityEngine

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

Return the VelocityEngine used by this view.

initApplicationContext

protected void initApplicationContext()
                               throws BeansException

Invoked on startup. Looks for a single VelocityConfig bean to find the relevant VelocityEngine for this factory.

Overrides:

initApplicationContext in class AbstractUrlBasedView

Throws:

BeansException

renderMergedOutputModel

protected void renderMergedOutputModel(java.util.Map model,
                                       javax.servlet.http.HttpServletRequest request,
                                       javax.servlet.http.HttpServletResponse response)
                                throws java.lang.Exception

Description copied from class: AbstractView

Subclasses must implement this method to render the view.

The first take will be preparing the request: This may include setting the model elements as request attributes, e.g. in the case of a JSP view.

Specified by:

renderMergedOutputModel in class AbstractView

Parameters:

model - combined output Map, with dynamic values taking precedence over static attributes

request - current HTTP request

response - current HTTP response

Throws:

java.lang.Exception - if rendering failed

getTemplate

protected org.apache.velocity.Template getTemplate()
                                            throws java.lang.Exception

Retrieve the Velocity template.

Returns:

the Velocity template to process

Throws:

java.lang.Exception - if thrown by Velocity

exposeHelpers

protected void exposeHelpers(org.apache.velocity.context.Context velocityContext,
                             javax.servlet.http.HttpServletRequest request)
                      throws java.lang.Exception

Expose helpers unique to each rendering operation. This is necessary so that different rendering operations can't overwrite each other's formats etc.

Called by renderMergedOutputModel. The default implementations is empty. This method can be overridden to add custom helpers to the Velocity context.

Parameters:

velocityContext - Velocity context that will be passed to the template at merge time

request - current HTTP request

Throws:

java.lang.Exception - if there's a fatal error while we're adding information to the context

See Also:

renderMergedOutputModel(java.util.Map, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

mergeTemplate

protected void mergeTemplate(org.apache.velocity.Template template,
                             org.apache.velocity.context.Context context,
                             javax.servlet.http.HttpServletResponse response)
                      throws java.lang.Exception

Merge the template with the context. Can be overridden to customize the behavior.

Parameters:

template - the template to merge

context - the Velocity context

response - servlet response (use this to get the OutputStream or Writer)

Throws:

java.lang.Exception

See Also:

Template.merge(org.apache.velocity.context.Context, java.io.Writer)