org.springframework.extensions.surf

Class DependencyAggregator

java.lang.Object

org.springframework.extensions.surf.DependencyAggregator

All Implemented Interfaces:

org.springframework.beans.factory.Aware, org.springframework.context.ApplicationContextAware, CacheReporter

public class DependencyAggregator
extends Object
implements org.springframework.context.ApplicationContextAware, CacheReporter

Bean providing aggregating, compression and caching services for groups of Surf file resource dependencies.

Author:

David Draper, Kevin Roast

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	DependencyAggregator.CompressionType

Field Summary

Fields

Modifier and Type	Field and Description
int	cacheSize Set the size of the file cache for MD5 checksums
String	charset
static String	CLIENT_COLLATION_DEBUG
static String	CLIENT_DEBUG
boolean	disableOptimizations
static char	DOUBLE_QUOTE
static String	FLAGS
static String	INLINE_AGGREGATION_MARKER
int	linebreak
boolean	munge
static Pattern	p
boolean	preserveAllSemiColons
static char	SINGLE_QUOTE
boolean	verbose

Constructor Summary

Constructors

Constructor and Description
DependencyAggregator()

Method Summary

Methods

Modifier and Type	Method and Description
void	adjustImageURLs(String cssPath, StringBuilder cssContents) This method is used to ensure all image URL are correct when CSS files are aggregated together.
protected void	cacheChecksumForFileSet(Set<String> fileSet, String checksum) Caches a generated aggregated resource checksum against the fileset that it was generated against.
protected void	cacheCompressedCssResource(String path, String content) Caches the supplied CSS resource using a combination of the current Theme ID with the CSS source path.
protected void	cacheCompressedJSResource(String path, String content)
protected void	cacheDependencyResource(String checksum, DependencyResource content)
void	clearCaches()
String	compressCSSFile(InputStream in) Compresses the CSS file provided by the supplied InputStream using the YUI CssCompressor.
String	compressJavaScript(Reader reader) Compresses the JavaScript file provided by the supplied InputStream using the YUI JavaScriptCompressor.
boolean	excludeFileFromCompression(String path) Checks to see whether or not the path meets any of the compression exclusion criteria.
String	generateCSSDependencies(LinkedHashSet<String> paths) Generates a single compressed CSS resource from the supplied list of paths and returns an MD5 checksum value that should be passed to the browser to when requesting the dependencies from the server.
String	generateJavaScriptDependencies(LinkedHashSet<String> paths) Generates a single compressed JavaScript resource from the supplied list of paths and returns an MD5 checksum value that should be passed to the browser to when requesting the dependencies from the server.
String	getCachedChecksumForFileSet(Set<String> fileSet) This checks the cache to see if the requested set of files has previously been used to generate an aggregated resource.
String	getCachedCompressedCssResource(String path) Attempts to retrieve a previously cached CSS resource.
String	getCachedCompressedJSResource(String path)
DependencyResource	getCachedDependencyResource(String checksum) Attempts to retrieve a previously stored aggregated resource that has been mapped to a specific checksum.
DependencyHandler	getDependencyHandler()
protected Map<Set<String>,String>	getFileSetChecksumCache() Construct the File Set MD5 Checksum Cache Currently this cache is based on a ConcurrentLinkedHashMap impl - to maintain a maximum size and insert order allowing old items to be ejected in a deterministic pattern.
List<String>	getMissingFileWarningSuppressionList() Gets the paths to suppress missing file warnings for.
javax.servlet.ServletContext	getServletContext()
boolean	isCollationDebugMode() Indicates whether the client should operate in collation debug mode.
boolean	isDebugMode() Indicates whether the client should operate in debug mode.
protected String	processCssImport(String importContents, String cssPath, String importPath, Set<String> processedPaths) Processes a single CSS import request.
StringBuffer	processCssImports(String cssPath, String fileContents, Set<String> processedPaths) When aggregating CSS files together its important to process any import statements that are included.
List<CacheReport>	report()
void	setApplicationContext(org.springframework.context.ApplicationContext applicationContext)
void	setCacheSize(int cacheSize)
void	setCharset(String charset)
void	setCompressionExclusions(List<String> compressionExclusions)
void	setCssImageDataHandler(CssImageDataHandler cssImageDataHandler)
void	setCssThemeHandler(CssThemeHandler cssThemeHandler)
void	setDependencyHandler(DependencyHandler dependencyHandler)
void	setDisableOptimizations(boolean disableOptimizations)
void	setLinebreak(int linebreak)
void	setMissingFileWarningSuppressionList(List<String> missingFileWarningSuppressionList) Setter provided for Spring to set the missing file warning suppression list from the configuration.
void	setMunge(boolean munge)
void	setPreserveAllSemiColons(boolean preserveAllSemiColons)
void	setScriptConfigModel(org.springframework.extensions.webscripts.ScriptConfigModel scriptConfigModel)
void	setVerbose(boolean verbose)

