Package org.zkoss.zk.ui.impl

Class UiEngineImpl

java.lang.Object

org.zkoss.zk.ui.impl.UiEngineImpl

All Implemented Interfaces:

UiEngine

public class UiEngineImpl
extends Object
implements UiEngine

An implementation of UiEngine to create and update components.

Author:

tomyeh

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	UiEngineImpl.Extension	An interface used to extend the UI engine.

Constructor Summary

Constructors

Constructor	Description
UiEngineImpl()

Method Summary

Modifier and Type	Method	Description
void	activate(Execution exec)	Activates an execution such that you can access a component.
boolean	activate(Execution exec, int timeout)	Activates an execution such that you can access a component.
void	addInvalidate(Component comp)	Invalidates a component to cause redrawing.
void	addInvalidate(Page page)	Invalidates the page to cause all of its components to redraw.
void	addMoved(Component comp, Component oldparent, Page oldpg, Page newpg)	Called to update (redraw) a component, when a component is moved.
void	addResponse(String key, AuResponse response)	Adds a response which will be sent to client at the end of the execution.
void	addResponse(String key, AuResponse response, int priority)	Adds a response with the given priority.
void	addResponse(AuResponse response)	Adds a response directly by using AuResponse.getOverrideKey() as the override key.
void	addSmartUpdate(Component comp, String attr, Object value, boolean append)	Smart-updates a property of the peer widget.
void	addSmartUpdate(Component comp, String attr, Object value, int priority)	Adds a smart update that will be executed at the given priority.
void	addUuidChanged(Component comp)	Called before changing the component's UUID.
protected void	afterRenderComponents(Collection<Component> comps)	Called when this engine renders the given components.
void	beginUpdate(Execution exec)	Activates and prepare for asynchronous update
boolean	ceaseSuspendedThread(Desktop desktop, EventProcessingThread evtthd, String cause)	Ceases the specified event thread.
void	clearSmartUpdate(Component comp)	Clears all existing smart updates that belong to the given component.
void	closeUpdate(Object ctx)	Deactivates the execution and cleans up.
Component[]	createComponents(Execution exec, PageDefinition pagedef, Page page, Component parent, Component insertBefore, org.zkoss.xel.VariableResolver resolver, Map<?,?> arg)	Creates components from the specified page and definition.
void	deactivate(Execution exec)	Deactivates an execution, such that other threads could activate and access components.
void	desktopDestroyed(Desktop desktop)	Called when a desktop is being removed.
boolean	disableClientUpdate(Component comp, boolean disable)	Sets whether to disable the update of the client widget.
void	endUpdate(Execution exec)	Executes posted events, deactivate and ends the asynchronous update.
void	execNewPage(Execution exec, PageDefinition pagedef, Page page, Writer out)	Creates components specified in the given page definition.
void	execNewPage(Execution exec, Richlet richlet, Page page, Writer out)	Invoke Richlet.service(org.zkoss.zk.ui.Page), when a new page is creates upon visiting a richlet.
void	execRecover(Execution exec, FailoverManager failover)	Executes the recovering.
void	execUpdate(Execution exec, List<AuRequest> requests, AuWriter out)	Executes an asynchronous update to a component (or page).
org.zkoss.json.JSONArray	finishUpdate(Object ctx)	Finishes the update and returns the result in an array of JSON object.
org.zkoss.json.JSONArray	finishUpdate(Object ctx, List<Throwable> errs)	Finishes the update and returns the result in an array of JSON object.
String	getNativeContent(Component comp, List<NodeInfo> children, Native.Helper helper)	Retrieve the native content for a property of the specified component.
Collection<EventProcessingThread>	getSuspendedThreads(Desktop desktop)	Returns a collection of suspended event processing threads belonging to the specified desktop, or empty if no suspended thread at all.
boolean	hasSuspendedThread()	Returns if any suspended event processing thread in the whole system.
boolean	isInvalidated(Component comp)	Returns if this component needs to be redrawn.
void	notify(Object mutex)	Wakes up a single event processing thread that is waiting on the specified object.
void	notify(Desktop desktop, Object mutex)	Wakes up a single event processing thread for the specified desktop that is waiting on the specified object.
void	notifyAll(Object mutex)	Wakes up all event processing thread that are waiting on the specified object.
void	notifyAll(Desktop desktop, Object mutex)	Wakes up all event processing threads for the specified desktop that are waiting on the specified object.
void	recycleDesktop(Execution exec, Page page, Writer out)	Reuse the desktop and generate the output.
void	sendRedirect(String uri, String target)	Sends a temporary redirect response to the client using the specified redirect location URL.
void	setAbortingReason(AbortingReason aborting)	Aborts the current execution.
Component	setOwner(Component comp)	Called before a component redraws itself if the component might include another page.
void	start(WebApp wapp)	Starts the engine.
Object	startUpdate(Execution exec)	Activates an execution that will allow developers to update the state of components.
void	stop(WebApp wapp)	Stops the engine.
void	wait(Object mutex)	Suspends the current processing of an event and wait until the other thread invokes UiEngine.notify(Object), UiEngine.notifyAll(Object), UiEngine.notify(Desktop, Object) or UiEngine.notifyAll(Desktop, Object) for the specified object.

