Package org.zkoss.zk.ui.util

Interface ComposerExt<T extends Component>

All Known Implementing Classes:

BindComposer, ClientBindComposer, GenericAutowireComposer, GenericComposer, GenericForwardComposer, SelectorComposer

public interface ComposerExt<T extends Component>

An addition interface implemented with Composer to provide more control.

Note: any class that implements ComposerExt must implement Composer, but not vice-versa.

Since:

3.0.0, Composer

Author:

tomyeh

See Also:

FullComposer

Method Summary

Modifier and Type	Method	Description
ComponentInfo	doBeforeCompose(Page page, Component parent, ComponentInfo compInfo)	Invokes before composing a component.
void	doBeforeComposeChildren(T comp)	Invokes after the component is instantiated and initialized, but before composing any child.
boolean	doCatch(java.lang.Throwable ex)	Called when an exception occurs when composing the component.
void	doFinally()	Called after the component has been composed completely.

Method Detail

doBeforeCompose

ComponentInfo doBeforeCompose(Page page,
                              Component parent,
                              ComponentInfo compInfo)
                       throws java.lang.Exception

Invokes before composing a component. If you want to manipulate the specified component info, you can use ComponentInfo.duplicate() to make a copy and then modify it such that it won't affect the default behavior.

Parameters:

page - the page for composing this component.

parent - the parent component, or null if it is the root component.

compInfo - the component info used to instantiate the component. Notice that it is null if the page is rendered as ZK JSP, since ComponentInfo is not available under ZK JSP.

Returns:

the component info used to instantiate the component. In most case, it shall return compInfo. If null is returned, the component won't be instantiated. In other words, it is ignored.

Throws:

java.lang.Exception

doBeforeComposeChildren

void doBeforeComposeChildren(T comp)
                      throws java.lang.Exception

Invokes after the component is instantiated and initialized, but before composing any child.

Parameters:

comp - the component being composed

Throws:

java.lang.Exception

doCatch

boolean doCatch(java.lang.Throwable ex)
         throws java.lang.Exception

Called when an exception occurs when composing the component.

If you don't want to handle the exception, simply returns false. boolean doCatch(Throwable ex) {return false;}

An exception thrown in this method is simply logged. It has no effect on the execution. If you want to ignore the exception, just return true.

Parameters:

ex - the exception being thrown

Returns:

whether to ignore the exception. If false is returned, the exception will be re-thrown. Note: once a composer's doCatch returns true, the exception will be ignored and it means doCatch of the following composers won't be called.

Throws:

java.lang.Exception

doFinally

void doFinally()
        throws java.lang.Exception

Called after the component has been composed completely. It is the last step of the composing.

Note: it is always called even if doCatch(java.lang.Throwable), doBeforeComposeChildren(T) or Composer.doAfterCompose(T) is not called (due to exceptions).

Note: it is called after the onCreate event is posted, but before the onCreate and any other events are handled.

An exception thrown in this method is simply logged. It has no effect on the execution.

Throws:

java.lang.Exception