WebContentGenerator

java.lang.Object
- org.springframework.context.support.ApplicationObjectSupport
- - org.springframework.web.context.support.WebApplicationObjectSupport
  - - org.springframework.web.servlet.support.WebContentGenerator

All Implemented Interfaces:

Aware, ApplicationContextAware, ServletContextAware

Direct Known Subclasses:

AbstractController, AbstractHandlerMethodAdapter, ResourceHttpRequestHandler, WebContentInterceptor
```
public abstract class WebContentGenerator
extends WebApplicationObjectSupport
```
Convenient superclass for any kind of web content generator, like AbstractController and WebContentInterceptor. Can also be used for custom handlers that have their own HandlerAdapter.
Supports HTTP cache control options. The usage of corresponding HTTP headers can be controlled via the "cacheSeconds" and "cacheControl" properties.
NOTE: As of Spring 4.2, this generator's default behavior changed when using only setCacheSeconds(int), sending HTTP response headers that are in line with current browsers and proxies implementations (i.e. no HTTP 1.0 headers anymore) Reverting to the previous behavior can be easily done by using one of the newly deprecated methods setUseExpiresHeader(boolean), setUseCacheControlHeader(boolean), setUseCacheControlNoStore(boolean) or setAlwaysMustRevalidate(boolean).

Author:

Rod Johnson, Juergen Hoeller, Brian Clozel, Rossen Stoyanchev

See Also:

setCacheSeconds(int), setCacheControl(org.springframework.http.CacheControl), setRequireSession(boolean)

Field Summary

Fields
Modifier and Type	Field and Description
`private java.lang.String`	`allowHeader`
`private boolean`	`alwaysMustRevalidate`
`private CacheControl`	`cacheControl`
`private int`	`cacheSeconds`
`protected static java.lang.String`	`HEADER_CACHE_CONTROL`
`private static java.lang.String`	`HEADER_EXPIRES`
`private static java.lang.String`	`HEADER_PRAGMA`
`static java.lang.String`	`METHOD_GET` HTTP method "GET"
`static java.lang.String`	`METHOD_HEAD` HTTP method "HEAD"
`static java.lang.String`	`METHOD_POST` HTTP method "POST"
`private boolean`	`requireSession`
`private java.util.Set<java.lang.String>`	`supportedMethods` Set of supported HTTP methods
`private boolean`	`useCacheControlHeader` Use HTTP 1.1 cache-control header?
`private boolean`	`useCacheControlNoStore` Use HTTP 1.1 cache-control header value "no-store"?
`private boolean`	`useExpiresHeader` Use HTTP 1.0 expires header?
`private java.lang.String[]`	`varyByRequestHeaders`

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

Constructor Summary

Constructors
Constructor and Description
`WebContentGenerator()` Create a new WebContentGenerator which supports HTTP methods GET, HEAD and POST by default.
`WebContentGenerator(boolean restrictDefaultSupportedMethods)` Create a new WebContentGenerator.
`WebContentGenerator(java.lang.String... supportedMethods)` Create a new WebContentGenerator.

