org.ibisph.filter.artifact
Class Filter

java.lang.Object
  org.ibisph.filter.AbstractPathPatternFilter
      org.ibisph.filter.artifact.Filter

All Implemented Interfaces:

javax.servlet.Filter

public class Filter
extends AbstractPathPatternFilter

Controls creation and distribution of requested pages which are artifacted/ cached to a disk files. If the request does not match a specified URI pattern then normal downstream filter/servlet request/response processing is performed. Else if the URI's path does match the path patterns then the artifact directory is checked for the requested resource. If found it simply streams back the file and short circuits the rest of the downstream filter/servlet request/response processing. If it matches and the resource is not found then the current response is replaced with a wrapped response and normal processing continues. When the normal processing of the request/response has been completed, the wrapped response's contents are then saved to the artifact directory and streamed back to the user.

NOTE: Two path adjustments are needed for artifacting: 1) compressed content and 2) pages that contain SVG charts or maps. The prior is needed because a request may or may not come from a browser that does not accept compressed (gzipped) responses. The latter is similar as some users might not have the SVG plugin or want their charts/maps delivered as a JPEG image. In either case these artifacts need to be stored in different directories so that the correct content is returned. The graphic type request parameter is used to control the way the SVG/JPEG pages are generated. This value is specified in two ways: 1) as a cookie which means the user specified that they always want SVG or JPEG. 2) on the URL which overrides the default graphic type - e.g. explicitly set by the user when making the request.

Listed below are the filter init params that specify how this filter is controlled.

PARAMETER NAME	INIT-PARAM DESCRIPTION
_URIPatternFilter	Standard _URIPatternFilter "init-param"s
Artifact.RequestPathType	Optional type of artifact path to use to save/retrieve files from. This controls if the filter uses the request's URI or the request's path info for where to get/put the artifacted files from/to. Valid values are "URI" or "PathInfo". If nothing is specified then the "URI" is used. URI allows for handling deployments that have mulitple context entry points defined with separate caches. This is needed so that other local page resource link addressing works properly.
Artifact.BasePath	Optional path of where to save/get the artifacted files to/from. If nothing is specified, the default is the root path of either the application's context if the Base.PathType is set to "C"ontext, or the application server's working directory if it is anything else. See the "Base.PathType" description for optional control of the path type.
Artifact.BasePathType	Optional type of base path specified. This controls if the path is based on the servlet context path (value of "C"), or an absolute file path (as would be needed for a clustered environment - shared file server). Value values are: "C", "F". If not specified the default is "C". If something other than "C" is used then it counts as "F".
CompressedAtrifact.BasePathSuffix	Required if the compression filter is implemented. This value is appended to the base path and specifies where to save/get compressed artifacted files to/from. If no value specified then the filter will NOT check for the user's browser supporting compression. If the compression is then used then the resultant artifact may or may not be compressed and will be returned to the user as it exists. See the optional Compressed.FileExtension.List for a further refinement of files that should be compressed.
ArtifactGraphicTypePage.BasePathSuffix	Required if the system implements SVG and any other type of graphic chart/map. This value is appended to the base path (after the compressed path) and specifies where to save/get SVG artifacted page files to/from. If no value specified then the filter will NOT check for the user's browser supporting SVG. This has huge issues if the system produces both JPEG and SVG pages. The resultant artifact will either be SVG or JPEG and will be returned to the user as it is first created. See the optional "SVG.List" for a further refinement of files that contain SVG or JPEG graphics.
GraphicType.RequestParameterName	Request parameter name (key) that is used by the system.
GraphicType.RequestParameterValue	Request parameter value that is specified by the system. If this value matches the request's value then the GraphicTypePage.Base.PathSuffix will be added to the base path.
CompressedFilePattern.MatchList	List of file extensions that are compressed (if client supports). This controls two things 1) If client supports and found in the compressed directory then the response is streamed back based on the disk file and the clients header is set to content gzip. 2) If content not found then wrap the response and when received back save to a disk file (according to if compressed or not). IMPORTANT NOTE: This is a configuration dependency with the compression filter. The extensions must match and the compression filter must be present for this to work properly.
CompressedFilePattern.MatchListSeperator	Optional list separator character used to delimit the Match List items.
CompressedFilePattern.RequestPathType	Controls the type of path to check against URI or PathInfo.
CompressedFilePattern.MatchType	Controls the type of match to test - "c"ontains or "p"refix.
ArtifactFile.LifeDuration	Value which controls how long a file can exist before it should be refreshed/rebuilt by the system. The value is seconds. The value is added to the file's last modified time. If the value+ last modified are greater than the current time the file is refreshed. Else it's within the cache window and it's contents are streamed back. If no value is specified or if any negative value is specified the value is the Java max long (e.g. 2^64 = very long time even in ms).
Path Patterns	Typical pattern path list properties.

Author:

Garth Braithwaite.

