com.opencms.flex.cache
Class CmsFlexCacheKey

java.lang.Object
  |
  +--com.opencms.flex.cache.CmsFlexCacheKey

public class CmsFlexCacheKey

extends Object

Implements the CmsFlexCacheKey, which is a key used to describe the caching behaviour of a specific resource.

It has a lot of "public" variables (which isn't good style, I know) to avoid method calling overhead (a cache is about speed, isn't it :).

Version:

$Revision: 1.7 $

Author:

Alexander Kandzior (a.kandzior@alkacon.com)

Field Summary

int	m_always Cache key variable: Determines if this resource can be cached alwys, never or under certain conditions. -1 = never, 0=check, 1=always
Set	m_groups Cache key variable: List of groups
Set	m_noparams Cache key variable: List of "blocking" parameters
Map	m_params Cache key variable: List of parameters
Set	m_ports Cache key variable: The request TCP/IP port
boolean	m_publish Cache key variable: Determines if the resource sould be always cleared at publish time
Set	m_schemes Cache key variable: Distinguishes request schemes (http, https etc.)
long	m_timeout Cache key variable: Timeout of the resource
String	m_uri Cache key variable: The uri of the original request
int	m_user Cache key variable: The user id
String	Resource The OpenCms resource that this key is used for.
String	Variation The cache behaviour description for the resource.

Constructor Summary

CmsFlexCacheKey(CmsFlexRequest request, String target, boolean online)
This constructor is used when building a cache key from a request.

CmsFlexCacheKey(String target, String cacheDirectives, boolean online)
This constructor is used when building a cache key from set of cache directives.

Method Summary

static String	getKeyName(String name, boolean online) Calculates the cache key name that is used as key in the first level of the FlexCache.
boolean	hadParseError() This flag is used to indicate that a parse error had occured, which can happen if the cache directives String passed to the constructor using the response is not build according to the Flex cache language syntax.
String	matchRequestKey(CmsFlexCacheKey key) Compares this key to the other key passed as parameter, from comparing the two keys, a variation String is constructed.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

Resource

public String Resource

The OpenCms resource that this key is used for.

Variation

public String Variation

The cache behaviour description for the resource.

m_always

public int m_always

Cache key variable: Determines if this resource can be cached alwys, never or under certain conditions. -1 = never, 0=check, 1=always

m_uri

public String m_uri

Cache key variable: The uri of the original request

m_user

public int m_user

Cache key variable: The user id

m_groups

public Set m_groups

Cache key variable: List of groups

m_params

public Map m_params

Cache key variable: List of parameters

m_noparams

public Set m_noparams

Cache key variable: List of "blocking" parameters

m_timeout

public long m_timeout

Cache key variable: Timeout of the resource

m_publish

public boolean m_publish

Cache key variable: Determines if the resource sould be always cleared at publish time

m_schemes

public Set m_schemes

Cache key variable: Distinguishes request schemes (http, https etc.)

m_ports

public Set m_ports

Cache key variable: The request TCP/IP port

Constructor Detail

CmsFlexCacheKey

public CmsFlexCacheKey(CmsFlexRequest request,
                       String target,
                       boolean online)

This constructor is used when building a cache key from a request.

The request contains several data items that are neccessary to construct the output. These items are e.g. the Query-String, the requested resource, the current time etc. etc. All required items are saved in the constructed cache - key.

Parameters:

target - the requested resource in the OpenCms VFS

online - must be true for an online resource, false for offline resources

request - the request to construct the key for

CmsFlexCacheKey

public CmsFlexCacheKey(String target,
                       String cacheDirectives,
                       boolean online)

This constructor is used when building a cache key from set of cache directives.

These directives are attached to the properties of the requested resource on a property called "cache". The value of this poperty that is passed in this constructor as "cacheDirectives" is parsed to build the keys data structure.

In case a parsing error occures, the value of this key is set to "cache=never", and the hadParseError() flag is set to true. This is done to ensure that a valid key is always constructed with the constructor.

Parameters:

target - the requested resource

cacheDirectives - the cache directives of the resource (value of the property "cache")

online - must be true for an online resource, false for offline resources

Method Detail

getKeyName

public static String getKeyName(String name,
                                boolean online)

Calculates the cache key name that is used as key in the first level of the FlexCache.

Parameters:

name - the name of the resource

online - must be true for an online resource, false for offline resources

Returns:

fhe FlexCache key name

hadParseError

public boolean hadParseError()

This flag is used to indicate that a parse error had occured, which can happen if the cache directives String passed to the constructor using the response is not build according to the Flex cache language syntax.

Returns:

true if a parse error did occur, false otherwise

matchRequestKey

public String matchRequestKey(CmsFlexCacheKey key)

Compares this key to the other key passed as parameter, from comparing the two keys, a variation String is constructed.

This method is the "heart" of the key matching process.

The assumtion is that this key should be the one constructed for the response, while the parameter key should have been constructed from the request.

A short example how this works: If the resource key is "cache=groups" and the request is done from a guest user (which always belongs to the default group "guests"), the constructed variation will be "groups=(guests)".

Parameters:

key - the key to match this key with

Returns:

null if not cachable, or the Variation String if cachable

toString

public String toString()

Overrides:

toString in class Object

Returns:

a complete String representation for this key

See Also:

Object.toString()