com.bea.p13n.content
Class ContentCache

java.lang.Object
  |
  +--com.bea.p13n.content.ContentCache

public class ContentCache

extends java.lang.Object

implements javax.servlet.http.HttpSessionBindingListener, java.io.Serializable

An object to help with caching content.

This object can placed anywhere for use as a cache. For convience, the getContentCache method can be used with a JSP PageContext to create and utilize ContentCaches.

Additionally, this is what the <cm:select> and <cm:selectById> tags use when useCache="true".

See Also:

Serialized Form

Field Summary

protected java.util.Map	cache The cache of id to ContentHolder.
static java.lang.String	DEF_CACHE_NAME The default name of the ContentCache in the various locations ("wlps.content.cache").
protected long	flushFinishTime Cache flush finish time
protected static long	flushRequestTime Time of lastest request for flush contentCache with session/application scope
static java.lang.String	SESSION_NAME Deprecated. Use DEF_CACHE_NAME instead.

Constructor Summary

ContentCache()
Constructor.

Method Summary

static void	bindToSession(ContentCache cache, javax.servlet.http.HttpSession session) Bind a ContentCache into an HttpSession.
void	clear() Clear the entire cache.
static void	flush() Request flushing session/application scoped cache
static java.lang.Object	getAttribute(javax.servlet.jsp.PageContext ctx, java.lang.String name, int scope) Get a scoped attribute correctly from the JSP page context.
long	getCachedTime(java.lang.String id) Get the UTC time (in ms.) of when the Content at id was cached.
java.util.List	getCacheIds() Get an unordered list of all the cache ids.
long	getCacheSize() Get the total number of Content objects cached (across all ids).
Content[]	getContent(java.lang.String id, long timeout) Check the cache for the content.
static ContentCache	getContentCache(javax.servlet.jsp.PageContext ctx, int scope, boolean create) Get a ContentCache from the specified JSP context.
static ContentCache	getContentCache(javax.servlet.jsp.PageContext ctx, java.lang.String scopeStr, boolean create) Get a ContentCache from the specified JSP context.
protected ContentCache	getCurrentCache() No synchronize this method, since clear() is synchronized and concurrent accessing "flushRequestTime" and "flushFinishTime" only effect page layer cache for a short period of time.
static ContentCache	getFromSession(javax.servlet.http.HttpSession session, boolean create) Get a ContentCache from an HttpSession.
int	getNumCacheIds() Get the number of cache ids in the cache.
static java.lang.String	getScopeName(int scope) Get the scope name based upon the scope id.
Content[]	remove(java.lang.String id) Clear a particular entry from the cache.
static void	removeAttribute(javax.servlet.jsp.PageContext ctx, java.lang.String name, int scope) Remove a scoped attribute correctly from the JSP page context.
static void	setAttribute(javax.servlet.jsp.PageContext ctx, java.lang.String name, java.lang.Object val, int scope) Set a scoped attribute correctly in the JSP page context.
void	update(java.lang.String id, Content[] content) Update the cache with the content.
void	valueBound(javax.servlet.http.HttpSessionBindingEvent evt) Called when we're bound into an HttpSession.
void	valueUnbound(javax.servlet.http.HttpSessionBindingEvent evt) Called when we're unbound from an HttpSession, and clears the cache.

Methods inherited from class java.lang.Object

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

Field Detail

DEF_CACHE_NAME

public static final java.lang.String DEF_CACHE_NAME

The default name of the ContentCache in the various locations ("wlps.content.cache").

When the getContentCache method is used, this is the name which will used.

SESSION_NAME

public static final java.lang.String SESSION_NAME

Deprecated. Use DEF_CACHE_NAME instead.

The old name of the ContentCache.

This is set to DEF_CACHE_NAME.

cache

protected java.util.Map cache

The cache of id to ContentHolder.

flushRequestTime

protected static long flushRequestTime

Time of lastest request for flush contentCache with session/application scope

flushFinishTime

protected long flushFinishTime

Cache flush finish time

Constructor Detail

ContentCache

public ContentCache()

Constructor.

Method Detail

getContent

public Content[] getContent(java.lang.String id,
                            long timeout)

Check the cache for the content.

Getting content from the cache does not update its time in terms of a timeout. Only using the update(java.lang.String, com.bea.p13n.content.Content[]) method to update the cache will do that.

Parameters:

id - the cache id of the content.

timeout - the timeout in ms. for the content (less than 0 for no timeout).

Returns:

the array of Content, or null if not found or has timed out.

getCachedTime

public long getCachedTime(java.lang.String id)

Get the UTC time (in ms.) of when the Content at id was cached.

Parameters:

id - the cache id of the content.

Returns:

the time, or -1 if id is not a valid cache id.

getNumCacheIds

public int getNumCacheIds()

Get the number of cache ids in the cache.

getCacheIds

public java.util.List getCacheIds()

Get an unordered list of all the cache ids.

Since the keys will all be Strings, this can be sorted with Collections.sort(java.util.List).

getCacheSize

public long getCacheSize()

Get the total number of Content objects cached (across all ids).

update

public void update(java.lang.String id,
                   Content[] content)

Update the cache with the content.

