Spring Framework

org.springframework.web.servlet.view
Class AbstractView

java.lang.Object
  extended by org.springframework.context.support.ApplicationObjectSupport
      extended by org.springframework.web.context.support.WebApplicationObjectSupport
          extended by org.springframework.web.servlet.view.AbstractView
All Implemented Interfaces:
Aware, BeanNameAware, ApplicationContextAware, ServletContextAware, View
Direct Known Subclasses:
AbstractExcelView, AbstractFeedView, AbstractJExcelView, AbstractPdfView, AbstractUrlBasedView, AbstractXsltView, MappingJackson2JsonView, MappingJacksonJsonView, MarshallingView

public abstract class AbstractView
extends WebApplicationObjectSupport
implements View, BeanNameAware

Abstract base class for View implementations. Subclasses should be JavaBeans, to allow for convenient configuration as Spring-managed bean instances.

Provides support for static attributes, to be made available to the view, with a variety of ways to specify them. Static attributes will be merged with the given dynamic attributes (the model that the controller returned) for each render operation.

Extends WebApplicationObjectSupport, which will be helpful to some views. Subclasses just need to implement the actual rendering.

Author:
Rod Johnson, Juergen Hoeller
See Also:
setAttributes(java.util.Properties), setAttributesMap(java.util.Map), renderMergedOutputModel(java.util.Map, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

Field Summary
static java.lang.String DEFAULT_CONTENT_TYPE
          Default content type.
 
Fields inherited from class org.springframework.context.support.ApplicationObjectSupport
logger
 
Fields inherited from interface org.springframework.web.servlet.View
PATH_VARIABLES, RESPONSE_STATUS_ATTRIBUTE
 
Constructor Summary
AbstractView()
           
 
Method Summary
 void addStaticAttribute(java.lang.String name, java.lang.Object value)
          Add static data to this view, exposed in each view.
protected  java.util.Map<java.lang.String,java.lang.Object> createMergedOutputModel(java.util.Map<java.lang.String,?> model, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
          Creates a combined output Map (never null) that includes dynamic values and static attributes.
protected  RequestContext createRequestContext(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response, java.util.Map<java.lang.String,java.lang.Object> model)
          Create a RequestContext to expose under the specified attribute name.
protected  java.io.ByteArrayOutputStream createTemporaryOutputStream()
          Create a temporary OutputStream for this view.
protected  void exposeModelAsRequestAttributes(java.util.Map<java.lang.String,java.lang.Object> model, javax.servlet.http.HttpServletRequest request)
          Expose the model objects in the given map as request attributes.
protected  boolean generatesDownloadContent()
          Return whether this view generates download content (typically binary content like PDF or Excel files).
 java.util.Map<java.lang.String,java.lang.Object> getAttributesMap()
          Allow Map access to the static attributes of this view, with the option to add or override specific entries.
 java.lang.String getBeanName()
          Return the view's name.
 java.lang.String getContentType()
          Return the content type for this view.
 java.lang.String getRequestContextAttribute()
          Return the name of the RequestContext attribute, if any.
 java.util.Map<java.lang.String,java.lang.Object> getStaticAttributes()
          Return the static attributes for this view.
 boolean isExposePathVariables()
          Returns the value of the flag indicating whether path variables should be added to the model or not.
protected  void prepareResponse(javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
          Prepare the given response for rendering.
 void render(java.util.Map<java.lang.String,?> model, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
          Prepares the view given the specified model, merging it with static attributes and a RequestContext attribute, if necessary.
protected abstract  void renderMergedOutputModel(java.util.Map<java.lang.String,java.lang.Object> model, javax.servlet.http.HttpServletRequest request, javax.servlet.http.HttpServletResponse response)
          Subclasses must implement this method to actually render the view.
 void setAttributes(java.util.Properties attributes)
          Set static attributes for this view from a java.util.Properties object.
 void setAttributesCSV(java.lang.String propString)
          Set static attributes as a CSV string.
 void setAttributesMap(java.util.Map<java.lang.String,?> attributes)
          Set static attributes for this view from a Map.
 void setBeanName(java.lang.String beanName)
          Set the view's name.
 void setContentType(java.lang.String contentType)
          Set the content type for this view.
 void setExposePathVariables(boolean exposePathVariables)
          Whether to add path variables in the model or not.
 void setRequestContextAttribute(java.lang.String requestContextAttribute)
          Set the name of the RequestContext attribute for this view.
 java.lang.String toString()
           
protected  void writeToResponse(javax.servlet.http.HttpServletResponse response, java.io.ByteArrayOutputStream baos)
          Write the given temporary OutputStream to the HTTP response.
 
