001 package org.apache.turbine.services.template;
002
003
004 /*
005 * Licensed to the Apache Software Foundation (ASF) under one
006 * or more contributor license agreements. See the NOTICE file
007 * distributed with this work for additional information
008 * regarding copyright ownership. The ASF licenses this file
009 * to you under the Apache License, Version 2.0 (the
010 * "License"); you may not use this file except in compliance
011 * with the License. You may obtain a copy of the License at
012 *
013 * http://www.apache.org/licenses/LICENSE-2.0
014 *
015 * Unless required by applicable law or agreed to in writing,
016 * software distributed under the License is distributed on an
017 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
018 * KIND, either express or implied. See the License for the
019 * specific language governing permissions and limitations
020 * under the License.
021 */
022
023
024 import java.util.Hashtable;
025
026 /**
027 * This is the interface that all template engine services must adhere
028 * to. This includes the Velocity, WebMacro, FreeMarker, and JSP
029 * services.
030 *
031 * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
032 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
033 * @version $Id: TemplateEngineService.java 1078552 2011-03-06 19:58:46Z tv $ */
034 public interface TemplateEngineService
035 {
036 static final String TEMPLATE_EXTENSIONS = "template.extension";
037 static final String DEFAULT_TEMPLATE_EXTENSION = "template.default.extension";
038 static final String DEFAULT_PAGE = "default.page";
039 static final String DEFAULT_SCREEN = "default.screen";
040 static final String DEFAULT_LAYOUT = "default.layout";
041 static final String DEFAULT_NAVIGATION = "default.navigation";
042 static final String DEFAULT_ERROR_SCREEN = "default.error.screen";
043 static final String DEFAULT_LAYOUT_TEMPLATE = "default.layout.template";
044 static final String DEFAULT_SCREEN_TEMPLATE = "default.screen.template";
045 static final String DEFAULT_NAVIGATION_TEMPLATE = "default.navigation.template";
046
047 /**
048 * Return the configuration of the template engine in
049 * the form of a Hashtable.
050 */
051 Hashtable<String, Object> getTemplateEngineServiceConfiguration();
052
053 /**
054 * Initializes file extension associations and registers with the
055 * template service.
056 *
057 * @param defaultExt The default file extension association to use
058 * in case of properties file misconfiguration.
059 */
060 void registerConfiguration(String defaultExt);
061
062 /**
063 * Supplies the file extension to key this engine in {@link
064 * org.apache.turbine.services.template.TemplateService}'s
065 * registry with.
066 */
067 String[] getAssociatedFileExtensions();
068
069 /**
070 * Use the specific template engine to determine whether
071 * a given template exists. This allows Turbine the TemplateService
072 * to delegate the search for a template to the template
073 * engine being used for the view. This gives us the
074 * advantage of fully utilizing the capabilities of
075 * template engine with respect to retrieving templates
076 * from arbitrary sources.
077 *
078 * @param template The name of the template to check the existance of.
079 * @return Whether the specified template exists.
080 */
081 boolean templateExists(String template);
082 }