Method Summary

All Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected void`	`applyCacheControl(HttpServletResponse response, CacheControl cacheControl)` Set the HTTP Cache-Control header according to the given settings.
`protected void`	`applyCacheSeconds(HttpServletResponse response, int cacheSeconds)` Apply the given cache seconds and generate corresponding HTTP headers, i.e.
`protected void`	`applyCacheSeconds(HttpServletResponse response, int cacheSeconds, boolean mustRevalidate)` Deprecated. as of 4.2, in favor of `applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)`
`protected void`	`cacheForSeconds(HttpServletResponse response, int seconds)` Deprecated. as of 4.2, in favor of `applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)`
`protected void`	`cacheForSeconds(HttpServletResponse response, int seconds, boolean mustRevalidate)` Deprecated. as of 4.2, in favor of `applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)`
`protected void`	`checkAndPrepare(HttpServletRequest request, HttpServletResponse response, boolean lastModified)` Deprecated. as of 4.2, since the `lastModified` flag is effectively ignored, with a must-revalidate header only generated if explicitly configured
`protected void`	`checkAndPrepare(HttpServletRequest request, HttpServletResponse response, int cacheSeconds, boolean lastModified)` Deprecated. as of 4.2, since the `lastModified` flag is effectively ignored, with a must-revalidate header only generated if explicitly configured
`protected void`	`checkRequest(HttpServletRequest request)` Check the given request for supported methods and a required session, if any.
`protected java.lang.String`	`getAllowHeader()` Return the "Allow" header value to use in response to an HTTP OPTIONS request based on the configured `supported methods` also automatically adding "OPTIONS" to the list even if not present as a supported method.
`CacheControl`	`getCacheControl()` Get the `CacheControl` instance that builds the Cache-Control HTTP response header.
`int`	`getCacheSeconds()` Return the number of seconds that content is cached.
`java.lang.String[]`	`getSupportedMethods()` Return the HTTP methods that this content generator supports.
`java.lang.String[]`	`getVaryByRequestHeaders()` Return the configured request header names for the "Vary" response header.
`private java.util.Collection<java.lang.String>`	`getVaryRequestHeadersToAdd(HttpServletResponse response)`
`private void`	`initAllowHeader()`
`boolean`	`isAlwaysMustRevalidate()` Deprecated. as of 4.2, in favor of `getCacheControl()`
`boolean`	`isRequireSession()` Return whether a session is required to handle requests.
`boolean`	`isUseCacheControlHeader()` Deprecated. as of 4.2, in favor of `getCacheControl()`
`boolean`	`isUseCacheControlNoStore()` Deprecated. as of 4.2, in favor of `getCacheControl()`
`boolean`	`isUseExpiresHeader()` Deprecated. as of 4.2, in favor of `getCacheControl()`
`protected void`	`prepareResponse(HttpServletResponse response)` Prepare the given response according to the settings of this generator.
`protected void`	`preventCaching(HttpServletResponse response)` Deprecated. as of 4.2, in favor of `applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)`
`void`	`setAlwaysMustRevalidate(boolean mustRevalidate)` Deprecated. as of 4.2, in favor of `setCacheControl(org.springframework.http.CacheControl)`
`void`	`setCacheControl(CacheControl cacheControl)` Set the `CacheControl` instance to build the Cache-Control HTTP response header.
`void`	`setCacheSeconds(int seconds)` Cache content for the given number of seconds, by writing cache-related HTTP headers to the response: seconds == -1 (default value): no generation cache-related headers seconds == 0: "Cache-Control: no-store" will prevent caching seconds > 0: "Cache-Control: max-age=seconds" will ask to cache content
`void`	`setRequireSession(boolean requireSession)` Set whether a session should be required to handle requests.
`void`	`setSupportedMethods(java.lang.String... methods)` Set the HTTP methods that this content generator should support.
`void`	`setUseCacheControlHeader(boolean useCacheControlHeader)` Deprecated. as of 4.2, since going forward, the HTTP 1.1 cache-control header will be required, with the HTTP 1.0 headers disappearing
`void`	`setUseCacheControlNoStore(boolean useCacheControlNoStore)` Deprecated. as of 4.2, in favor of `setCacheControl(org.springframework.http.CacheControl)`
`void`	`setUseExpiresHeader(boolean useExpiresHeader)` Deprecated. as of 4.2, since going forward, the HTTP 1.1 cache-control header will be required, with the HTTP 1.0 headers disappearing
`void`	`setVaryByRequestHeaders(java.lang.String... varyByRequestHeaders)` Configure one or more request header names (e.g.

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, toString, wait, wait, wait

- Field Detail
  - METHOD_GET
```
public static final java.lang.String METHOD_GET
```
    HTTP method "GET"
    
    See Also:
    
    Constant Field Values
  - METHOD_HEAD
```
public static final java.lang.String METHOD_HEAD
```
    HTTP method "HEAD"
    
    See Also:
    
    Constant Field Values
  - METHOD_POST
```
public static final java.lang.String METHOD_POST
```
    HTTP method "POST"
    
    See Also:
    
    Constant Field Values
  - HEADER_PRAGMA
```
private static final java.lang.String HEADER_PRAGMA
```
    See Also:
    
    Constant Field Values
  - HEADER_EXPIRES
```
private static final java.lang.String HEADER_EXPIRES
```
    See Also:
    
    Constant Field Values
  - HEADER_CACHE_CONTROL
```
protected static final java.lang.String HEADER_CACHE_CONTROL
```
    See Also:
    
