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.TurbineServices;
026 import org.apache.turbine.util.RunData;
027 import org.apache.velocity.context.Context;
028
029 /**
030 * This is a Facade class for PullService.
031 *
032 * This class provides static methods that call related methods of the
033 * implementation of the PullService used by the System, according to
034 * the settings in TurbineResources.
035 *
036 * @author <a href="mailto:jvanzyl@periapt.com">Jason van Zyl</a>
037 * @author <a href="mailto:dlr@finemaltcoding.com">Daniel Rall</a>
038 * @author <a href="mailto:hps@intermeta.de">Henning P. Schmiedehausen</a>
039 * @author <a href="mailto:peter@courcoux.biz">Peter Courcoux</a>
040 * @version $Id: TurbinePull.java 1078552 2011-03-06 19:58:46Z tv $
041 */
042 public abstract class TurbinePull
043 {
044 /**
045 * Utility method for accessing the service
046 * implementation
047 *
048 * @return a PullService implementation instance
049 */
050 public static PullService getService()
051 {
052 return (PullService) TurbineServices
053 .getInstance().getService(PullService.SERVICE_NAME);
054 }
055
056 /**
057 * Get the context containing global tools that will be
058 * use as part of the Turbine Pull Model.
059 *
060 * @return A Context object which contains the
061 * Global Tool instances.
062 */
063 public static final Context getGlobalContext()
064 {
065 return getService().getGlobalContext();
066 }
067
068 /**
069 * Checks whether this service has been registered. This is
070 * required by the TurbineVelocityService so it can determine
071 * whether to attempt to place the ToolBox in the context.
072 * <p>
073 * So users can use Turbine with templates in the traditional
074 * manner. If the Pull Service is not listed in
075 * <code>TurbineResources.props</code>, or no tools are specified
076 * the TurbineVelocityService will behave in its traditional
077 * manner.
078 */
079 public static final boolean isRegistered()
080 {
081 return TurbineServices.getInstance()
082 .isRegistered(PullService.SERVICE_NAME);
083 }
084
085 /**
086 * Return the absolute path of the resources directory
087 * used by application tools.
088 *
089 * @return A directory path in the file system or null.
090 */
091 public static final String getAbsolutePathToResourcesDirectory()
092 {
093 return getService().getAbsolutePathToResourcesDirectory();
094 }
095
096 /**
097 * Return the resources directory. This is relative
098 * to the webapp context.
099 *
100 * @return A directory path to the resources directory relative to the webapp root or null.
101 */
102 public static final String getResourcesDirectory()
103 {
104 return getService().getResourcesDirectory();
105 }
106
107 /**
108 * Populate the given context with all request, session
109 * and persistent scope tools (it is assumed that the context
110 * already wraps the global context, and thus already contains
111 * the global tools).
112 *
113 * @param context a Velocity Context to populate
114 * @param data a RunData object for request specific data
115 */
116 public static void populateContext(Context context, PipelineData pipelineData)
117 {
118 getService().populateContext(context, pipelineData);
119 }
120
121 /**
122 * Populate the given context with all request, session
123 * and persistent scope tools (it is assumed that the context
124 * already wraps the global context, and thus already contains
125 * the global tools).
126 *
127 * @param context a Velocity Context to populate
128 * @param data a RunData object for request specific data
129 */
130 public static void populateContext(Context context, RunData data)
131 {
132 getService().populateContext(context, data);
133 }
134
135 /**
136 * Release tool instances from the given context to the
137 * object pool
138 *
139 * @param context a Velocity Context to release tools from
140 */
141 public static void releaseTools(Context context)
142 {
143 getService().releaseTools(context);
144 }
145
146 /**
147 * Helper method that allows you to easily get a tool
148 * from a Context. Essentially, it just does the cast
149 * to an Application tool for you.
150 *
151 * @param context a Velocity Context to get tools from
152 * @param name the name of the tool to get
153 * @return ApplicationTool null if no tool could be found
154 */
155 public static ApplicationTool getTool(Context context,
156 String name)
157 {
158 try
159 {
160 return (ApplicationTool) context.get(name);
161 }
162 catch (Exception e)
163 {
164 // ignore
165 }
166 return null;
167 }
168 }