Methods inherited from class java.lang.Object

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

Field Detail

charset

public String charset

linebreak

public int linebreak

munge

public boolean munge

verbose

public boolean verbose

preserveAllSemiColons

public boolean preserveAllSemiColons

disableOptimizations

public boolean disableOptimizations

FLAGS

public static final String FLAGS

See Also:

Constant Field Values

CLIENT_DEBUG

public static final String CLIENT_DEBUG

See Also:

Constant Field Values

CLIENT_COLLATION_DEBUG

public static final String CLIENT_COLLATION_DEBUG

See Also:

Constant Field Values

INLINE_AGGREGATION_MARKER

public static final String INLINE_AGGREGATION_MARKER

See Also:

Constant Field Values

cacheSize

public int cacheSize

Set the size of the file cache for MD5 checksums

SINGLE_QUOTE

public static char SINGLE_QUOTE

DOUBLE_QUOTE

public static char DOUBLE_QUOTE

p

public static final Pattern p

Constructor Detail

DependencyAggregator

public DependencyAggregator()

Method Detail

setCacheSize

public void setCacheSize(int cacheSize)

setCssImageDataHandler

public void setCssImageDataHandler(CssImageDataHandler cssImageDataHandler)

setCssThemeHandler

public void setCssThemeHandler(CssThemeHandler cssThemeHandler)

getDependencyHandler

public DependencyHandler getDependencyHandler()

setDependencyHandler

public void setDependencyHandler(DependencyHandler dependencyHandler)

setCompressionExclusions

public void setCompressionExclusions(List<String> compressionExclusions)

isDebugMode

public boolean isDebugMode()

Indicates whether the client should operate in debug mode. This means that all dependency resources should not be compressed or collated.

Returns:

boolean

isCollationDebugMode

public boolean isCollationDebugMode()

Indicates whether the client should operate in collation debug mode. This means that collated dependency resources should include the names of the files that have been collated.

Returns:

boolean

getServletContext

public javax.servlet.ServletContext getServletContext()

setApplicationContext

public void setApplicationContext(org.springframework.context.ApplicationContext applicationContext)
                           throws org.springframework.beans.BeansException

Specified by:

setApplicationContext in interface org.springframework.context.ApplicationContextAware

Throws:

org.springframework.beans.BeansException

setScriptConfigModel

public void setScriptConfigModel(org.springframework.extensions.webscripts.ScriptConfigModel scriptConfigModel)

getMissingFileWarningSuppressionList

public List<String> getMissingFileWarningSuppressionList()

Gets the paths to suppress missing file warnings for.

Returns:

A list of paths to suppress warnings for.

setMissingFileWarningSuppressionList

public void setMissingFileWarningSuppressionList(List<String> missingFileWarningSuppressionList)

Setter provided for Spring to set the missing file warning suppression list from the configuration.

Parameters:

missingFileWarningSuppressionList - The list of paths to suppress warnings for.

generateJavaScriptDependencies

public String generateJavaScriptDependencies(LinkedHashSet<String> paths)

Generates a single compressed JavaScript resource from the supplied list of paths and returns an MD5 checksum value that should be passed to the browser to when requesting the dependencies from the server. The combined compressed source is cached using the MD5 checksum as a key.

Parameters:

paths - A list of paths to compress and combine into a single resource.

Returns:

An MD5 checksum that can be used as a key to retrieve the resource from the cache.

generateCSSDependencies

public String generateCSSDependencies(LinkedHashSet<String> paths)

Generates a single compressed CSS resource from the supplied list of paths and returns an MD5 checksum value that should be passed to the browser to when requesting the dependencies from the server. The combined compressed source is cached using the MD5 checksum as a key.

Parameters:

paths - A list of paths to compress and combine into a single resource.

Returns:

An MD5 checksum that can be used as a key to retrieve the resource from the cache.

getCachedChecksumForFileSet

public String getCachedChecksumForFileSet(Set<String> fileSet)

This checks the cache to see if the requested set of files has previously been used to generate an aggregated resource. The supplied fileset is updated to include the current theme id to ensure that theme specific resources are returned (the theme id is removed after the cache is checked).