    Constant Field Values
  - supportedMethods
```
private java.util.Set<java.lang.String> supportedMethods
```
    Set of supported HTTP methods
  - allowHeader
```
private java.lang.String allowHeader
```
  - requireSession
```
private boolean requireSession
```
  - cacheControl
```
private CacheControl cacheControl
```
  - cacheSeconds
```
private int cacheSeconds
```
  - varyByRequestHeaders
```
private java.lang.String[] varyByRequestHeaders
```
  - useExpiresHeader
```
private boolean useExpiresHeader
```
    Use HTTP 1.0 expires header?
  - useCacheControlHeader
```
private boolean useCacheControlHeader
```
    Use HTTP 1.1 cache-control header?
  - useCacheControlNoStore
```
private boolean useCacheControlNoStore
```
    Use HTTP 1.1 cache-control header value "no-store"?
  - alwaysMustRevalidate
```
private boolean alwaysMustRevalidate
```
- Constructor Detail
  - WebContentGenerator
```
public WebContentGenerator()
```
    Create a new WebContentGenerator which supports HTTP methods GET, HEAD and POST by default.
  - WebContentGenerator
```
public WebContentGenerator(boolean restrictDefaultSupportedMethods)
```
    Create a new WebContentGenerator.
    
    Parameters:
    
    restrictDefaultSupportedMethods - true if this generator should support HTTP methods GET, HEAD and POST by default, or false if it should be unrestricted
  - WebContentGenerator
```
public WebContentGenerator(java.lang.String... supportedMethods)
```
    Create a new WebContentGenerator.
    
    Parameters:
    
    supportedMethods - the supported HTTP methods for this content generator
- Method Detail
  - setSupportedMethods
```
public final void setSupportedMethods(java.lang.String... methods)
```
    Set the HTTP methods that this content generator should support.
    Default is GET, HEAD and POST for simple form controller types; unrestricted for general controllers and interceptors.
  - getSupportedMethods
```
public final java.lang.String[] getSupportedMethods()
```
    Return the HTTP methods that this content generator supports.
  - initAllowHeader
```
private void initAllowHeader()
```
  - getAllowHeader
```
protected java.lang.String getAllowHeader()
```
    Return the "Allow" header value to use in response to an HTTP OPTIONS request based on the configured supported methods also automatically adding "OPTIONS" to the list even if not present as a supported method. This means sub-classes don't have to explicitly list "OPTIONS" as a supported method as long as HTTP OPTIONS requests are handled before making a call to checkRequest(HttpServletRequest).
  - setRequireSession
```
public final void setRequireSession(boolean requireSession)
```
    Set whether a session should be required to handle requests.
  - isRequireSession
```
public final boolean isRequireSession()
```
    Return whether a session is required to handle requests.
  - setCacheControl
```
public final void setCacheControl(CacheControl cacheControl)
```
    Set the CacheControl instance to build the Cache-Control HTTP response header.
    
    Since:
    
    4.2
  - getCacheControl
```
public final CacheControl getCacheControl()
```
    Get the CacheControl instance that builds the Cache-Control HTTP response header.
    
    Since:
    
    4.2
  - setCacheSeconds
```
public final void setCacheSeconds(int seconds)
```
    Cache content for the given number of seconds, by writing cache-related HTTP headers to the response:
    - seconds == -1 (default value): no generation cache-related headers
    - seconds == 0: "Cache-Control: no-store" will prevent caching
    - seconds > 0: "Cache-Control: max-age=seconds" will ask to cache content
    For more specific needs, a custom CacheControl should be used.
    See Also:
    
    setCacheControl(org.springframework.http.CacheControl)
  - getCacheSeconds
```
public final int getCacheSeconds()
```
    Return the number of seconds that content is cached.
  - setVaryByRequestHeaders
```
public final void setVaryByRequestHeaders(java.lang.String... varyByRequestHeaders)
```
    Configure one or more request header names (e.g. "Accept-Language") to add to the "Vary" response header to inform clients that the response is subject to content negotiation and variances based on the value of the given request headers. The configured request header names are added only if not already present in the response "Vary" header.
    
    Parameters:
    
    varyByRequestHeaders - one or more request header names
    
    Since:
    
    4.3
  - getVaryByRequestHeaders
```
public final java.lang.String[] getVaryByRequestHeaders()
```
    Return the configured request header names for the "Vary" response header.
    