This can be used for new or existing content in the cache.

Parameters:

id - cache id of the content.

content - the Content (null to remove).

remove

public Content[] remove(java.lang.String id)

Clear a particular entry from the cache.

Parameters:

id - the cache id of the content.

Returns:

the cached Content at the id, or null if none.

clear

public void clear()

Clear the entire cache.

valueBound

public void valueBound(javax.servlet.http.HttpSessionBindingEvent evt)

Called when we're bound into an HttpSession.

Specified by:

valueBound in interface javax.servlet.http.HttpSessionBindingListener

valueUnbound

public void valueUnbound(javax.servlet.http.HttpSessionBindingEvent evt)

Called when we're unbound from an HttpSession, and clears the cache.

Specified by:

valueUnbound in interface javax.servlet.http.HttpSessionBindingListener

See Also:

clear()

bindToSession

public static void bindToSession(ContentCache cache,
                                 javax.servlet.http.HttpSession session)

Bind a ContentCache into an HttpSession.

This will use DEF_CACHE_NAME as the session attribute name for the cache.

Parameters:

cache - the content cache object.

session - the http session.

getFromSession

public static ContentCache getFromSession(javax.servlet.http.HttpSession session,
                                          boolean create)

Get a ContentCache from an HttpSession.

This will retrieve the cache from the session attribute named DEF_CACHE_NAME. If that is set and is not a ContentCache, it will be removed.

Parameters:

session - the http session.

create - true to create a ContentCache if it's not there, false to not and return null.

Returns:

the cache if it exists or create was true, null if it didn't exist and create was false.

getContentCache

public static ContentCache getContentCache(javax.servlet.jsp.PageContext ctx,
                                           int scope,
                                           boolean create)

Get a ContentCache from the specified JSP context.

This will retrieve the ContentCache from the JSP context based upon the specified scope at the attribute named DEF_CACHE_NAME. If that is set and is not a ContentCache, it will be removed.

Parameters:

ctx - the JSP page context.

scope - the cache scope (one of PageContext.APPLICATION_SCOPE, PageContext.PAGE_SCOPE, PageContext.REQUEST_SCOPE, or PageContext.SESSION_SCOPE).

create - true to create a ContentCache if it's not there, false to not and return null.

Returns:

the cache if it exists or create was true, null if it didn't exist and create was false.

getContentCache

public static ContentCache getContentCache(javax.servlet.jsp.PageContext ctx,
                                           java.lang.String scopeStr,
                                           boolean create)

Get a ContentCache from the specified JSP context.

If scopeStr is "application", then PageContext.APPLICATION_SCOPE is used; if scopeStr is "page", then PageContext.PAGE_SCOPE is used; if scopeStr is "request", then PageContext.REQUEST_SCOPE is used; if scopeStr is "session", then PageContext.SESSION_SCOPE is used; otherwise, scopeStr is passed to ctx.getAttributesScope() which will determine the scope to use.

Parameters:

ctx - the JSP page context.

scopeStr - the scope name.

create - true to create a ContentCache if it's not there, false to not and return null.

Returns:

the cache if it exists or create was true, null if it didn't exist and create was false.

getAttribute

public static java.lang.Object getAttribute(javax.servlet.jsp.PageContext ctx,
                                            java.lang.String name,
                                            int scope)

Get a scoped attribute correctly from the JSP page context.

Parameters:

ctx - the JSP page context.

name - the attribute name.

scope - the attribute scope (PageContext.APPLICATION_SCOPE, PageContext.PAGE_SCOPE, PageContext.REQUEST_SCOPE, PageContext.SESSION_SCOPE).

setAttribute

public static void setAttribute(javax.servlet.jsp.PageContext ctx,
                                java.lang.String name,
                                java.lang.Object val,
                                int scope)

Set a scoped attribute correctly in the JSP page context.

Parameters:

ctx - the JSP page context.

name - the attribute name.

val - the attribute value.

scope - the attribute scope (PageContext.APPLICATION_SCOPE, PageContext.PAGE_SCOPE, PageContext.REQUEST_SCOPE, PageContext.SESSION_SCOPE).

removeAttribute

public static void removeAttribute(javax.servlet.jsp.PageContext ctx,
                                   java.lang.String name,
                                   int scope)

Remove a scoped attribute correctly from the JSP page context.

Parameters:

ctx - the JSP page context.

name - the attribute name.

scope - the attribute scope (PageContext.APPLICATION_SCOPE, PageContext.PAGE_SCOPE, PageContext.REQUEST_SCOPE, PageContext.SESSION_SCOPE).

getScopeName

public static java.lang.String getScopeName(int scope)

Get the scope name based upon the scope id.

flush

public static void flush()

Request flushing session/application scoped cache

getCurrentCache

protected ContentCache getCurrentCache()

No synchronize this method, since clear() is synchronized and concurrent accessing "flushRequestTime" and "flushFinishTime" only effect page layer cache for a short period of time. The impact can be ignored.