I have a foreach element in my flow, which has a variable named "counter" set. Inside the foreach, I have a component, and I'm trying to get access to the "counter" variable from within the component. What is the proper way to get a hold of this variable from inside the component? Does it require adding a parameter to the method? I already have a parameter to take in the payload.
Any variable from the mule flow can be accessed inside a Component by using the
muleMessage.getInvocationProperty("counter");
muleMessage can be obtained from MuleEventContext of the onCall(MuleEventContext arg0) method. Assuming that you have implemented Callable interface of mule.
If not, try getting the message from org.mule.RequestContext.getEvent().getMessage()
This is RequestContext is deprecated as of now.
Hope this helps.
If we set the counter value in a property, we can get that property in inbound properties of message inside the component.
some thing like this
<set-variable variableName="counter" value="10" />
<set-property propertyName="testout" value="#[counter]" doc:name="Property" />
Thanks-
Related
I have one property file linked both ways (using f:loadBundle and faces-config.xml) both with different var names. So it would look like the following:
datatypes.properties:
A=first
B=second
C=third
faces-config.xml:
<resource-bundle>
<base-name>datatypes</base-name>
<var>myProp</var>
</resource-bundle>
myPage.xhtml:
<f:loadBundle basename="datatypes" var="prop"/>
in myPage.xhtml I make a list of all the keys from the property file. What I can't seem to understand is that when I use #{prop} in the code below it works but when I replace it with #{myProp} the list no longer displays.
<h:form>
<h:selectManyListbox id="list">
<f:selectItems value="#{myProp}"></f:selectItems>
</h:selectManyListbox>
</h:form>
I figure this means the variables in both cases are not the same behind the scenes but I would appreciate it if someone could explain (or point me to an explaination) in what way they are different. I would ideally like to just use #{myProp} without having to pull the keys out in code and store them in a list.
Thanks.
Both <f:loadBundle> and <resource-bundle> are different ways to load properties with difference being in their access scopes. The latter has by the way the additional benefit that the bundle is also injectable in a managed bean by #ManagedProperty("#{myProp}")
Using <resource-bundle> in faces-config.xml creates a global resource bundle which can be accessed anywhere in your application. This is implemented through a java.util.ResourceBundle instance.
Using <f:loadBundle> in your view creates a view-specific resource bundle which is accessible only within that view. The tag handler implements this using an internal implementation of a Map. This is as specified in the VDL of the tag:
Load a resource bundle localized for the Locale of the current view,
and expose it as a java.util.Map in the request attributes of the
current request under the key specified by the value of the "var"
attribute of this tag.
Now since you're trying to use the values from datatypes.properties through <f:selectItems>, you'll get the said exception. This is because the value attribute for the tag should evaluate to a Collection or an array.
Value expression pointing at any Collection or array. The member
elements may be instances of SelectItem or any Java Object.
So in order to use the global bundle instance, you first have to convert the same into a List<SelectItem> inside your backing bean before using it.
NOTE: You can verify the above cases by setting a breakpoint in the initializeItems(Object) method in the com.sun.faces.renderkit.SelectItemsIterator class. This is, of course, assuming that you're using the Mojarra implementation.
I followed the example here: Why does <h:inputText required="true"> allow blank spaces? to create a "Global" converter to trim all input fields. However, the converter is not being invoked when input fields are submitted.
#FacesConverter(forClass=String.class)
...
<p:inputText value="#{controller.inputValue}"/>
but when I change to:
#FacesConverter("StringTrimmer")
...
<p:inputText value="#{controller.inputValue}" converter="StringTrimmer"/>
it works.
Using Mojarra 2.1.7 and PrimeFaces 3.2
A converter with a forClass will only be invoked whenever the type of the property is an instance of the specified class. In your particular case, that can only mean that the #{controller.inputValue} is not of type String.
If you checked that the bound variable is of type String and the converter still doesn't get called, you may also check the following:
If the input component is encapsulated inside a composite component, you may have this issue. In that case, converters would not be called correctly, resulting in your custom method to be never reached. Calling the converter explicitly on the input component solves this.
If you add both value="someName" and forClass="someClass" to the #FacesConverter annotation, the forClass attribute will be ignored. This has been reported here.
This didnt work because the inputValue was not actually of type String. Once changed to type String-- it worked.
How does exactly the following code work:
#{aaa.id}
<h:inputText id="txt1" binding="#{aaa}"/>
I mean, usually the component binding works, by specifying a property (of type UIComponent) in a bean. Here, there's no bean nor property but nevertheless the name "aaa" gets bound correctly (displaying the component id - "txt1"). How does it work/where is it specified?
Thanks
UPDATE: The JSF2.0 Spec [pdf] (Chapter 3.1.5) says:
"A component binding is a special value expression that can be used to facilitate “wiring up” a component instance to a
corresponding property of a JavaBean... The specified ValueExpression must point to a read-write JavaBeans property of type UIComponent (or
appropriate subclass)."
It's been put in the default EL scope during building of the view tree (that's when all binding attributes -- and attributes of tag handlers like JSTL <c:xxx> and JSF <f:xxx> -- are being evaluated). It's being shown by normal EL means during rendering of the view tree. Rendering of the view tree happens after building of the view tree, so it works that way. It's not that this code runs "line by line" as you seemed to expect from the source.
I can't point you out a single reference where it's been specified as there is none. You'd have to read both the EL spec and JSF spec separately and do a 1+1=2.