Methods inherited from class java.lang.Object

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

Constructor Details

UiEngineImpl

public UiEngineImpl()

Method Details

start

public void start(WebApp wapp)

Description copied from interface: UiEngine

Starts the engine.

Specified by:

start in interface UiEngine

stop

public void stop(WebApp wapp)

Description copied from interface: UiEngine

Stops the engine. Called only if the server is about to stop.

Specified by:

stop in interface UiEngine

hasSuspendedThread

public boolean hasSuspendedThread()

Description copied from interface: UiEngine

Returns if any suspended event processing thread in the whole system.

Specified by:

hasSuspendedThread in interface UiEngine

getSuspendedThreads

public Collection<EventProcessingThread> getSuspendedThreads(Desktop desktop)

Description copied from interface: UiEngine

Returns a collection of suspended event processing threads belonging to the specified desktop, or empty if no suspended thread at all.

An event processing thread is an instance of EventProcessingThread

Specified by:

getSuspendedThreads in interface UiEngine

Parameters:

desktop - the desktop that the suspended event processing threads belong to (never null).

ceaseSuspendedThread

public boolean ceaseSuspendedThread(Desktop desktop,
 EventProcessingThread evtthd,
 String cause)

Description copied from interface: UiEngine

Ceases the specified event thread.

Specified by:

ceaseSuspendedThread in interface UiEngine

Parameters:

desktop - which desktop the event thread belongs to

cause - an arbitrary text to describe the cause. It will be the message of the thrown InterruptedException.

Returns:

true if the event processing thread is ceased successfully; false if no such thread or it is not suspended.

desktopDestroyed

public void desktopDestroyed(Desktop desktop)

Description copied from interface: UiEngine

Called when a desktop is being removed.

Application developers don't need to remove pages and desktops. They are removed and cleaned up automatically.

Specified by:

desktopDestroyed in interface UiEngine

setOwner

public Component setOwner(Component comp)

Description copied from interface: UiEngine

Called before a component redraws itself if the component might include another page.

If a new page is created, the specified component will become the owner of the new page.

It must reset the owner in the finally clause.

old = ue.setOwner(this);
try{
  ...
} finally {
  ue.setOwner(old);
}

Since 5.0.6, the owner must implement Includer.

Specified by:

setOwner in interface UiEngine

Returns:

the previous owner

isInvalidated

public boolean isInvalidated(Component comp)

Description copied from interface: UiEngine

Returns if this component needs to be redrawn.

Note:

1. It always returns true if the current execution is not an asynchronous update.
2. If its parent is invalidated, this component will be redrawn too, but this method returns false since UiEngine.addInvalidate(Component) was not called against this component.

Specified by:

isInvalidated in interface UiEngine

addInvalidate

public void addInvalidate(Page page)

Description copied from interface: UiEngine

Invalidates the page to cause all of its components to redraw.

Specified by:

addInvalidate in interface UiEngine

addInvalidate

public void addInvalidate(Component comp)

Description copied from interface: UiEngine

Invalidates a component to cause redrawing. Called when Component.invalidate() is called.