Parameters:

fileSet - Set

Returns:

String

cacheChecksumForFileSet

protected void cacheChecksumForFileSet(Set<String> fileSet,
                           String checksum)

Caches a generated aggregated resource checksum against the fileset that it was generated against. The current theme id is added to the fileset to ensure that resources are cached per theme.

Parameters:

fileSet - Set

checksum - String

getFileSetChecksumCache

protected Map<Set<String>,String> getFileSetChecksumCache()

Construct the File Set MD5 Checksum Cache Currently this cache is based on a ConcurrentLinkedHashMap impl - to maintain a maximum size and insert order allowing old items to be ejected in a deterministic pattern.

Returns:

cache Map

getCachedCompressedJSResource

public String getCachedCompressedJSResource(String path)

cacheCompressedJSResource

protected void cacheCompressedJSResource(String path,
                             String content)

getCachedCompressedCssResource

public String getCachedCompressedCssResource(String path)

Attempts to retrieve a previously cached CSS resource. Each CSS resource is cached using the current theme ID as a prefix. This is done so that the same CSS resource is not used when switching themes.

Parameters:

path - String

Returns:

String

cacheCompressedCssResource

protected void cacheCompressedCssResource(String path,
                              String content)

Caches the supplied CSS resource using a combination of the current Theme ID with the CSS source path.

Parameters:

path - String

content - String

getCachedDependencyResource

public DependencyResource getCachedDependencyResource(String checksum)

Attempts to retrieve a previously stored aggregated resource that has been mapped to a specific checksum.

Parameters:

checksum - The checksum to look in the cache for

Returns:

The previously cached DependencyResource or null if not cached.

cacheDependencyResource

protected void cacheDependencyResource(String checksum,
                           DependencyResource content)

clearCaches

public void clearCaches()

Specified by:

clearCaches in interface CacheReporter

report

public List<CacheReport> report()

Specified by:

report in interface CacheReporter

adjustImageURLs

public void adjustImageURLs(String cssPath,
                   StringBuilder cssContents)
                     throws IOException

This method is used to ensure all image URL are correct when CSS files are aggregated together. It does this by converting relative paths to absolute paths to avoid issues where a relative path becomes invalid following aggregation of the CSS file.

Parameters:

cssPath - The path of the CSS file being aggregated.

cssContents - The contents of the CSS file being aggregated.

Throws:

IOException

processCssImports

public StringBuffer processCssImports(String cssPath,
                             String fileContents,
                             Set<String> processedPaths)

When aggregating CSS files together its important to process any import statements that are included. The rules of CSS imports are that they must occur before anything else in the CSS file (even comments!) so we need to make sure that all imports are expanded to become the imported file contents TODO: It would be worth looking into caching processed CSS files.

Parameters:

cssPath - String

fileContents - String

processedPaths - Set

Returns:

StringBuffer

processCssImport

protected String processCssImport(String importContents,
                      String cssPath,
                      String importPath,
                      Set<String> processedPaths)
                           throws IOException

Processes a single CSS import request. This method ensures that infinite loops do not occur. The functionality has been abstracted to a separate method so that it can be called when either in debug or production modes.

Parameters:

importContents - The current contents of the CSS file being processed.

cssPath - The current path of the CSS file being processed.

importPath - The path requested to be imported within the current CSS file being processed.

processedPaths - A Set of the paths already processed.

Returns:

The processed CSS contents

Throws:

IOException

compressJavaScript

public String compressJavaScript(Reader reader)
                          throws IOException

Compresses the JavaScript file provided by the supplied InputStream using the YUI JavaScriptCompressor.

Parameters:

reader - Reader

Returns:

A String representation of the compressed JavaScript file

Throws:

IOException

compressCSSFile

public String compressCSSFile(InputStream in)
                       throws IOException

Compresses the CSS file provided by the supplied InputStream using the YUI CssCompressor.

Parameters:

in - InputStream

Returns:

A String representation of the compressed CSS file

Throws:

IOException

excludeFileFromCompression

public boolean excludeFileFromCompression(String path)

Checks to see whether or not the path meets any of the compression exclusion criteria. This can be used to prevent attempts to re-compress already compressed files or prevent attempts to compress files that are known to fail under compression.

Parameters:

path - The path to check against the filters

Returns:

true if the path should be excluded and false otherwise.

setCharset

public void setCharset(String charset)

setLinebreak

public void setLinebreak(int linebreak)

setMunge

public void setMunge(boolean munge)

setVerbose

public void setVerbose(boolean verbose)

setPreserveAllSemiColons

public void setPreserveAllSemiColons(boolean preserveAllSemiColons)

setDisableOptimizations

public void setDisableOptimizations(boolean disableOptimizations)