public abstract class ResourceHelper extends Object
Implementations of this class contain the knowledge for finding and serving web application resources.
Constructor and Description |
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ResourceHelper() |
Modifier and Type | Method and Description |
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protected boolean |
clientAcceptsCompression(FacesContext ctx)
This method attempt to verify that the user agent can accept a gzip
encoded response by interrogating the
Accept-Encoding
requester header. |
protected boolean |
compressContent(ClientResourceInfo info)
Utility method to compress the content of the original resource
to the temporary directory specified by
ClientResourceInfo.getCompressedPath() . |
abstract LibraryInfo |
findLibrary(String libraryName,
String localePrefix,
String contract,
FacesContext ctx)
Search for the specified library/localPrefix combination in an
implementation dependent manner.
|
abstract ResourceInfo |
findResource(LibraryInfo library,
String resourceName,
String localePrefix,
boolean compressable,
FacesContext ctx)
Search for the specified resource based in the library/localePrefix/resourceName
combination in an implementation dependent manner.
|
abstract String |
getBaseContractsPath() |
protected String |
getBasePath(String contract) |
abstract String |
getBaseResourcePath() |
InputStream |
getInputStream(ResourceInfo toStream,
FacesContext ctx)
If the resource is compressable, return an InputStream to read the
compressed content, otherwise, call
getNonCompressedInputStream(ResourceInfo, javax.faces.context.FacesContext)
to return the content of the original resource. |
long |
getLastModified(ResourceInfo resource,
FacesContext ctx)
The default implementation of this method will call through to
getURL(ResourceInfo, javax.faces.context.FacesContext)
and leverage the URL to obtain the date information of the resource and
return the value of URLConnection.getLastModified() |
protected abstract InputStream |
getNonCompressedInputStream(ResourceInfo info,
FacesContext ctx)
If a
ResourceInfo is not compressable, getInputStream(ResourceInfo, javax.faces.context.FacesContext)
will call this method to return a stream to the actual resource. |
abstract URL |
getURL(ResourceInfo resource,
FacesContext ctx) |
protected VersionInfo |
getVersion(Collection<String> resourcePaths,
boolean isResource)
Given a collection of path names:
|
protected ClientResourceInfo |
handleCompression(ClientResourceInfo resource)
Utility method to peform the necessary actions to compress content.
|
protected boolean |
resourceSupportsEL(String resourceName,
String libraryName,
FacesContext ctx) |
protected String |
trimLeadingSlash(String s) |
public abstract String getBaseResourcePath()
public abstract String getBaseContractsPath()
public InputStream getInputStream(ResourceInfo toStream, FacesContext ctx) throws IOException
If the resource is compressable, return an InputStream to read the
compressed content, otherwise, call getNonCompressedInputStream(ResourceInfo, javax.faces.context.FacesContext)
to return the content of the original resource.
Implementation Note: If any exception occurs trying to return a stream to the compressed content, log the exception, and instead try to return a stream to the original content.
toStream
- the resource to obtain an InputStream toctx
- the FacesContext
for the current requestInputStream
to the resource, or
null
if no resource is foundIOException
- if an error occurs obtaining the streampublic abstract URL getURL(ResourceInfo resource, FacesContext ctx)
resource
- the resource to obtain a URL reference toctx
- the FacesContext
for the current requestnull
if no resource is foundpublic abstract LibraryInfo findLibrary(String libraryName, String localePrefix, String contract, FacesContext ctx)
libraryName
- the name of the librarylocalePrefix
- the logicial identifier for a locale specific library.
if no localePrefix is configured, pass null
contract
- the name of the contractctx
- the FacesContext
for the current request @return a LibraryInfo
if a matching library based off the inputs
can be found, otherwise returns null
public abstract ResourceInfo findResource(LibraryInfo library, String resourceName, String localePrefix, boolean compressable, FacesContext ctx)
Search for the specified resource based in the library/localePrefix/resourceName combination in an implementation dependent manner.
If the resource is found, and is compressable, call handleCompression(com.sun.faces.application.resource.ClientResourceInfo)
to compress the content.
library
- the library this resource should be a part of. If the
the resource that is being searched for isn't part of a library, then
pass null
resourceName
- the name of the resource that is being searched forlocalePrefix
- the logicial identifier for a locale specific library.
if no localePrefix is configured, pass null
compressable
- true
if the resource can be compressedctx
- the FacesContext
for the current requestResourceInfo
if a matching resource based off the inputs
can be found, otherwise returns null
public long getLastModified(ResourceInfo resource, FacesContext ctx)
The default implementation of this method will call through to
getURL(ResourceInfo, javax.faces.context.FacesContext)
and leverage the URL to obtain the date information of the resource and
return the value of URLConnection.getLastModified()
resource
- the resource in questionctx
- the FacesContext
for the current request0
if the date cannot be determinedprotected abstract InputStream getNonCompressedInputStream(ResourceInfo info, FacesContext ctx) throws IOException
ResourceInfo
is not compressable, getInputStream(ResourceInfo, javax.faces.context.FacesContext)
will call this method to return a stream to the actual resource.info
- the resource to obtain an InputStream toctx
- the FacesContext
for the current requestIOException
- if an error occurs obtaining the streamprotected VersionInfo getVersion(Collection<String> resourcePaths, boolean isResource)
Given a collection of path names:
1.1, scripts, images, 1.2
this method will pick out the directories that represent a library or resource version and return the latest version found, if any.
resourcePaths
- a collection of paths (consisting of single path
elements)isResource
- true
if the version being looked up
is for a reource, otherwise, pass false
if the version
is a library versionnull
protected boolean compressContent(ClientResourceInfo info) throws IOException
ClientResourceInfo.getCompressedPath()
.info
- the resource to be compressedtrue
if compression succeeded and the compressed
result is smaller than the original content, otherwise false
IOException
- if any error occur reading/writingprotected boolean clientAcceptsCompression(FacesContext ctx)
This method attempt to verify that the user agent can accept a gzip
encoded response by interrogating the Accept-Encoding
requester header. If it is determined safe to send a gzip encoded
response, send the Content-Encoding
header with a value
of gzip
.
See Parameters:
ctx
- the FacesContext
for the current requesttrue
if compressed content can be sent to the client,
otherwise false
protected ClientResourceInfo handleCompression(ClientResourceInfo resource)
Utility method to peform the necessary actions to compress content.
Implmentation Note: If an exception occurs while compressing the content,
log the IOException and rebuilt the ResourceInfo
as non-compressable.
resource
- the resource to compressionprotected boolean resourceSupportsEL(String resourceName, String libraryName, FacesContext ctx)
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