org.w3c.jigsaw.filters
Class AccessLimitFilter

java.lang.Object
  org.w3c.tools.resources.AttributeHolder
      org.w3c.tools.resources.Resource
          org.w3c.tools.resources.FramedResource
              org.w3c.tools.resources.ResourceFrame
                  org.w3c.tools.resources.ResourceFilter
                      org.w3c.jigsaw.filters.AccessLimitFilter

All Implemented Interfaces:

java.lang.Cloneable, java.util.EventListener, AttributeChangedListener, FrameEventListener, FilterInterface

public class AccessLimitFilter
extends ResourceFilter

This filters limit the simultaneous accesses to its target resource.

Field Summary

protected static int	ATTR_LIMIT Attribute index - The maximum allowed simultaneous accesses.
protected static int	ATTR_TIMEOUT Attribute index - The time to wait for the lock (if limit reached)
protected int	count Current number of requets that have reached the target.

Fields inherited from class org.w3c.tools.resources.ResourceFrame

filterClass, frameListener, resource

Fields inherited from class org.w3c.tools.resources.FramedResource

ATTR_OID, attrListener, debugEvent, event_disabled, framesRef, structListener

Fields inherited from class org.w3c.tools.resources.Resource

ATTR_CONTEXT, ATTR_HELP_URL, ATTR_IDENTIFIER, ATTR_LAST_MODIFIED, ATTR_PARENT, ATTR_RESOURCE_FRAMES, ATTR_STORE_ENTRY, ATTR_URL, co, id

Fields inherited from class org.w3c.tools.resources.AttributeHolder

attributes, values

Constructor Summary

AccessLimitFilter()

Method Summary

int	getLimit() Get the maximum number of allowed simultaneous accesses.
int	getTimeout() Get the timeout before we send back an error.
ReplyInterface	ingoingFilter(RequestInterface req) Count number of hits to the page, block when limit exceeded.
ReplyInterface	outgoingFilter(RequestInterface req, ReplyInterface rep) Notify that someone has exit the target entity.

Methods inherited from class org.w3c.tools.resources.ResourceFilter

exceptionFilter, getTargetResource, ingoingFilter, initialize, lookup, outgoingFilter, outputFilter, pickleValues

Methods inherited from class org.w3c.tools.resources.ResourceFrame

addFrameEventListener, attributeChanged, checkRequest, eventDisabled, fireFrameEvent, frameModified, getFilters, getFilters, getFrameReference, getResource, getResourceReference, getSpaceEntry, getURLPath, lookupFilters, lookupFrames, perform, postFrameEvent, processEvent, registerResource, removeFrameEventListener, setValue, unregisterResource, updateDefaultChildAttributes

Methods inherited from class org.w3c.tools.resources.FramedResource

addAttributeChangedListener, addStructureChangedListener, collectFramesReference, delete, disableEvent, displayEvent, enableEvent, fireAttributeChangeEvent, fireStructureChangedEvent, fireStructureChangedEvent, frameAdded, frameRemoved, getClone, getFrame, getFrame, getFrameReference, getFrameReference, getFramesReference, getOid, initialize, markModified, notifyUnload, performFrames, postAttributeChangeEvent, postEvent, postStructureChangedEvent, postStructureChangedEvent, registerFrame, registerFrameIfNone, removeAttributeChangedListener, removeStructureChangedListener, setSilentValue, setSilentValue, unregisterFrame

Methods inherited from class org.w3c.tools.resources.Resource

acceptUnload, checkMultipleLock, collectFrames, getContext, getFrame, getFrames, getHelpURL, getHelpURL, getIdentifier, getLastModified, getParent, getServer, getSpace, getStoreEntry, getValue, getValue, isInitialized, isUnloaded, setContext, setContext, setValue, unsafeGetContext, unsafeGetFrame, unsafeGetFrames, unsafeGetIdentifier, unsafeGetResourceReference, unsafeGetURLPath, unsafeGetValue, updateAttributes

Methods inherited from class org.w3c.tools.resources.AttributeHolder

definesAttribute, definesAttribute, getAttributes, getBoolean, getChar, getClone, getClone, getDouble, getFloat, getInt, getLong, getString, getValue, lookupAttribute, print, setBoolean, setChar, setDouble, setFloat, setInt, setLong, setString, setValue, unsafeDefinesAttribute, unsafeGetDouble, unsafeGetString

Methods inherited from class java.lang.Object

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

Field Detail

ATTR_LIMIT

protected static int ATTR_LIMIT

Attribute index - The maximum allowed simultaneous accesses.

ATTR_TIMEOUT

protected static int ATTR_TIMEOUT

Attribute index - The time to wait for the lock (if limit reached)

count

protected int count

Current number of requets that have reached the target.

Constructor Detail

AccessLimitFilter

public AccessLimitFilter()

Method Detail

getLimit

public int getLimit()

Get the maximum number of allowed simultaneous accesses.

getTimeout

public int getTimeout()

Get the timeout before we send back an error. A client will wait only for this duration before being thrown an error.

ingoingFilter

public ReplyInterface ingoingFilter(RequestInterface req)
                             throws HTTPException

Count number of hits to the page, block when limit exceeded. This filter maintains the actual number of hits to its target. When this number exceeds the predefined limit, it blocks the caller until some othre thread exits the target.

Overrides:

ingoingFilter in class ResourceFilter

Parameters:

request - The request to be handled.

Returns:

A Reply instance, or null if processing should continue normally.

Throws:

HTTPException - if access limit is reached.

outgoingFilter

public ReplyInterface outgoingFilter(RequestInterface req,
                                     ReplyInterface rep)

Notify that someone has exit the target entity. This method decrements the actual number of hits to the filter's target, and notify any awaiting threads that they can now enter safely.

Overrides:

outgoingFilter in class ResourceFilter

Parameters:

request - The request being handled.

reply - The reply to be emited.

Returns:

A Reply instance, or null if processing should continue normally.