Specified by:

addInvalidate in interface UiEngine

addSmartUpdate

public void addSmartUpdate(Component comp,
 String attr,
 Object value,
 boolean append)

Description copied from interface: UiEngine

Smart-updates a property of the peer widget.

Specified by:

addSmartUpdate in interface UiEngine

append - whether to append the updates of properties with the same name. If false, only the last value of the same property will be sent to the client.

addSmartUpdate

public void addSmartUpdate(Component comp,
 String attr,
 Object value,
 int priority)

Description copied from interface: UiEngine

Adds a smart update that will be executed at the given priority. The higher priority, the earlier the update is executed. If UiEngine.addSmartUpdate(Component, String, Object, boolean) is invoked, the priority is assumed to 0.

If the priority is the same, the update is executed in the order of first-in-first out. You rarely need to control the sequence, unless the update is used to instantiate client-side widgets that other updates might depend on. In this case, it is suggested to specify the priority as 10000 (and not to use priority higher than 10000 for other situation).

Specified by:

addSmartUpdate in interface UiEngine

clearSmartUpdate

public void clearSmartUpdate(Component comp)

Description copied from interface: UiEngine

Clears all existing smart updates that belong to the given component.

Specified by:

clearSmartUpdate in interface UiEngine

addResponse

public void addResponse(AuResponse response)

Description copied from interface: UiEngine

Adds a response directly by using AuResponse.getOverrideKey() as the override key. In other words, it is the same as addResponse(resposne.getOverrideKey(), response)

If the response is component-dependent, AuResponse.getDepends() must return a component. And, if the component is removed, the response is removed, too.

Specified by:

addResponse in interface UiEngine

See Also:

• UiEngine.addResponse(String, AuResponse)

addResponse

public void addResponse(String key,
 AuResponse response)

Description copied from interface: UiEngine

Adds a response which will be sent to client at the end of the execution. Called by AbstractComponent.response(org.zkoss.zk.au.AuResponse).

Note: Execution.addAuResponse(org.zkoss.zk.au.AuResponse) is a shortcut to this method, and it is used by application developers.

If AuResponse.getDepends() is not null, the response depends on the returned component. In other words, the response is removed if the component is removed. If it is null, the response is component-independent.

Specified by:

addResponse in interface UiEngine

Parameters:

key - could be anything. If null, the response is appended. If not null, the second invocation of this method in the same execution with the same key and the same depends (AuResponse.getDepends()) will override the previous one.

See Also:

• UiEngine.addResponse(AuResponse)

addResponse

public void addResponse(String key,
 AuResponse response,
 int priority)

Description copied from interface: UiEngine

Adds a response with the given priority. The higher priority, the earlier the update is executed. The priority of UiEngine.addResponse(String, AuResponse) and UiEngine.addResponse(AuResponse) is assumed to be 0.

If the priority is the same, the update is executed in the order of first-in-first out.

Specified by:

addResponse in interface UiEngine

addMoved

public void addMoved(Component comp,
 Component oldparent,
 Page oldpg,
 Page newpg)

Description copied from interface: UiEngine

Called to update (redraw) a component, when a component is moved. If a component's page or parent is changed, this method need to be called only once for the top one.

Specified by:

addMoved in interface UiEngine

oldparent - the parent before moved

oldpg - the page before moved

newpg - the page after moved

addUuidChanged

public void addUuidChanged(Component comp)

Description copied from interface: UiEngine

Called before changing the component's UUID.

Specified by:

addUuidChanged in interface UiEngine

disableClientUpdate

public boolean disableClientUpdate(Component comp,
 boolean disable)

Description copied from interface: UiEngine

Sets whether to disable the update of the client widget. By default, if a component is attached to a page, modifications that change the visual representation will be sent to the client to ensure the consistency.

Specified by:

disableClientUpdate in interface UiEngine

Returns:

whether it has been disabled before this invocation, i.e., the previous disable status

execNewPage

public void execNewPage(Execution exec,
 Richlet richlet,
 Page page,
 Writer out)
                 throws IOException

Description copied from interface: UiEngine

Invoke Richlet.service(org.zkoss.zk.ui.Page), when a new page is creates upon visiting a richlet.