See Also:

Most of the code lifted from JSP Book (www.jspbook.com)., AbstractPathPatternFilter

Nested Class Summary

Nested classes/interfaces inherited from class org.ibisph.filter.AbstractPathPatternFilter

AbstractPathPatternFilter.PathPattern

Field Summary

protected java.lang.String	basePath
protected java.lang.String	compressedBasePathSuffix
protected AbstractPathPatternFilter.PathPattern	compressedPathPattern
protected java.lang.String	DEFAULT_BASE_PATH
protected java.lang.String	DEFAULT_COMPRESSED_BASE_PATH_SUFFIX
protected java.lang.String	DEFAULT_GRAPHIC_TYPE_BASE_PATH_SUFFIX
protected java.lang.String	DEFAULT_GRAPHIC_TYPE_PARAMETER_NAME
protected java.lang.String	DEFAULT_GRAPHIC_TYPE_PARAMETER_VALUE
protected java.lang.String	graphicTypePageBasePathSuffix
protected java.lang.String	graphicTypeParameterName
protected java.lang.String	graphicTypeParameterValue
protected boolean	isArtifactPathTypeURI
protected long	lifeOfFile
protected int	MIN_TEMP_FILE_SIZE_TO_QUALIFY_AS_GOOD_FILE
protected javax.servlet.ServletContext	servletContext
protected int	tempFilenameCounter

Fields inherited from class org.ibisph.filter.AbstractPathPatternFilter

LIST_SEPERATOR_PARAM_NAME, MATCH_LIST_PARAM_NAME, MATCH_TYPE_PARAM_NAME, pathPattern, REQUEST_PATH_TYPE_PARAM_NAME

Constructor Summary

Filter()

Method Summary

void	destroy() Required filter method.
void	doFilter(javax.servlet.ServletRequest req, javax.servlet.ServletResponse res, javax.servlet.FilterChain chain) Handles saving and returning requests cached to/from a disk file.
void	init(javax.servlet.FilterConfig filterConfig) Sets the filter's control properties via the init-parameters (located in the application's deployment web.xml file).

Methods inherited from class org.ibisph.filter.AbstractPathPatternFilter

getInitParameterValue

Methods inherited from class java.lang.Object

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

Field Detail

MIN_TEMP_FILE_SIZE_TO_QUALIFY_AS_GOOD_FILE

protected int MIN_TEMP_FILE_SIZE_TO_QUALIFY_AS_GOOD_FILE

DEFAULT_BASE_PATH

protected java.lang.String DEFAULT_BASE_PATH

DEFAULT_COMPRESSED_BASE_PATH_SUFFIX

protected java.lang.String DEFAULT_COMPRESSED_BASE_PATH_SUFFIX

DEFAULT_GRAPHIC_TYPE_BASE_PATH_SUFFIX

protected java.lang.String DEFAULT_GRAPHIC_TYPE_BASE_PATH_SUFFIX

DEFAULT_GRAPHIC_TYPE_PARAMETER_NAME

protected java.lang.String DEFAULT_GRAPHIC_TYPE_PARAMETER_NAME

DEFAULT_GRAPHIC_TYPE_PARAMETER_VALUE

protected java.lang.String DEFAULT_GRAPHIC_TYPE_PARAMETER_VALUE

servletContext

protected javax.servlet.ServletContext servletContext

lifeOfFile

protected long lifeOfFile

tempFilenameCounter

protected int tempFilenameCounter

isArtifactPathTypeURI

protected boolean isArtifactPathTypeURI

basePath

protected java.lang.String basePath

compressedBasePathSuffix

protected java.lang.String compressedBasePathSuffix

graphicTypePageBasePathSuffix

protected java.lang.String graphicTypePageBasePathSuffix

graphicTypeParameterName

protected java.lang.String graphicTypeParameterName

graphicTypeParameterValue

protected java.lang.String graphicTypeParameterValue

compressedPathPattern

protected AbstractPathPatternFilter.PathPattern compressedPathPattern

Constructor Detail

Filter

public Filter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)

Sets the filter's control properties via the init-parameters (located in the application's deployment web.xml file).

Specified by:

init in interface javax.servlet.Filter

Overrides:

init in class AbstractPathPatternFilter

Parameters:

filterConfig - Standard FilterConfig object passed to this filter from the container after object creation. The main info contained with the init parameters are the filtering patterns on which this filter acts on, and the base paths needed to save and retrieve the artifacted files, and the life duration of the artifact file before it becomes stale.

doFilter

public void doFilter(javax.servlet.ServletRequest req,
                     javax.servlet.ServletResponse res,
                     javax.servlet.FilterChain chain)
              throws java.io.IOException,
                     javax.servlet.ServletException

Handles saving and returning requests cached to/from a disk file. If the request is a candidate for artifacting e.g. matches the path patterns specified, then build the artifact path according to compression support and GraphicType. Next, concat the path with the resource's path (URI or pathinfo). Then check to see if an atrifacted file (same requested resource) exists. If it has, then check the file's creation date and time and check against the life value. If within the value then simply stream back. If not then wrap the response so that the returned response stream can be captured and saved to a file for future request responses.

Basic Logic: Check path patterns and query string. If no match or query string then do normal. If the compressable path is set AND if request supports gzip AND if the extension is in the list then adjust the base path. Next if the request contains a graphic type parameter and the value matches then append the graphic type path suffix to the base path. Finally, if using the URI artifacting path then get the request's URI else get the request's Path Info. Append that path to the base path for the artifact filename. If file exists, check for the file to be exipred. If expired or not found then wrap the response and do normal processing. When normal processing is finished save the wrapped response's content to the artifact filename. If found and not expired then simply stream the artifact file's contents back to the requestor.

Parameters:

req - Original request.

res - Original response.

chain - Filter chain to call for normal filter/servlet request/ response handling.

Throws:

java.io.IOException

javax.servlet.ServletException

destroy

public void destroy()

Required filter method. Clears the Servlet Context and Filter Config objects.

Specified by:

destroy in interface javax.servlet.Filter

Overrides:

destroy in class AbstractPathPatternFilter