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    1   package org.apache.turbine.services.template;
    2
    3   /*
    4    * Licensed to the Apache Software Foundation (ASF) under one
    5    * or more contributor license agreements.  See the NOTICE file
    6    * distributed with this work for additional information
    7    * regarding copyright ownership.  The ASF licenses this file
    8    * to you under the Apache License, Version 2.0 (the
    9    * "License"); you may not use this file except in compliance
    10   * with the License.  You may obtain a copy of the License at
    11   *
    12   *   http://www.apache.org/licenses/LICENSE-2.0
    13   *
    14   * Unless required by applicable law or agreed to in writing,
    15   * software distributed under the License is distributed on an
    16   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    17   * KIND, either express or implied.  See the License for the
    18   * specific language governing permissions and limitations
    19   * under the License.
    20   */
    21
    22  import java.util.Hashtable;
    23
    24  /**
    25   * This is the interface that all template engine services must adhere
    26   * to. This includes the Velocity, WebMacro, FreeMarker, and JSP
    27   * services.
    28   *
    29   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
    30   * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
    31   * @version $Id: TemplateEngineService.java 1706239 2015-10-01 13:18:35Z tv $ */
    32  public interface TemplateEngineService
    33  {
    34      /** Configuration key */
    35      String TEMPLATE_EXTENSIONS = "template.extension";
    36      /** Configuration key */
    37      String DEFAULT_TEMPLATE_EXTENSION = "template.default.extension";
    38      /** Configuration key */
    39      String DEFAULT_PAGE = "default.page";
    40      /** Configuration key */
    41      String DEFAULT_SCREEN = "default.screen";
    42      /** Configuration key */
    43      String DEFAULT_LAYOUT = "default.layout";
    44      /** Configuration key */
    45      String DEFAULT_NAVIGATION = "default.navigation";
    46      /** Configuration key */
    47      String DEFAULT_ERROR_SCREEN = "default.error.screen";
    48      /** Configuration key */
    49      String DEFAULT_LAYOUT_TEMPLATE = "default.layout.template";
    50      /** Configuration key */
    51      String DEFAULT_SCREEN_TEMPLATE = "default.screen.template";
    52      /** Configuration key */
    53      String DEFAULT_NAVIGATION_TEMPLATE = "default.navigation.template";
    54
    55      /**
    56       * Return the configuration of the template engine in
    57       * the form of a Hashtable.
    58       * @return the template engine service configuration map
    59       */
    60      Hashtable<String, Object> getTemplateEngineServiceConfiguration();
    61
    62      /**
    63       * Initializes file extension associations and registers with the
    64       * template service.
    65       *
    66       * @param defaultExt The default file extension association to use
    67       *                   in case of properties file misconfiguration.
    68       */
    69      void registerConfiguration(String defaultExt);
    70
    71      /**
    72       * Supplies the file extension to key this engine in {@link
    73       * org.apache.turbine.services.template.TemplateService}'s
    74       * registry with.
    75       * @return the list of extensions this engine supports
    76       */
    77      String[] getAssociatedFileExtensions();
    78
    79      /**
    80       * Use the specific template engine to determine whether
    81       * a given template exists. This allows Turbine the TemplateService
    82       * to delegate the search for a template to the template
    83       * engine being used for the view. This gives us the
    84       * advantage of fully utilizing the capabilities of
    85       * template engine with respect to retrieving templates
    86       * from arbitrary sources.
    87       *
    88       * @param template The name of the template to check the existence of.
    89       * @return         Whether the specified template exists.
    90       */
    91      boolean templateExists(String template);
    92  }