com.bea.content.manager.servlets
Class NodeCache

java.lang.Object
  com.bea.content.manager.servlets.NodeCache

All Implemented Interfaces:

EventListener, HttpSessionBindingListener, Serializable

public class NodeCache

extends Object

implements HttpSessionBindingListener, Serializable

An object to help with caching a Node or a array of Nodes.

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

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

See Also:

Serialized Form

Field Summary

static String	DEF_CACHE_NAME The default name of the NodeCache.
protected Map	nodeCache The cache to NodeHolder.

Constructor Summary

NodeCache()
Constructor.

Method Summary

static void	bindToSession(NodeCache cache, HttpSession session) Bind a NodeCache to an HttpSession.
void	clear() Clear the entire cache.
static Object	getAttribute(PageContext ctx, String name, int scope) Get a scoped attribute correctly from the JSP page context.
long	getCachedTime(String id) Get the UTC time (in ms.) of when the nodes at id were cached.
List	getCacheIds() Get an unordered list of all the cache ids.
long	getCacheSize() Get the total number of nodes objects cached (across all ids).
static NodeCache	getFromSession(HttpSession session, boolean create) Get a NodeCache from an HttpSession.
Node	getNode(String id, long timeout) Check the cache for the node.
static NodeCache	getNodeCache(PageContext ctx, int scope, boolean create) Get a NodeCache from the specified JSP context.
static NodeCache	getNodeCache(PageContext ctx, String scopeStr, boolean create) Get a NodeCache from the specified JSP context.
Node[]	getNodes(String id, long timeout) Check the cache for the nodes.
int	getNumCacheIds() Get the number of cache ids in the cache.
static String	getScopeName(int scope) Get the scope name based upon the scope id.
Node[]	remove(String id) Clear a particular entry from the cache.
static void	removeAttribute(PageContext ctx, String name, int scope) Remove a scoped attribute correctly from the JSP page context.
static void	setAttribute(PageContext ctx, String name, Object val, int scope) Set a scoped attribute correctly in the JSP page context.
void	update(String id, Node node) Update the cache with the Node.
void	update(String id, Node[] nodes) Update the cache with the nodes.
void	valueBound(HttpSessionBindingEvent evt) Called when we're bound into an HttpSession.
void	valueUnbound(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 String DEF_CACHE_NAME

The default name of the NodeCache.

When the getNodeCache(javax.servlet.jsp.PageContext, int, boolean) method is used, this is the name which will used.

See Also:

Constant Field Values

nodeCache

protected Map nodeCache

The cache to NodeHolder.

Constructor Detail

NodeCache

public NodeCache()

Constructor.

Method Detail

bindToSession

public static void bindToSession(NodeCache cache,
                                 HttpSession session)

Bind a NodeCache to an HttpSession.

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

Parameters:

cache - the nodes cache object.

session - the http session.

clear

public void clear()

Clear the entire cache.

getAttribute

public static Object getAttribute(PageContext ctx,
                                  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).

getCachedTime

public long getCachedTime(String id)

Get the UTC time (in ms.) of when the nodes at id were cached.

Parameters:

id - the cache id of the nodes.

Returns:

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

getCacheIds

public 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 nodes objects cached (across all ids).

getFromSession

public static NodeCache getFromSession(HttpSession session,
                                       boolean create)

Get a NodeCache from an HttpSession.

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

Parameters:

session - the http session.

create - true to create a NodeCache, 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.

getNode

public Node getNode(String id,
                    long timeout)

Check the cache for the node.

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

Parameters:

id - the cache id of the node.

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

Returns:

the Node, or null if not found or has timed out.

getNodeCache

public static NodeCache getNodeCache(PageContext ctx,
                                     int scope,
                                     boolean create)

Get a NodeCache from the specified JSP context.

This will retrieve the NodeCache from the JSP context based upon the specified scope at the attribute named DEF_CACHE_NAME. If that is set and is not a NodeCache 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 NodeCache 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.

getNodeCache

public static NodeCache getNodeCache(PageContext ctx,
                                     String scopeStr,
                                     boolean create)

Get a NodeCache 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 NodeCache 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.

getNodes

public Node[] getNodes(String id,
                       long timeout)

Check the cache for the nodes.

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

Parameters:

id - the cache id of the nodes.

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

Returns:

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

getNumCacheIds

public int getNumCacheIds()

Get the number of cache ids in the cache.

getScopeName

public static String getScopeName(int scope)

Get the scope name based upon the scope id.

remove

public Node[] remove(String id)

Clear a particular entry from the cache.

Parameters:

id - the cache id of the nodes.

Returns:

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

removeAttribute

public static void removeAttribute(PageContext ctx,
                                   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).

setAttribute

public static void setAttribute(PageContext ctx,
                                String name,
                                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).

update

public void update(String id,
                   Node node)

Update the cache with the Node.

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

Parameters:

id - cache id of the Node.

node - the Node (null to remove).

update

public void update(String id,
                   Node[] nodes)

Update the cache with the nodes.

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

Parameters:

id - cache id of the nodes.

nodes - the nodes (null to remove).

valueBound

public void valueBound(HttpSessionBindingEvent evt)

Called when we're bound into an HttpSession.

Specified by:

valueBound in interface HttpSessionBindingListener

valueUnbound

public void valueUnbound(HttpSessionBindingEvent evt)

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

Specified by:

valueUnbound in interface HttpSessionBindingListener

See Also:

clear()