Based on feedback from Imre and Ken, I've modified the proposal, below. Please read through this, as silence == consent. If there are no further comments, I'll enter this into the spec issue database, and the changes will probably be high on my queue for implementation in January. This change is intended to go into the MR. ----------------------------- Problem Description: PartialResponseWriter has very little JavaDoc or spec associated with it. Users are finding it difficult to use as a result. Additionally, the implicit call to startUpdate means that writing out other XML directives from a custom component is quite difficult. The JavaDoc preamble says: PartialResponseWriter decorates an existing ResponseWriter to support the generation of a partial response suitable for Ajax operations. In addition to the markup generation methods inherited from javax.faces.context.ResponseWriter, this class provides methods for constructing the standard partial response elements. The individual method summaries say such things as: void startUpdate(String targetId) Write the start of an update operation. And void startEval() Write the start of an eval operation. And void startDocument() Write the start of a partial response. Currently, what to do if you were to call a startXXX method while already in a startXXX function is unspecified. The spec (section 13.4.4.1) simply says: Writing The Partial Response JavaServer Faces provides javax.faces.context.PartialResponseWriter to ensure the Ajax response that is written follows the standard format as specified in Section 1.3 “XML Schema Definition for Partial Responses” Implementations must take care to properly handle nested CDATA sections when writing the response. PartialResponseWriter decorates an existing ResponseWriter implementation by extending javax.faces.context.ResponseWriterWrapper. Refer to the javax.faces.context.PartialResponseWriter JavaDocs, and the JavaScript documentation for the jsf.ajax.response function for more specifics. Proposal: We need to tighten up the spec in several ways: 1) Add comments to the JavaDoc that PartialResponseWriter will typically have startDocument and startUpdate called before the component can get hold of it. Note that this is to allow interoperability with components that are not instrumented for Ajax. 2) Expand description in 13.4.4.1 to describe that an error will be thrown if: startDocument is called more than once on a response. any method is called after endDocument. any method is called before startDocument 3) Add a description to the spec of what methods will typically be called before the client receives the PartialResponseWriter in RenderResponse. Describe when this is not so (render = @none). 4) Allow for the calling of other methods besides startUpdate within a normal component’s Render Response. a) I propose that we treat all calls to the following methods when within a startUpdate block as having their content placed on a queue, to be written out after the endUpdate is called: delete redirect startEval/endEval startUpdate/endUpdate startExtension/endExtension startInsertBefore/endInsert startInsertAfter/endInsert startError/endError updateAttributes b) for other (non-startUpdate) paired methods, calling any other method than the ending method is an error, and will raise an exception. c) unlimited nesting of startUpdates is allowed (though care should be taken, since significant memory can be consumed) - all queued writes that are made within that update block will be written out after the endUpdate is called, essentially writing things out depth first. 5) Update JavaDoc to indicated paired methods - startEval/endEval startUpdate/endUpdate startExtension/endExtension startInsertBefore/endInsert startInsertAfter/endInsert startError/endError It will be an error, and an exception will be thrown, to call one method without the other. Concluding statement: While the description of this behavior (in particular the queuing) may be a little difficult, I believe that this behavior most closely matches what users are expecting when they currently use the API. If this approach is accepted by the EG, I’ll write up the formal changes.