    001// Copyright 2012 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.dom.Document;
    019import org.apache.tapestry5.dom.Element;
    020import org.apache.tapestry5.services.MarkupRenderer;
    021import org.apache.tapestry5.services.MarkupRendererFilter;
    022import org.apache.tapestry5.services.RequestGlobals;
    023
    024/**
    025 * Injects a {@code <meta/>} element into the {@code <head/>} to identify the Tapestry page name.
    026 * This filter is only active during development, not production.
    027 *
    028 * @since 5.4
    029 */
    030public class PageNameMetaInjector implements MarkupRendererFilter
    031{
    032    private final RequestGlobals globals;
    033
    034    public PageNameMetaInjector(RequestGlobals globals)
    035    {
    036        this.globals = globals;
    037    }
    038
    039    public void renderMarkup(MarkupWriter writer, MarkupRenderer delegate)
    040    {
    041        delegate.renderMarkup(writer);
    042
    043        String pageName = globals.getActivePageName();
    044
    045        Document document = writer.getDocument();
    046
    047        Element element = document.find("html/head");
    048
    049        if (element != null)
    050        {
    051            element.element("meta",
    052                    "name", "tapestry-page-name",
    053                    "content", pageName);
    054        }
    055
    056    }
    057}