ZK Developer's Reference/MVC/Controller/Wire Variables

Wiring Sequence

GenericForwardComposer will wire members defined in the composer. Here is the sequence:

1. It searches any setters if its name matches any of the following
   1. Any fellow with the same name (Component.getFellow(String))
   2. Any variable defined in Page.addVariableResolver(VariableResolver) with the same name
   3. Any variable defined in zscript with the same name
   4. Any implicit object with the same name
2. Then, it searches any field to see if it matches any fellow, any variable,... the same as the above.

Wire Spring-managed Beans

Basically there are two approaches depending on whether you want to make the composer as a Spring-managed bean.

Approach 1: make the composer as a Spring-managed bean

If you prefer to manage composers with Spring, you could simply declare the Spring variable resolver called DelegatingVariableResolver in a ZUML document, and then use EL to retrieve the composer in the apply attribute. For example,

<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver"?>
<window apply="${passwordSetter}"> <!-- assume there is a Spring-managed bean called passwordSetter -->
...

As shown above, passwordSetter shall be a Spring-managed bean.

With this approach, since the composer will be instantiated by Spring, all the data member that Spring recognizes will be wired. Thus, you could access them directly. Because it is wired by Spring, you have to specify Spring's annotation accordingly.

mport org.springframework.beans.factory.annotation.Autowired;

public class PasswordSetter extends GenericFowardComposer {
    @Autowired
    private User user; //wired automatically by Spring
    private Textbox password; //wired automatically by ZK

    public void onClick$submit() {
        user.setPassword(password.getValue());
    }
}

Approach 2: have GenericForwardComposer to wire a String-managed bean

If you prefer not to have Spring to manage composers (for better separation or other reasons), you could register the Spring variable resolver manually as shown in the following code snippet.

Notice that the variable resolver will be checked when ZK wires a variable. Thus, if a data member's name matches a Spring-managed bean, it will be wired automatically too. For example,

public class PasswordSetter extends GenericFowardComposer {
    private User user; //wired automatically if user is a spring-managed bean
    private Textbox password; //wired automatically if there is a textbox named password

    public void doAfterComposer(Component comp) {
        page.addVariableResolver(new org.zkoss.zkplus.spring.DelegatingVariableResolver());
            //variable resolver must be added before calling super.doAfterCompose
            //since the autowiring depends on it
        super.doAfterCompose(comp);
    }
    public void onClick$submit() {
        user.setPassword(password.getValue());
    }
}

As shown, we could register the variable resolver in doAfterCompose by use of Page.addVariableResolver(VariableResolver).

zscript and Variable Resolver

By default, variables defined in both zscript and variable resolvers will be checked. There might be some performance penalty if you have too much zscript code, or your variable resolver is too slow.

You could turn them off by passing false to the second and third argument of GenericForwardComposer.GenericForwardComposer(char, boolean, boolean):

public class MyComposer extends GenericForwardComposer {
    public MyComposer() {
        super('$', false, false);
    }
}

Notice if you disable the wiring of EL variables (i.e., variables defined in a variable resolver), you can't wire the Spring-managed beans as described in the previous section.

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ID Space

For components that are inside of another ID space, you could use id1$id2$id3 to access it. More precisely, it will cause GenericForwardComposer to look for id1 in the same ID space as the applied component, and then look for, if found and it is another ID space, id2, and so on. For example, you could find the textbox by inner$input.

<window apply="foo.MyComposer">
   <window id="inner">
        <textbox id="input"/>
...

Here is another example: suppose have two ZUL files:

Main file	Included file - includeme.zul
<window id="mywindow" apply="MyComposer"> <include id="i" src="includeme.zul" /> </window>	<textbox id="username" />

To access the textbox "username" from "MyComposer", you could specify:

public class MyComposer extends GenericAutowireComposer {
    Textbox i$username;
    ...
}

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