    001package org.apache.turbine.services.template;
    002
    003/*
    004 * Licensed to the Apache Software Foundation (ASF) under one
    005 * or more contributor license agreements.  See the NOTICE file
    006 * distributed with this work for additional information
    007 * regarding copyright ownership.  The ASF licenses this file
    008 * to you under the Apache License, Version 2.0 (the
    009 * "License"); you may not use this file except in compliance
    010 * with the License.  You may obtain a copy of the License at
    011 *
    012 *   http://www.apache.org/licenses/LICENSE-2.0
    013 *
    014 * Unless required by applicable law or agreed to in writing,
    015 * software distributed under the License is distributed on an
    016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    017 * KIND, either express or implied.  See the License for the
    018 * specific language governing permissions and limitations
    019 * under the License.
    020 */
    021
    022import java.util.Hashtable;
    023
    024/**
    025 * This is the interface that all template engine services must adhere
    026 * to. This includes the Velocity, WebMacro, FreeMarker, and JSP
    027 * services.
    028 *
    029 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
    030 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
    031 * @version $Id: TemplateEngineService.java 1706239 2015-10-01 13:18:35Z tv $ */
    032public interface TemplateEngineService
    033{
    034    /** Configuration key */
    035    String TEMPLATE_EXTENSIONS = "template.extension";
    036    /** Configuration key */
    037    String DEFAULT_TEMPLATE_EXTENSION = "template.default.extension";
    038    /** Configuration key */
    039    String DEFAULT_PAGE = "default.page";
    040    /** Configuration key */
    041    String DEFAULT_SCREEN = "default.screen";
    042    /** Configuration key */
    043    String DEFAULT_LAYOUT = "default.layout";
    044    /** Configuration key */
    045    String DEFAULT_NAVIGATION = "default.navigation";
    046    /** Configuration key */
    047    String DEFAULT_ERROR_SCREEN = "default.error.screen";
    048    /** Configuration key */
    049    String DEFAULT_LAYOUT_TEMPLATE = "default.layout.template";
    050    /** Configuration key */
    051    String DEFAULT_SCREEN_TEMPLATE = "default.screen.template";
    052    /** Configuration key */
    053    String DEFAULT_NAVIGATION_TEMPLATE = "default.navigation.template";
    054
    055    /**
    056     * Return the configuration of the template engine in
    057     * the form of a Hashtable.
    058     * @return the template engine service configuration map
    059     */
    060    Hashtable<String, Object> getTemplateEngineServiceConfiguration();
    061
    062    /**
    063     * Initializes file extension associations and registers with the
    064     * template service.
    065     *
    066     * @param defaultExt The default file extension association to use
    067     *                   in case of properties file misconfiguration.
    068     */
    069    void registerConfiguration(String defaultExt);
    070
    071    /**
    072     * Supplies the file extension to key this engine in {@link
    073     * org.apache.turbine.services.template.TemplateService}'s
    074     * registry with.
    075     * @return the list of extensions this engine supports
    076     */
    077    String[] getAssociatedFileExtensions();
    078
    079    /**
    080     * Use the specific template engine to determine whether
    081     * a given template exists. This allows Turbine the TemplateService
    082     * to delegate the search for a template to the template
    083     * engine being used for the view. This gives us the
    084     * advantage of fully utilizing the capabilities of
    085     * template engine with respect to retrieving templates
    086     * from arbitrary sources.
    087     *
    088     * @param template The name of the template to check the existence of.
    089     * @return         Whether the specified template exists.
    090     */
    091    boolean templateExists(String template);
    092}