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    1   package org.apache.turbine.services.template;
    2
    3
    4   /*
    5    * Licensed to the Apache Software Foundation (ASF) under one
    6    * or more contributor license agreements.  See the NOTICE file
    7    * distributed with this work for additional information
    8    * regarding copyright ownership.  The ASF licenses this file
    9    * to you under the Apache License, Version 2.0 (the
    10   * "License"); you may not use this file except in compliance
    11   * with the License.  You may obtain a copy of the License at
    12   *
    13   *   http://www.apache.org/licenses/LICENSE-2.0
    14   *
    15   * Unless required by applicable law or agreed to in writing,
    16   * software distributed under the License is distributed on an
    17   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
    18   * KIND, either express or implied.  See the License for the
    19   * specific language governing permissions and limitations
    20   * under the License.
    21   */
    22
    23
    24  import java.util.Hashtable;
    25
    26  /**
    27   * This is the interface that all template engine services must adhere
    28   * to. This includes the Velocity, WebMacro, FreeMarker, and JSP
    29   * services.
    30   *
    31   * @author <a href="mailto:jvanzyl@apache.org">Jason van Zyl</a>
    32   * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
    33   * @version $Id: TemplateEngineService.java 1078552 2011-03-06 19:58:46Z tv $ */
    34  public interface TemplateEngineService
    35  {
    36      static final String TEMPLATE_EXTENSIONS = "template.extension";
    37      static final String DEFAULT_TEMPLATE_EXTENSION = "template.default.extension";
    38      static final String DEFAULT_PAGE = "default.page";
    39      static final String DEFAULT_SCREEN = "default.screen";
    40      static final String DEFAULT_LAYOUT = "default.layout";
    41      static final String DEFAULT_NAVIGATION = "default.navigation";
    42      static final String DEFAULT_ERROR_SCREEN = "default.error.screen";
    43      static final String DEFAULT_LAYOUT_TEMPLATE = "default.layout.template";
    44      static final String DEFAULT_SCREEN_TEMPLATE = "default.screen.template";
    45      static final String DEFAULT_NAVIGATION_TEMPLATE = "default.navigation.template";
    46
    47      /**
    48       * Return the configuration of the template engine in
    49       * the form of a Hashtable.
    50       */
    51      Hashtable<String, Object> getTemplateEngineServiceConfiguration();
    52
    53      /**
    54       * Initializes file extension associations and registers with the
    55       * template service.
    56       *
    57       * @param defaultExt The default file extension association to use
    58       *                   in case of properties file misconfiguration.
    59       */
    60      void registerConfiguration(String defaultExt);
    61
    62      /**
    63       * Supplies the file extension to key this engine in {@link
    64       * org.apache.turbine.services.template.TemplateService}'s
    65       * registry with.
    66       */
    67      String[] getAssociatedFileExtensions();
    68
    69      /**
    70       * Use the specific template engine to determine whether
    71       * a given template exists. This allows Turbine the TemplateService
    72       * to delegate the search for a template to the template
    73       * engine being used for the view. This gives us the
    74       * advantage of fully utilizing the capabilities of
    75       * template engine with respect to retrieving templates
    76       * from arbitrary sources.
    77       *
    78       * @param template The name of the template to check the existance of.
    79       * @return         Whether the specified template exists.
    80       */
    81      boolean templateExists(String template);
    82  }