Specified by:

execNewPage in interface UiEngine

Throws:

IOException

execNewPage

public void execNewPage(Execution exec,
 PageDefinition pagedef,
 Page page,
 Writer out)
                 throws IOException

Description copied from interface: UiEngine

Creates components specified in the given page definition. Called when a new page is creates.

Specified by:

execNewPage in interface UiEngine

Throws:

IOException

recycleDesktop

public void recycleDesktop(Execution exec,
 Page page,
 Writer out)
                    throws IOException

Description copied from interface: UiEngine

Reuse the desktop and generate the output.

Specified by:

recycleDesktop in interface UiEngine

Throws:

IOException

afterRenderComponents

protected void afterRenderComponents(Collection<Component> comps)

Called when this engine renders the given components.

Parameters:

comps - the collection of components that have been redrawn.

createComponents

public Component[] createComponents(Execution exec,
 PageDefinition pagedef,
 Page page,
 Component parent,
 Component insertBefore,
 org.zkoss.xel.VariableResolver resolver,
 Map<?,?> arg)

Description copied from interface: UiEngine

Creates components from the specified page and definition. It can be called when UiEngine.execNewPage(org.zkoss.zk.ui.Execution, org.zkoss.zk.ui.metainfo.PageDefinition, org.zkoss.zk.ui.Page, java.io.Writer) or UiEngine.execUpdate(org.zkoss.zk.ui.Execution, java.util.List<org.zkoss.zk.au.AuRequest>, org.zkoss.zk.au.AuWriter) was called. It assumes the execution is already locked to this desktop.

Note: if both page and parent are null, the created components don't belong to any page/parent.

Specified by:

createComponents in interface UiEngine

Parameters:

exec - the execution (never null).

pagedef - the page definition (never null).

page - the page. Ignored if parent is specified and parent's page is not null (parent's page will be used). If both page and parent are null, the created components won't belong to any page.

parent - the parent component, or null if no parent component. If parent is specified, page is ignored.

insertBefore - the sibling component that new components will be inserted before. Ignored if null (i.e., append as last children).

resolver - the variable resolver used to resolve variables. Ignored if null.

arg - a map of parameters that is accessible by the arg variable in EL, or by Execution.getArg(). Ignored if null.

Returns:

the components being created.

sendRedirect

public void sendRedirect(String uri,
 String target)

Description copied from interface: UiEngine

Sends a temporary redirect response to the client using the specified redirect location URL.

After calling this method, the caller shall end the processing immediately (by returning). All pending requests and events will be dropped.

Specified by:

sendRedirect in interface UiEngine

Parameters:

uri - the URI to redirect to, or null to reload the same page

target - the new target, or null to denote the same browser window

setAbortingReason

public void setAbortingReason(AbortingReason aborting)

Description copied from interface: UiEngine

Aborts the current execution. if not null, it means the current execution is aborting

Note: if setAbortingReason is ever set with non-null, you CANNOT set it back to null.

After call this method, you shall not keep processing the page because the rendering is dropped and the client is out-of-sync with the server.

Specified by:

setAbortingReason in interface UiEngine

Parameters:

aborting - the aborting reason.

execRecover

public void execRecover(Execution exec,
 FailoverManager failover)

Description copied from interface: UiEngine

Executes the recovering.

Specified by:

execRecover in interface UiEngine

beginUpdate

public void beginUpdate(Execution exec)

Description copied from interface: UiEngine

Activates and prepare for asynchronous update

Specified by:

beginUpdate in interface UiEngine

endUpdate

public void endUpdate(Execution exec)
               throws IOException

Description copied from interface: UiEngine

Executes posted events, deactivate and ends the asynchronous update.

Specified by:

endUpdate in interface UiEngine

Throws:

IOException

execUpdate

public void execUpdate(Execution exec,
 List<AuRequest> requests,
 AuWriter out)
                throws IOException

Description copied from interface: UiEngine

Executes an asynchronous update to a component (or page). It is the same as execUpdate(exec, requests, null, out).

Note: the output must be XML and UTF-8.

Specified by:

execUpdate in interface UiEngine

requests - a list of AuRequest.

