001    package org.apache.turbine.services.pull;
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 org.apache.turbine.pipeline.PipelineData;
025    import org.apache.turbine.services.Service;
026    import org.apache.turbine.util.RunData;
027    import org.apache.velocity.context.Context;
028    
029    /**
030     * The Pull Service manages the creation of application
031     * tools that are available to all templates in a
032     * Turbine application. By using the Pull Service you
033     * can avoid having to make Screens to populate a
034     * context for use in a particular template. The Pull
035     * Service creates a set of tools, as specified in
036     * the TR.props file.
037     *
038     * These tools can have global scope, request scope,
039     * authorized or session scope (i.e. stored in user temp hashmap)
040     * or persistent scope (i.e. stored in user perm hashmap)
041     *
042     * The standard way of referencing these global
043     * tools is through the toolbox handle. This handle
044     * is typically $toolbox, but can be specified in the
045     * TR.props file.
046     *
047     * So, for example, if you had a UI Manager tool
048     * which created a set of UI attributes from a
049     * properties file, and one of the properties
050     * was 'bgcolor', then you could access this
051     * UI attribute with $ui.bgcolor. The identifier
052     * that is given to the tool, in this case 'ui', can
053     * be specified as well.
054     *
055     * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
056     * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
057     * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
058     * @version $Id: PullService.java 957284 2010-06-23 17:53:31Z tv $
059     */
060    public interface PullService
061            extends Service
062    {
063        /** The key under which this service is stored in TurbineServices. */
064        String SERVICE_NAME = "PullService";
065    
066        /** Property Key for the global tools */
067        String GLOBAL_TOOL = "tool.global";
068    
069        /** Property Key for the request tools */
070        String REQUEST_TOOL = "tool.request";
071    
072        /** Property Key for the session tools */
073        String SESSION_TOOL = "tool.session";
074    
075        /** Property Key for the authorized tools */
076        String AUTHORIZED_TOOL = "tool.authorized";
077    
078        /** Property Key for the persistent tools */
079        String PERSISTENT_TOOL = "tool.persistent";
080    
081        /** Property tag for application tool resources directory */
082        String TOOL_RESOURCES_DIR_KEY = "tools.resources.dir";
083    
084        /**
085         * Default value for the application tool resources. This is relative
086         * to the webapp root
087         */
088        String TOOL_RESOURCES_DIR_DEFAULT = "resources";
089    
090        /**
091         * Property tag for per request tool refreshing (for obvious reasons
092         * has no effect for per-request tools)
093         */
094        String TOOLS_PER_REQUEST_REFRESH_KEY = "tools.per.request.refresh";
095    
096        /** Default value for per request tool refreshing */
097        boolean TOOLS_PER_REQUEST_REFRESH_DEFAULT = false;
098    
099        /** prefix for key used in the session to store session scope pull tools */
100        String SESSION_TOOLS_ATTRIBUTE_PREFIX = "turbine.sessiontools.";
101    
102        /**
103         * Get the context containing global tools that will be
104         * use as part of the Turbine Pull Model.
105         *
106         * @return A Context object which contains the
107         *         Global Tool instances.
108         */
109        Context getGlobalContext();
110    
111        /**
112         * Populate the given context with all request, session, authorized
113         * and persistent scope tools (it is assumed that the context
114         * already wraps the global context, and thus already contains
115         * the global tools).
116         *
117         * @param context a Velocity Context to populate
118         * @param data a RunData object for request specific data
119         */
120         void populateContext(Context context, PipelineData pipelineData);
121    
122         /**
123          * Populate the given context with all request, session, authorized
124          * and persistent scope tools (it is assumed that the context
125          * already wraps the global context, and thus already contains
126          * the global tools).
127          *
128          * @param context a Velocity Context to populate
129          * @param data a RunData object for request specific data
130          */
131          void populateContext(Context context, RunData data);
132    
133        /**
134         * Return the absolute path of the resources directory
135         * used by application tools.
136         *
137         * @return A directory path in the file system or null.
138         */
139        String getAbsolutePathToResourcesDirectory();
140    
141        /**
142         * Return the resources directory. This is relative
143         * to the webapp context.
144         *
145         * @return A directory path to the resources directory relative to the webapp root or null.
146         */
147        String getResourcesDirectory();
148    
149        /**
150         * Release tool instances from the given context to the
151         * object pool
152         *
153         * @param context a Velocity Context to release tools from
154         */
155        void releaseTools(Context context);
156    }