    001// Copyright 2007, 2008, 2009, 2011 The Apache Software Foundation
    002//
    003// Licensed under the Apache License, Version 2.0 (the "License");
    004// you may not use this file except in compliance with the License.
    005// You may obtain a copy of the License at
    006//
    007// http://www.apache.org/licenses/LICENSE-2.0
    008//
    009// Unless required by applicable law or agreed to in writing, software
    010// distributed under the License is distributed on an "AS IS" BASIS,
    011// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    012// See the License for the specific language governing permissions and
    013// limitations under the License.
    014
    015package org.apache.tapestry5.internal.services;
    016
    017import org.apache.tapestry5.MarkupWriter;
    018import org.apache.tapestry5.internal.structure.Page;
    019import org.apache.tapestry5.json.JSONObject;
    020import org.apache.tapestry5.runtime.RenderCommand;
    021import org.apache.tapestry5.services.PartialMarkupRendererFilter;
    022
    023/**
    024 * A wrapper around {@link org.apache.tapestry5.runtime.RenderQueue}, but referencable as a (per-thread) service. This
    025 * service is scoped so that we can tell it what to render in one method, then have it do the render in another. Part of
    026 * an elaborate scheme to keep certain interfaces public and other closely related ones private.
    027 */
    028public interface PageRenderQueue
    029{
    030    /**
    031     * Initializes the queue for rendering of a complete page.
    032     */
    033    void initializeForCompletePage(Page page);
    034
    035    /**
    036     * Sets the default page that will render the response.
    037     */
    038    void setRenderingPage(Page page);
    039
    040    /**
    041     * Returns the page that is rendering markup content.
    042     */
    043    Page getRenderingPage();
    044
    045    /**
    046     * Adds a rendering command to the queue of rendering commands. This must not be invoked until after
    047     * the {@linkplain #setRenderingPage(org.apache.tapestry5.internal.structure.Page) rendering page has been identified}.
    048     *
    049     * @param renderer responsible for rendering a portion of the final markup
    050     */
    051    void addPartialRenderer(RenderCommand renderer);
    052
    053    /**
    054     * Returns true if either {@link #addPartialRenderer(org.apache.tapestry5.runtime.RenderCommand)} or
    055     * {@link #addPartialMarkupRendererFilter(org.apache.tapestry5.services.PartialMarkupRendererFilter)}
    056     * has been invoked.
    057     */
    058    boolean isPartialRenderInitialized();
    059
    060    /**
    061     * Render to the markup writer, as setup by the {@link #initializeForCompletePage(org.apache.tapestry5.internal.structure.Page)} or
    062     * {@link #addPartialRenderer(org.apache.tapestry5.runtime.RenderCommand)} methods.
    063     *
    064     * @param writer to write markup to
    065     */
    066    void render(MarkupWriter writer);
    067
    068    /**
    069     * Performs a partial markup render, as configured via
    070     * {@link #addPartialRenderer(org.apache.tapestry5.runtime.RenderCommand)}.
    071     *
    072     * @param writer to which markup should be written
    073     * @param reply  JSONObject which will contain the partial response
    074     */
    075    void renderPartial(MarkupWriter writer, JSONObject reply);
    076
    077    /**
    078     * Adds an optional filter to the rendering. Optional filters are <em>temporary</em>, used just during the current
    079     * partial render (as opposed to filters contributed to the
    080     * {@link org.apache.tapestry5.services.PartialMarkupRenderer} service which are permanent, shared and stateless.
    081     * <p/>
    082     * Filters are added to the <em>end</em> of the pipeline (after all permanent contributions).
    083     * <p/>
    084     * Filters will be executed in the order in which they are added.
    085     *
    086     * @param filter to add to the pipeline
    087     */
    088    void addPartialMarkupRendererFilter(PartialMarkupRendererFilter filter);
    089}