Throws:

IOException

startUpdate

public Object startUpdate(Execution exec)
                   throws IOException

Description copied from interface: UiEngine

Activates an execution that will allow developers to update the state of components.

It is designed to implement Bridge.

Specified by:

startUpdate in interface UiEngine

Returns:

a context that shall be passed to UiEngine.finishUpdate(java.lang.Object).

Throws:

IOException

See Also:

• UiEngine.finishUpdate(java.lang.Object)
• UiEngine.closeUpdate(java.lang.Object)

finishUpdate

public org.zkoss.json.JSONArray finishUpdate(Object ctx)
                                      throws IOException

Description copied from interface: UiEngine

Finishes the update and returns the result in an array of JSON object. Notice it does not deactivate the execution. Rather, the caller has to invoke UiEngine.closeUpdate(java.lang.Object).

It is designed to implement Bridge.

Specified by:

finishUpdate in interface UiEngine

Parameters:

ctx - the context returned by the previous call to UiEngine.startUpdate(org.zkoss.zk.ui.Execution)

Throws:

IOException

See Also:

• UiEngine.startUpdate(org.zkoss.zk.ui.Execution)
• UiEngine.closeUpdate(java.lang.Object)

finishUpdate

public org.zkoss.json.JSONArray finishUpdate(Object ctx,
 List<Throwable> errs)
                                      throws IOException

Description copied from interface: UiEngine

Finishes the update and returns the result in an array of JSON object. Notice it does not deactivate the execution. Rather, the caller has to invoke UiEngine.closeUpdate(java.lang.Object).

It is designed to implement Bridge.

Specified by:

finishUpdate in interface UiEngine

Parameters:

ctx - the context returned by the previous call to UiEngine.startUpdate(org.zkoss.zk.ui.Execution)

errs - the collection of errors if any.

Throws:

IOException

See Also:

• UiEngine.finishUpdate(Object)

closeUpdate

public void closeUpdate(Object ctx)
                 throws IOException

Description copied from interface: UiEngine

Deactivates the execution and cleans up.

It is designed to implement Bridge.

Specified by:

closeUpdate in interface UiEngine

Throws:

IOException

See Also:

• UiEngine.startUpdate(org.zkoss.zk.ui.Execution)
• UiEngine.finishUpdate(java.lang.Object)

wait

public void wait(Object mutex)
          throws InterruptedException,
SuspendNotAllowedException

Description copied from interface: UiEngine

Suspends the current processing of an event and wait until the other thread invokes UiEngine.notify(Object), UiEngine.notifyAll(Object), UiEngine.notify(Desktop, Object) or UiEngine.notifyAll(Desktop, Object) for the specified object.

It can only be called when the current thread is processing an event. And, when called, the current processing is suspended and ZK continues to process the next event and finally render the result.

It is typical use to implement a modal dialog where it won't return until the modal dialog ends.

Specified by:

wait in interface UiEngine

Parameters:

mutex - any non-null object to identify what to wait, such that UiEngine.notify(Object) and UiEngine.notify(Desktop, Object) knows which object to notify.

Throws:

SuspendNotAllowedException - if there are too many suspended exceptions. Deployers can control the maximal allowed number of suspended exceptions by specifying max-suspended-thread in zk.xml, or invoking Configuration.setMaxSuspendedThreads(int).

InterruptedException

notify

public void notify(Object mutex)

Description copied from interface: UiEngine

Wakes up a single event processing thread that is waiting on the specified object.

Unlike UiEngine.notify(Desktop, Object), this method can be invoked only if the same desktop is locked for processing requests.

Specified by:

notify in interface UiEngine

Parameters:

mutex - any non-null object to identify what to notify. It must be same object passed to UiEngine.wait(java.lang.Object).

See Also:

• UiEngine.notify(Desktop, Object)
• UiEngine.notifyAll(Object)

notify

public void notify(Desktop desktop,
 Object mutex)

Description copied from interface: UiEngine

Wakes up a single event processing thread for the specified desktop that is waiting on the specified object.

Unlike UiEngine.notify(Object), this method can be called any time. It is designed to let working threads resume an event processing thread.

