    001    // Copyright 2007, 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
    015    package org.apache.tapestry5.services;
    016
    017    import 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.services.TapestryModule#contributeMarkupRenderer
    025     */
    026    public 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    }