Methods inherited from class org.springframework.web.context.support.WebApplicationObjectSupport
getServletContext, getTempDir, getWebApplicationContext, initApplicationContext, initServletContext, isContextRequired, setServletContext
 
Methods inherited from class org.springframework.context.support.ApplicationObjectSupport
getApplicationContext, getMessageSourceAccessor, initApplicationContext, requiredContextClass, setApplicationContext
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Field Detail

DEFAULT_CONTENT_TYPE

public static final java.lang.String DEFAULT_CONTENT_TYPE
Default content type. Overridable as bean property.

See Also:
Constant Field Values
Constructor Detail

AbstractView

public AbstractView()
Method Detail

setBeanName

public void setBeanName(java.lang.String beanName)
Set the view's name. Helpful for traceability.

Framework code must call this when constructing views.

Specified by:
setBeanName in interface BeanNameAware
Parameters:
beanName - the name of the bean in the factory. Note that this name is the actual bean name used in the factory, which may differ from the originally specified name: in particular for inner bean names, the actual bean name might have been made unique through appending "#..." suffixes. Use the BeanFactoryUtils.originalBeanName(String) method to extract the original bean name (without suffix), if desired.

getBeanName

public java.lang.String getBeanName()
Return the view's name. Should never be null, if the view was correctly configured.


setContentType

public void setContentType(java.lang.String contentType)
Set the content type for this view. Default is "text/html;charset=ISO-8859-1".

May be ignored by subclasses if the view itself is assumed to set the content type, e.g. in case of JSPs.


getContentType

public java.lang.String getContentType()
Return the content type for this view.

Specified by:
getContentType in interface View
Returns:
the content type String (optionally including a character set), or null if not predetermined.

setRequestContextAttribute

public void setRequestContextAttribute(java.lang.String requestContextAttribute)
Set the name of the RequestContext attribute for this view. Default is none.


getRequestContextAttribute

public java.lang.String getRequestContextAttribute()
Return the name of the RequestContext attribute, if any.


setAttributesCSV

public void setAttributesCSV(java.lang.String propString)
                      throws java.lang.IllegalArgumentException
Set static attributes as a CSV string. Format is: attname0={value1},attname1={value1}

"Static" attributes are fixed attributes that are specified in the View instance configuration. "Dynamic" attributes, on the other hand, are values passed in as part of the model.

Throws:
java.lang.IllegalArgumentException

setAttributes

public void setAttributes(java.util.Properties attributes)
Set static attributes for this view from a java.util.Properties object.

"Static" attributes are fixed attributes that are specified in the View instance configuration. "Dynamic" attributes, on the other hand, are values passed in as part of the model.

This is the most convenient way to set static attributes. Note that static attributes can be overridden by dynamic attributes, if a value with the same name is included in the model.

Can be populated with a String "value" (parsed via PropertiesEditor) or a "props" element in XML bean definitions.

See Also:
PropertiesEditor

setAttributesMap

public void setAttributesMap(java.util.Map<java.lang.String,?> attributes)
Set static attributes for this view from a Map. This allows to set any kind of attribute values, for example bean references.

"Static" attributes are fixed attributes that are specified in the View instance configuration. "Dynamic" attributes, on the other hand, are values passed in as part of the model.

Can be populated with a "map" or "props" element in XML bean definitions.

Parameters:
attributes - Map with name Strings as keys and attribute objects as values

getAttributesMap

public java.util.Map<java.lang.String,java.lang.Object> getAttributesMap()
Allow Map access to the static attributes of this view, with the option to add or override specific entries.

Useful for specifying entries directly, for example via "attributesMap[myKey]". This is particularly useful for adding or overriding entries in child view definitions.


addStaticAttribute

public void addStaticAttribute(java.lang.String name,
                               java.lang.Object value)
Add static data to this view, exposed in each view.

"Static" attributes are fixed attributes that are specified in the View instance configuration. "Dynamic" attributes, on the other hand, are values passed in as part of the model.

Must be invoked before any calls to render.

Parameters:
name - the name of the attribute to expose
value - the attribute value to expose
See Also:
render(java.util.Map, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

getStaticAttributes

public java.util.Map<java.lang.String,java.lang.Object> getStaticAttributes()
Return the static attributes for this view. Handy for testing.

Returns an unmodifiable Map, as this is not intended for manipulating the Map but rather just for checking the contents.

Returns:
the static attributes in this view

setExposePathVariables

public void setExposePathVariables(boolean exposePathVariables)
Whether to add path variables in the model or not.

Path variables are commonly bound to URI template variables through the @PathVariable annotation. They're are effectively URI template variables with type conversion applied to them to derive typed Object values. Such values are frequently needed in views for constructing links to the same and other URLs.