    Since:
    
    4.3
  - setUseExpiresHeader
```
@Deprecated
public final void setUseExpiresHeader(boolean useExpiresHeader)
```
    Deprecated. as of 4.2, since going forward, the HTTP 1.1 cache-control header will be required, with the HTTP 1.0 headers disappearing
    
    Set whether to use the HTTP 1.0 expires header. Default is "false", as of 4.2.
    Note: Cache headers will only get applied if caching is enabled (or explicitly prevented) for the current request.
  - isUseExpiresHeader
```
@Deprecated
public final boolean isUseExpiresHeader()
```
    Deprecated. as of 4.2, in favor of getCacheControl()
    
    Return whether the HTTP 1.0 expires header is used.
  - setUseCacheControlHeader
```
@Deprecated
public final void setUseCacheControlHeader(boolean useCacheControlHeader)
```
    Deprecated. as of 4.2, since going forward, the HTTP 1.1 cache-control header will be required, with the HTTP 1.0 headers disappearing
    
    Set whether to use the HTTP 1.1 cache-control header. Default is "true".
    Note: Cache headers will only get applied if caching is enabled (or explicitly prevented) for the current request.
  - isUseCacheControlHeader
```
@Deprecated
public final boolean isUseCacheControlHeader()
```
    Deprecated. as of 4.2, in favor of getCacheControl()
    
    Return whether the HTTP 1.1 cache-control header is used.
  - setUseCacheControlNoStore
```
@Deprecated
public final void setUseCacheControlNoStore(boolean useCacheControlNoStore)
```
    Deprecated. as of 4.2, in favor of setCacheControl(org.springframework.http.CacheControl)
    
    Set whether to use the HTTP 1.1 cache-control header value "no-store" when preventing caching. Default is "true".
  - isUseCacheControlNoStore
```
@Deprecated
public final boolean isUseCacheControlNoStore()
```
    Deprecated. as of 4.2, in favor of getCacheControl()
    
    Return whether the HTTP 1.1 cache-control header value "no-store" is used.
  - setAlwaysMustRevalidate
```
@Deprecated
public final void setAlwaysMustRevalidate(boolean mustRevalidate)
```
    Deprecated. as of 4.2, in favor of setCacheControl(org.springframework.http.CacheControl)
    
    An option to add 'must-revalidate' to every Cache-Control header. This may be useful with annotated controller methods, which can programmatically do a last-modified calculation as described in WebRequest.checkNotModified(long).
    Default is "false".
  - isAlwaysMustRevalidate
```
@Deprecated
public final boolean isAlwaysMustRevalidate()
```
    Deprecated. as of 4.2, in favor of getCacheControl()
    
    Return whether 'must-revalidate' is added to every Cache-Control header.
  - checkRequest
```
protected final void checkRequest(HttpServletRequest request)
                           throws ServletException
```
    Check the given request for supported methods and a required session, if any.
    
    Parameters:
    
    request - current HTTP request
    
    Throws:
    
    ServletException - if the request cannot be handled because a check failed
    
    Since:
    
    4.2
  - prepareResponse
```
protected final void prepareResponse(HttpServletResponse response)
```
    Prepare the given response according to the settings of this generator. Applies the number of cache seconds specified for this generator.
    
    Parameters:
    
    response - current HTTP response
    
    Since:
    
    4.2
  - applyCacheControl
```
protected final void applyCacheControl(HttpServletResponse response,
                                       CacheControl cacheControl)
```
    Set the HTTP Cache-Control header according to the given settings.
    
    Parameters:
    
    response - current HTTP response
    
    cacheControl - the pre-configured cache control settings
    
    Since:
    
    4.2
  - applyCacheSeconds
```
protected final void applyCacheSeconds(HttpServletResponse response,
                                       int cacheSeconds)
```
    Apply the given cache seconds and generate corresponding HTTP headers, i.e. allow caching for the given number of seconds in case of a positive value, prevent caching if given a 0 value, do nothing else. Does not tell the browser to revalidate the resource.
    
