001// Copyright 2007-2013 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.services;
016
017import org.apache.tapestry5.MarkupWriter;
018
019/**
020 * Filter interface for {@link org.apache.tapestry5.services.MarkupRenderer}, which allows for code to execute before
021 * and/or after the main rendering process. Typically, this is to allow for the placement of
022 * {@linkplain org.apache.tapestry5.services.Environment environmental services}.
023 * 
024 * @see org.apache.tapestry5.modules.TapestryModule#contributeMarkupRenderer
025 */
026public interface MarkupRendererFilter
027{
028    /**
029     * Implementations should perform work before or after passing the writer to the renderer.
030     * 
031     * @param writer
032     *            to which markup should be written
033     * @param renderer
034     *            delegate to which the writer should be passed.
035     */
036    void renderMarkup(MarkupWriter writer, MarkupRenderer renderer);
037}