By the way, to avoid confusion among new developers and to avoid clashes with existing variables in the EL scopes, you can use a java.util.HashMap in the request scope which is been declared as follows in faces-config.xml:
<managed-bean>
<description>Holder of all component bindings.</description>
<managed-bean-name>components</managed-bean-name>
<managed-bean-class>java.util.HashMap</managed-bean-class>
<managed-bean-scope>request</managed-bean-scope>
</managed-bean>
and is been used as follows
#{components.aaa.id}
<h:inputText id="txt1" binding="#{components.aaa}"/>
which is more self-documenting.
See also:
How does the 'binding' attribute work in JSF? When and how should it be used?
[Bindable]
/**
* Display output of video device.
*/
public var videoLocal : Video;
Anyone knows?
[Bindable] is a one of several meta tags that you can use in flex ActionScript code. It can be applied to properties, or methods that are marked in any scope. It cannot be used with static class members.
The key to using the [Bindable] meta tag is understanding what is going on under the hood when you use it. Essentially using data binding is a type of shorthand for adding event listeners and dispatching events.
There are two basic forms of the [Bindable] tag. The first is just [Bindable] followed by a var/property declaration. The Second is [Bindable(event="eventname")] followed by either a var/property declaration, a function/method declaration or one half of a getter/setter declaration.
I'll explain the longer notation first since the other builds on the same concept but with even more shorthand.
When you use [Bindable(event="eventname")] you are essentially telling the compiler that this var/property/function/method (call this the instance member) is 'available' to be used as the source for data binding. You are also telling it that when the value of the instance member has been invalidated/changed and it needs to be re-read that the "eventname" event will be dispatched.
In this longer form this all you are doing. You the developer are responsible for actually dispatching the "eventname" event whenever the value needs to be updated in the binding subscribers.
The real efficiency of using data binding comes on the subscribing side. The typical notation you will see in MXML is value="{instance.propertyName}" When you use the notation { } you are telling the compiler to do the following:
Create an event listener that listens to the event named in the bindable meta tag
In that event listener re-read the instance.propertyName and update this value
If you use the shorter form [Bindable], and you add the tag before a property/var, the compiler fills in the blanks and adds some additional functionality to make the property bindable. Essentially you are telling the compiler "add the events and methods you need to make this property bindable"
Now the way to think of what the compiler will do under the hood is this.
make a private version of your var
create an "event" to trigger the binding
create a getter function with scope and name of your original var that returns the private verson of the var when called.
create a setter function with scope and name of your original var that sets the private version of the var when called AND dispatches the triggering event.
In essence the compiler will do much of the work for you.
[Bindable]
public var xyz
is equivalent to
private var _xyz:String;
[Bindable(event="updateXYZValue")]
public function get xyz():String{
return _xyz;
}
public function set xyz(newxyz:String):void{
_xyz = newxyz;
dispatchEvent(new Event("updateXYZValue"));
}
The only functional differences in these is that in the first instance;
you do not know the name of the event that will be dispatched to trigger the binding
there is no way to update the underlying value without triggering the data binding
This second example also demonstrates one special case of the [Bindable] meta tag. This is that when you are applying it to a getter/setter pair defined for the same variable name you need only apply it to one or the other, it will apply to both. Typically you should set it on the getter.
You can use either notation on a function/method however if you do not specify an event the binding will never be triggered so if you are trying to bind to a function you should alway specify an event. It is also possible to specify more than one triggering event by stacking the tag. eg.
[Bindable(event="metaDataChanged")]
[Bindable(event="metaObjectUpdated")]
public function readMyMetaData():MetaDataObject{
var myMetaDataObject:MetaDataObject;
.
.
.
return myMetaDataObject;
}
This would presume that somewhere else you your class you will dispatch this metaDataChanged event or the metaObjectUpdated event when you want trigger the binding.
Also note that with this notation you can tie the binding of any instance member to any event that the instance will dispatch. Even inherited events that you yourself do not generate such as FrameEnter, OnChange, etc...
Data bindings can also be setup and destroyed during runtime. If you are interested in this take a look at the mx.binding.utils classes.
It is used in Databinding with Flex, you can read more about it here
http://livedocs.adobe.com/flex/3/html/help.html?content=databinding_2.html
Creating properties to use as the source for data binding
When you create a property that you
want to use as the source of a data
binding expression, Flex can
automatically copy the value of the
source property to any destination
property when the source property
changes. To signal to Flex to perform
the copy, you must use the [Bindable]
data tag to register the property with
Flex.
As an addition to what Justin said, you can actually use two ways data binding in Flex with the # character. Here's an example:
<s:TextInput id="txt1" text="#{txt2.text}" />
For a working example with source code enabled you can check out this article I wrote a while back:
Two-ways data binding in Flex
Is it possible to put a placeholder for a method call in the property value of an object in the Object Inspector? I have a method that returns a string that I'd like to include as part of the connection-string properties of some TADOConnection objects. Changing the method's return value would alter what gets assigned to each of the connections as they're loaded from the DFM.
I'm using RAD Studio 2010.
No, you cant. You can only have properties and events, but:
You can create a set method in you Connection property. This set method you search all forms and datamodules in you application and it will try to find an TADOConnection. When it finds one, it willl change its connection property. But this will only works in design time in the current form you put your component into, but it would work fine on runtime. Thats is not a pleasent solution, maybe you should try what #TommyA said on comments.