CmsFlexCacheEntry (Release 5.0.0)

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com.opencms.flex.cache
Class CmsFlexCacheEntry

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

All Implemented Interfaces:: I_CmsFlexLruCacheObject

public class CmsFlexCacheEntry
extends Object
implements I_CmsFlexLruCacheObject

Contains the contents of a cached resource.

It is basically a list of pre-generated output, include() calls to other resources (with request parameters) and http headers that this resource requires to be set.

A CmsFlexCacheEntry might also describe a redirect-call, but in this case nothing else will be cached.

The pre-generated output is saved in byte[] arrays. The include() calls are saved as Strings of the included resource name, the parameters for the calls are saved in a HashMap. The headers are saved in a HashMap. In case of a redirect, the redircet target is cached in a String.

The CmsFlexCacheEntry can also have a timeout value, which indicates the time that his entry will become invalid and should thus be cleared from the cache.

Version:: $Revision: 1.9 $
Author:: Alexander Kandzior (a.kandzior@alkacon.com), Thomas Weckert (t.weckert@alkacon.com)
See Also:: I_CmsFlexLruCacheObject

Field Summary

static int C_INITIAL_CAPACITY_LISTS
          Initial size for lists

Constructor Summary

CmsFlexCacheEntry()
          Constructor for class CmsFlexCacheEntry.

Method Summary

void add(byte[] bytes)
          Adds an array of bytes to this cache entry, this will usually be the result of some kind of output - stream.

void add(String resource, Map paramters)
          Add an include - call target resource to this cache entry.

void addHeaders(Map headers)
          Add a map of headers to this cache entry, which are usually collected in the class CmsFlexResponse first.

void addToLruCache()
          Invoked after an object was added to the cache.

void complete()
          Completes this cache entry.

List elements()
          Returns the list of data entries of this cache entry.

protected void finalize()
          Finalize this instance.

int getLruCacheCosts()
          Returns the cache costs of this object, as for example it's byte size.

I_CmsFlexLruCacheObject getNextLruObject()
          Returns the next object in the double linked list of all cached objects.

I_CmsFlexLruCacheObject getPreviousLruObject()
          Returns the previous object in the double linked list of all cached objects.

long getTimeout()
          Returns the timeout - value of this cache entry, this is set to the time when the entry becomes invalid.

void removeFromLruCache()
          Invoked after the object was removed to the cache.

void service(CmsFlexRequest req, CmsFlexResponse res)
          Processing method for this cached entry.

void setNextLruObject(I_CmsFlexLruCacheObject theNextEntry)
          Set the next object in the double linked list of all cached objects.

void setPreviousLruObject(I_CmsFlexLruCacheObject thePreviousEntry)
          Set the previous object in the double linked list of all cached objects.

void setRedirect(String target)
          Set a redirect target for this cache entry.

void setTimeout(long timeout)
          Sets a timeout value to this cache entry, which indicates the time this entry becomes invalid.

void setVariationData(String theVariationKey, Map theVariationMap)
          Stores a backward reference to the map and key where this cache entry is stored.

String toString()


Methods inherited from class java.lang.Object

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

Field Detail

C_INITIAL_CAPACITY_LISTS

public static final int C_INITIAL_CAPACITY_LISTS

Initial size for lists

See Also:: Constant Field Values

Constructor Detail

CmsFlexCacheEntry

public CmsFlexCacheEntry()

Constructor for class CmsFlexCacheEntry.

The way to use this class is to first use this empty constructor and later add data with the various add methods.

Method Detail

add

public void add(byte[] bytes)

Adds an array of bytes to this cache entry, this will usually be the result of some kind of output - stream.

Parameters:: bytes - the output to save in the cache

add

public void add(String resource,
                Map paramters)

Add an include - call target resource to this cache entry.

Parameters:: resource - a name of a resource in the OpenCms VFS

addHeaders

public void addHeaders(Map headers)

Add a map of headers to this cache entry, which are usually collected in the class CmsFlexResponse first.

Parameters:: headers - the map of headers to add to the entry

setRedirect

public void setRedirect(String target)

Set a redirect target for this cache entry.

Important: When a redirect target is set, all saved data is thrown away, and new data will not be saved in the cache entry. This is so since with a redirect nothing will be displayed in the browser anyway, so there is no point in saving the data.

Parameters:: target - The redirect target (must be a valid URL).

elements

public List elements()

Returns the list of data entries of this cache entry.

Data entries are byte arrays representing some kind of ouput or Strings representing include calls to other resources.

Returns:: the list of data elements of this cache entry

service

public void service(CmsFlexRequest req,
                    CmsFlexResponse res)
             throws CmsException,
                    javax.servlet.ServletException,
                    IOException

Processing method for this cached entry.

If this method is called, it delivers the contents of the cached entry to the given request / response. This includes calls to all included resources.

Parameters:: req - the request from the client; res - the server response
Throws:: CmsException - is thrown when problems writing to the response output-stream occur; ServletException - might be thrown from call to RequestDispatcher.include(); IOException - might be thrown from call to RequestDispatcher.include() or from Response.sendRedirect()

getTimeout

public long getTimeout()

Returns the timeout - value of this cache entry, this is set to the time when the entry becomes invalid.

Returns:: the timeout value for this resource

setTimeout

public void setTimeout(long timeout)

Sets a timeout value to this cache entry, which indicates the time this entry becomes invalid.

The timeout parameter represents the minute - intervall in which the cache entry is to be cleared. The intervall always starts at 0.00h. A value of 60 would indicate that this entry will reach it's timeout at the beginning of the next full hour, a timeout of 20 would indicate that the entry is invalidated at x.00, x.20 and x.40 of every hour etc.

Parameters:: timeout - the timeout value to be set

complete

public void complete()

Completes this cache entry.

A completed cache entry is made "unmodifiable", so that no further data can be added and existing data can not be changed. This is to prevend the (unlikley) case that some user-written class tries to make changes to a cache entry.

toString

public String toString()

Overrides:: toString in class Object

Returns:: a basic String representation of this CmsFlexCache entry
See Also:: Object.toString()

setVariationData

public void setVariationData(String theVariationKey,
                             Map theVariationMap)

Stores a backward reference to the map and key where this cache entry is stored. This is required for the FlexCache.

Parameters:: theVariationKey - the variation key; theVariationMap - the variation map