    Parameters:
    
    response - current HTTP response
    
    cacheSeconds - positive number of seconds into the future that the response should be cacheable for, 0 to prevent caching
  - checkAndPrepare
```
@Deprecated
protected final void checkAndPrepare(HttpServletRequest request,
                                                 HttpServletResponse response,
                                                 boolean lastModified)
                                          throws ServletException
```
    Deprecated. as of 4.2, since the lastModified flag is effectively ignored, with a must-revalidate header only generated if explicitly configured
    
    Throws:
    
    ServletException
    
    See Also:
    
    checkRequest(HttpServletRequest), prepareResponse(HttpServletResponse)
  - checkAndPrepare
```
@Deprecated
protected final void checkAndPrepare(HttpServletRequest request,
                                                 HttpServletResponse response,
                                                 int cacheSeconds,
                                                 boolean lastModified)
                                          throws ServletException
```
    Deprecated. as of 4.2, since the lastModified flag is effectively ignored, with a must-revalidate header only generated if explicitly configured
    
    Throws:
    
    ServletException
    
    See Also:
    
    checkRequest(HttpServletRequest), applyCacheSeconds(HttpServletResponse, int)
  - applyCacheSeconds
```
@Deprecated
protected final void applyCacheSeconds(HttpServletResponse response,
                                                   int cacheSeconds,
                                                   boolean mustRevalidate)
```
    Deprecated. as of 4.2, in favor of applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)
    
    Apply the given cache seconds and generate respective HTTP headers.
    That is, allow caching for the given number of seconds in the case of a positive value, prevent caching if given a 0 value, else do nothing (i.e. leave caching to the client).
    
    Parameters:
    
    response - the current HTTP response
    
    cacheSeconds - the (positive) number of seconds into the future that the response should be cacheable for; 0 to prevent caching; and a negative value to leave caching to the client.
    
    mustRevalidate - whether the client should revalidate the resource (typically only necessary for controllers with last-modified support)
  - cacheForSeconds
```
@Deprecated
protected final void cacheForSeconds(HttpServletResponse response,
                                                 int seconds)
```
    Deprecated. as of 4.2, in favor of applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)
    
    Set HTTP headers to allow caching for the given number of seconds. Does not tell the browser to revalidate the resource.
    
    Parameters:
    
    response - current HTTP response
    
    seconds - number of seconds into the future that the response should be cacheable for
  - cacheForSeconds
```
@Deprecated
protected final void cacheForSeconds(HttpServletResponse response,
                                                 int seconds,
                                                 boolean mustRevalidate)
```
    Deprecated. as of 4.2, in favor of applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)
    
    Set HTTP headers to allow caching for the given number of seconds. Tells the browser to revalidate the resource if mustRevalidate is true.
    
    Parameters:
    
    response - the current HTTP response
    
    seconds - number of seconds into the future that the response should be cacheable for
    
    mustRevalidate - whether the client should revalidate the resource (typically only necessary for controllers with last-modified support)
  - preventCaching
```
@Deprecated
protected final void preventCaching(HttpServletResponse response)
```
    Deprecated. as of 4.2, in favor of applyCacheControl(HttpServletResponse, org.springframework.http.CacheControl)
    
    Prevent the response from being cached. Only called in HTTP 1.0 compatibility mode.
    See http://www.mnot.net/cache_docs.
  - getVaryRequestHeadersToAdd
```
private java.util.Collection<java.lang.String> getVaryRequestHeadersToAdd(HttpServletResponse response)
```

Class WebContentGenerator

Field Summary

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

Constructor Summary

Method Summary

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

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

Methods inherited from class java.lang.Object

Field Detail

METHOD_GET

METHOD_HEAD

METHOD_POST

HEADER_PRAGMA

HEADER_EXPIRES

HEADER_CACHE_CONTROL

supportedMethods

allowHeader

requireSession

cacheControl

cacheSeconds

varyByRequestHeaders

useExpiresHeader

useCacheControlHeader

useCacheControlNoStore

alwaysMustRevalidate

Constructor Detail

WebContentGenerator

WebContentGenerator

WebContentGenerator

Method Detail

setSupportedMethods

getSupportedMethods

initAllowHeader

getAllowHeader

setRequireSession

isRequireSession

setCacheControl

getCacheControl

setCacheSeconds

getCacheSeconds

setVaryByRequestHeaders

getVaryByRequestHeaders

setUseExpiresHeader

isUseExpiresHeader

setUseCacheControlHeader

isUseCacheControlHeader

setUseCacheControlNoStore

isUseCacheControlNoStore

setAlwaysMustRevalidate

isAlwaysMustRevalidate

checkRequest

prepareResponse

applyCacheControl

applyCacheSeconds

checkAndPrepare

checkAndPrepare

applyCacheSeconds

cacheForSeconds

cacheForSeconds

preventCaching

getVaryRequestHeadersToAdd