Package org.zkoss.zkmax.ui.util

Class DesktopRecycle

java.lang.Object

org.zkoss.zkmax.ui.util.DesktopRecycle

All Implemented Interfaces:

DesktopRecycle

public class DesktopRecycle
extends java.lang.Object
implements DesktopRecycle

Used to recycle the desktop if possible.

Available in ZK EE

If you want to recycle only particular paths, you could override shallCache(org.zkoss.zk.ui.Desktop, java.lang.String, int) and shallReuse(org.zkoss.zk.ui.Desktop, java.lang.String, int).

Since:

5.0.0

Author:

tomyeh

Constructor Summary

Constructors

Constructor	Description
DesktopRecycle()

Method Summary

Modifier and Type	Method	Description
void	afterRemove(Session sess, Desktop desktop)	Called after a desktop is removed.
void	afterService(Desktop desktop)	Called after the request is served.
boolean	beforeRemove(Execution exec, Desktop desktop, int cause)	Called when the client asks the server to remove a desktop because of the user's navigating to other URL or refreshing the page.
Desktop	beforeService(Execution exec, java.lang.String uri)	Called when an user requests the content of a page.
protected static java.lang.String	getURI(Desktop desktop)	Returns the request URI of the desktop.
protected java.util.Map	newCache(Session sess)	Instantiates the cache to hold the recycled desktop for the given session.
protected boolean	shallCache(Desktop desktop, java.lang.String uri, int cause)	Returns whether to cache the desktop of the specified URI, such that we can reuse it later.
protected boolean	shallExpunge(Desktop desktop, java.lang.String uri, int secElapsed)	Returns whether to remove it from the cache.
protected boolean	shallReuse(Desktop desktop, java.lang.String uri, int secElapsed)	Returns whether to re-use the cached desktop.

Methods inherited from class java.lang.Object

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

Constructor Detail

DesktopRecycle

public DesktopRecycle()

Method Detail

beforeRemove

public boolean beforeRemove(Execution exec,
                            Desktop desktop,
                            int cause)

Description copied from interface: DesktopRecycle

Called when the client asks the server to remove a desktop because of the user's navigating to other URL or refreshing the page.

The implementation can retrieve the request path by calling Desktop.getRequestPath().

Notice that, when the user refreshes a page, this method might be called after DesktopRecycle.beforeService(org.zkoss.zk.ui.Execution, java.lang.String) is called (depending on the browser and networking). In other words, there is no way it is a brand-new request from a new window, or it is caused by user's refreshing.

Specified by:

beforeRemove in interface DesktopRecycle

Parameters:

exec - the current execution.

cause - the cause. It is reserved for the future extension.

Returns:

whether to recycle the desktop. If true is returned, the desktop won't be removed. It is the implementation's job to remove it if necessary.

getURI

protected static java.lang.String getURI(Desktop desktop)

Returns the request URI of the desktop. It is a combination of Desktop.getRequestPath() and Desktop.getQueryString(). For example, if Desktop.getRequestPath() and Desktop.getQueryString() are "/foo.zul" and "abc=1", then this parameter is "/foo.zul?abc=1".

Since:

5.0.2

afterRemove

public void afterRemove(Session sess,
                        Desktop desktop)

Description copied from interface: DesktopRecycle

Called after a desktop is removed. A desktop is removed for different reasons, such as a session timeout, and too many desktops (when the memory is running low). In other words, some desktops are removed directly and only DesktopRecycle.afterRemove(org.zkoss.zk.ui.Session, org.zkoss.zk.ui.Desktop) is called.

The implementation has to remove the cached desktop, if any.

When this method is called, there might be no execution available (Executions.getCurrent() might return null).

Specified by:

afterRemove in interface DesktopRecycle

Parameters:

sess - the session that the desktop belongs to. Notice that Desktop.getSession() might be null when this method is called since it is destroyed.

desktop - the desktop to remove

beforeService

public Desktop beforeService(Execution exec,
                             java.lang.String uri)

Description copied from interface: DesktopRecycle

Called when an user requests the content of a page. To reuse a desktop, this method has to return the desktop to reuse.

Specified by:

beforeService in interface DesktopRecycle

Parameters:

exec - the execution. It doesn't not associated with a desktop, and used only for accessing the request and response.

uri - the request URI. It is a combination of Desktop.getRequestPath() and Desktop.getQueryString(). For example, if Desktop.getRequestPath() and Desktop.getQueryString() are "/foo.zul" and "abc=1", then this parameter is "/foo.zul?abc=1".

Returns:

the desktop to re-use. If null is returned, ZK Loader will create a desktop as if this interface is not installed.

afterService

public void afterService(Desktop desktop)

Description copied from interface: DesktopRecycle

Called after the request is served.

The implementation usually does nothing in this method, unless it wants to re-use it no matter if the same user might open two or more windows to visit the same URL.

When this method is called, there might be no execution available (Executions.getCurrent() might return null).

Specified by:

afterService in interface DesktopRecycle

newCache

protected java.util.Map newCache(Session sess)

Instantiates the cache to hold the recycled desktop for the given session.

Default: instantiate a hash map.

Since:

5.0.7

shallCache

protected boolean shallCache(Desktop desktop,
                             java.lang.String uri,
                             int cause)

Returns whether to cache the desktop of the specified URI, such that we can reuse it later.

The default implementation always return true. It means it tries to cache all paths.

If you want to cache only for, say, "/long-op/*", you can return true if path.startsWith("/long-op/").

Parameters:

uri - the request URI. It is a combination of Desktop.getRequestPath() and Desktop.getQueryString(). For example, if Desktop.getRequestPath() and Desktop.getQueryString() are "/foo.zul" and "abc=1", then this parameter is "/foo.zul?abc=1".

shallReuse

protected boolean shallReuse(Desktop desktop,
                             java.lang.String uri,
                             int secElapsed)

Returns whether to re-use the cached desktop.

The default implementation return true if the page was served in 10 minutes (600 seconds).

Parameters:

secElapsed - the number of seconds elapsed since the page was served.

shallExpunge

protected boolean shallExpunge(Desktop desktop,
                               java.lang.String uri,
                               int secElapsed)

Returns whether to remove it from the cache. It is called if shallReuse(org.zkoss.zk.ui.Desktop, java.lang.String, int) returns false.

Default: return true if the page was served more than 10 minutes ago (i.e., too old and we have to expunge it).

Since:

5.0.7