This is what the Environment service, and the @Environmental annotation, is for.
An outer component can store an object into the service, and nested components can pull the object back out (using the object type, typically an interface, as the key). For example, BeanEditForm stores an environmental value that identifies the type of property being editted, along with methods to read and set the property value (and a couple of other things). Components that render inside the BeanEditForm (even those that are dragged in from other pages), have access to that object. Parametes are merely the most common and convienient way for different objects (including components) to share information, but far from the only one. On 6/22/07, Doug Hauge <[EMAIL PROTECTED]> wrote:
Is there a way to pass a parameter from an outer component to a deeply nested inner component without having to explicitly pass the parameter to all intervening components? Basically, we have a parameter, 'node', whose value is calculated at the page level when handling the 'activate' event from the activation parameters. Suppose we have components 'A', 'B', 'C', 'D', where the page references 'A', 'A' references 'B', 'B' references 'C', and 'C' references 'D'. Component 'D' needs the value of 'node', but 'A', 'B', and 'C' don't, so we would like to avoid having to declare the 'node' parameter in those intervening components and passing the value in explicitly. I can't seem to find a way to do this. I have considered 1) Creating a service for calculating the code, but the calculation requires page parameters, and I can't think of a way to access to these from a service builder method (outside of nasty hacks like setting the value in a thread local variable). 2) Creating a new parameter binding factory that traverses up component containers until it finds one that has the named binding. However, 'ComponentResources' can get a binding type and see if a parameter is bound, but it does not provide access to the parameter binding itself. 'InternalComponentResources' provides read and write access to the parameter, but we aren't supposed to use internal services. Am I missing something? --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
-- Howard M. Lewis Ship TWD Consulting, Inc. Independent J2EE / Open-Source Java Consultant Creator and PMC Chair, Apache Tapestry Creator, Apache HiveMind Professional Tapestry training, mentoring, support and project work. http://howardlewisship.com --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