Notice: if this method is NOT called in an event processing thread, the resumed thread won't execute until the next request is received. To enforce it happen, you might use the timer component (found in ZUL).

Specified by:

notify in interface UiEngine

Parameters:

desktop - the desktop which the suspended thread is processing. It must be the same desktop of the suspended thread.

mutex - any non-null object to identify what to notify. It must be same object passed to UiEngine.wait(java.lang.Object).

See Also:

• UiEngine.notify(Object)
• UiEngine.notifyAll(Desktop, Object)

notifyAll

public void notifyAll(Object mutex)

Description copied from interface: UiEngine

Wakes up all event processing thread that are waiting on the specified object.

Unlike UiEngine.notify(Desktop, Object), this method can be invoked only if the same desktop is locked for processing requests.

Specified by:

notifyAll in interface UiEngine

Parameters:

mutex - any non-null object to identify what to notify. It must be same object passed to UiEngine.wait(java.lang.Object).

See Also:

• UiEngine.notify(Desktop, Object)
• UiEngine.notifyAll(Object)

notifyAll

public void notifyAll(Desktop desktop,
 Object mutex)

Description copied from interface: UiEngine

Wakes up all event processing threads for the specified desktop that are waiting on the specified object.

Unlike UiEngine.notifyAll(Object), this method can be called any time. It is designed to let working threads resume an event processing thread.

If this method is NOT called in an event processing thread, the resumed thread won't execute until the next request is received. To enforce it happen, you might use the timer component (found in ZUL).

Specified by:

notifyAll in interface UiEngine

Parameters:

desktop - the desktop which the suspended thread is processing. It must be the same desktop of the suspended thread.

mutex - any non-null object to identify what to notify. It must be same object passed to UiEngine.wait(java.lang.Object).

See Also:

• UiEngine.notify(Object)
• UiEngine.notifyAll(Desktop, Object)

activate

public void activate(Execution exec)

Description copied from interface: UiEngine

Activates an execution such that you can access a component. You must call UiEngine.deactivate(org.zkoss.zk.ui.Execution) in the finally clause.

Note: you RARELY need to invoke this method because UiEngine.execNewPage(org.zkoss.zk.ui.Execution, org.zkoss.zk.ui.metainfo.PageDefinition, org.zkoss.zk.ui.Page, java.io.Writer) and UiEngine.execUpdate(org.zkoss.zk.ui.Execution, java.util.List<org.zkoss.zk.au.AuRequest>, org.zkoss.zk.au.AuWriter) will activate and deactivate automatically.

Note: this method can be called only when processing a client request (e.g., HTTP) other than creating a new page and processing async-update.

Also, even if you use this method to grant the right to access components of the specified page, don't post events, create, remove, invalidate and do any smart updates. In other words, READ ONLY.

Specified by:

activate in interface UiEngine

activate

public boolean activate(Execution exec,
 int timeout)

Description copied from interface: UiEngine

Activates an execution such that you can access a component. Unlike UiEngine.activate(Execution), you could specify an amount of time (timeout), and it returns false if it takes longer than the given amount of time before granted.

Specified by:

activate in interface UiEngine

timeout - the number of milliseconds to wait before giving up. It is ignored if negative, i.e., it waits until granted if negative.

Returns:

whether the activation succeeds

deactivate

public void deactivate(Execution exec)

Description copied from interface: UiEngine

Deactivates an execution, such that other threads could activate and access components.

Specified by:

deactivate in interface UiEngine

getNativeContent

public String getNativeContent(Component comp,
 List<NodeInfo> children,
 Native.Helper helper)

Description copied from interface: UiEngine

Retrieve the native content for a property of the specified component. The native content is a value of a property that is represented by a XML fragment (actually NativeInfo).

Example:

<html>
 <attribute name="content">
  <br/>
 </attribute>
</html>

Specified by:

getNativeContent in interface UiEngine

Parameters:

comp - the component that the native content will be assigned to. It is the object that the self variable is assigned when evaluating EL expressions.

children - a list of NativeInfo, TextInfo and others. This method evaluates them one-by-one and returns the result which is the value that will be assigned.

helper - the helper used to generate the content.

See Also:

• Property