Path variables added to the model override static attributes (see setAttributes(Properties)) but not attributes already present in the model.

By default this flag is set to true. Concrete view types can override this.

Parameters:
exposePathVariables - true to expose path variables, and false otherwise.

isExposePathVariables

public boolean isExposePathVariables()
Returns the value of the flag indicating whether path variables should be added to the model or not.


render

public void render(java.util.Map<java.lang.String,?> model,
                   javax.servlet.http.HttpServletRequest request,
                   javax.servlet.http.HttpServletResponse response)
            throws java.lang.Exception
Prepares the view given the specified model, merging it with static attributes and a RequestContext attribute, if necessary. Delegates to renderMergedOutputModel for the actual rendering.

Specified by:
render in interface View
Parameters:
model - Map with name Strings as keys and corresponding model objects as values (Map can also be null in case of empty model)
request - current HTTP request
response - HTTP response we are building
Throws:
java.lang.Exception - if rendering failed
See Also:
renderMergedOutputModel(java.util.Map, javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse)

createMergedOutputModel

protected java.util.Map<java.lang.String,java.lang.Object> createMergedOutputModel(java.util.Map<java.lang.String,?> model,
                                                                                   javax.servlet.http.HttpServletRequest request,
                                                                                   javax.servlet.http.HttpServletResponse response)
Creates a combined output Map (never null) that includes dynamic values and static attributes. Dynamic values take precedence over static attributes.


createRequestContext

protected RequestContext createRequestContext(javax.servlet.http.HttpServletRequest request,
                                              javax.servlet.http.HttpServletResponse response,
                                              java.util.Map<java.lang.String,java.lang.Object> model)
Create a RequestContext to expose under the specified attribute name.

Default implementation creates a standard RequestContext instance for the given request and model. Can be overridden in subclasses for custom instances.

Parameters:
request - current HTTP request
model - combined output Map (never null), with dynamic values taking precedence over static attributes
Returns:
the RequestContext instance
See Also:
setRequestContextAttribute(java.lang.String), RequestContext

prepareResponse

protected void prepareResponse(javax.servlet.http.HttpServletRequest request,
                               javax.servlet.http.HttpServletResponse response)
Prepare the given response for rendering.

The default implementation applies a workaround for an IE bug when sending download content via HTTPS.

Parameters:
request - current HTTP request
response - current HTTP response

generatesDownloadContent

protected boolean generatesDownloadContent()
Return whether this view generates download content (typically binary content like PDF or Excel files).

The default implementation returns false. Subclasses are encouraged to return true here if they know that they are generating download content that requires temporary caching on the client side, typically via the response OutputStream.

See Also:
prepareResponse(javax.servlet.http.HttpServletRequest, javax.servlet.http.HttpServletResponse), ServletResponse.getOutputStream()

renderMergedOutputModel

protected abstract void renderMergedOutputModel(java.util.Map<java.lang.String,java.lang.Object> model,
                                                javax.servlet.http.HttpServletRequest request,
                                                javax.servlet.http.HttpServletResponse response)
                                         throws java.lang.Exception
Subclasses must implement this method to actually render the view.

The first step will be preparing the request: In the JSP case, this would mean setting model objects as request attributes. The second step will be the actual rendering of the view, for example including the JSP via a RequestDispatcher.

Parameters:
model - combined output Map (never null), with dynamic values taking precedence over static attributes
request - current HTTP request
response - current HTTP response
Throws:
java.lang.Exception - if rendering failed

exposeModelAsRequestAttributes

protected void exposeModelAsRequestAttributes(java.util.Map<java.lang.String,java.lang.Object> model,
                                              javax.servlet.http.HttpServletRequest request)
                                       throws java.lang.Exception
Expose the model objects in the given map as request attributes. Names will be taken from the model Map. This method is suitable for all resources reachable by RequestDispatcher.

Parameters:
model - Map of model objects to expose
request - current HTTP request
Throws:
java.lang.Exception

createTemporaryOutputStream

protected java.io.ByteArrayOutputStream createTemporaryOutputStream()
Create a temporary OutputStream for this view.

This is typically used as IE workaround, for setting the content length header from the temporary stream before actually writing the content to the HTTP response.


writeToResponse

protected void writeToResponse(javax.servlet.http.HttpServletResponse response,
                               java.io.ByteArrayOutputStream baos)
                        throws java.io.IOException
Write the given temporary OutputStream to the HTTP response.

Parameters:
response - current HTTP response
baos - the temporary OutputStream to write
Throws:
java.io.IOException - if writing/flushing failed

toString

public java.lang.String toString()
Overrides:
toString in class java.lang.Object

Spring Framework