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1 /* 2 * Scope: a generic MVC framework. 3 * Copyright (c) 2000-2002, The Scope team 4 * All rights reserved. 5 * 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 14 * Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * Neither the name "Scope" nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 26 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR 27 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 28 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 29 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 30 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 31 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 32 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 33 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 34 * 35 * 36 * $Id: ViewContext.java,v 1.12 2002/09/11 19:15:55 ludovicc Exp $ 37 */ 38 package org.scopemvc.controller.basic; 39 40 41 import java.util.HashMap; 42 import java.util.Map; 43 import org.apache.commons.logging.Log; 44 import org.apache.commons.logging.LogFactory; 45 import org.scopemvc.core.View; 46 import org.scopemvc.util.Debug; 47 48 /*** 49 * <P> 50 * 51 * ViewContext handles show/hide of views, errors and has some concept of the 52 * application's context. eg a Swing implementation would show views inside 53 * JFrames or JDialogs and show errors using JOptionPanes. A servlet 54 * implementation would know about the HTTP response and push views into its 55 * stream. </P> <P> 56 * 57 * There's a place in here to store properties per context. This is used in the 58 * servlet implementation to maintain state over a single request. </P> <P> 59 * 60 * Several static methods are used to set the context for an application either 61 * on a global basis (eg Swing) or per-thread (eg servlet): see {@link 62 * #getViewContext} etc. </P> 63 * 64 * @author <a href="mailto:smeyfroi@users.sourceforge.net">Steve Meyfroidt</a> 65 * @created 05 August 2002 66 * @version $Revision: 1.12 $ $Date: 2002/09/11 19:15:55 $ 67 */ 68 public abstract class ViewContext { 69 70 private static final Log LOG = LogFactory.getLog(ViewContext.class); 71 72 // ----------------------- Global context management 73 74 private static ViewContext globalContext; 75 76 private static ThreadLocal localContext = new ThreadLocal(); 77 78 /*** 79 * The properties associated with the ViewContext 80 */ 81 private Map properties = new HashMap(); 82 83 84 /*** 85 * Return the current ViewContext. First try the per-thread context and if 86 * none, returns the global context. May return null if no context is set. 87 * 88 * @return The viewContext value 89 */ 90 public static ViewContext getViewContext() { 91 92 // Try to find a "per Thread" context 93 ViewContext context = (ViewContext) localContext.get(); 94 if (context != null) { 95 return context; 96 } 97 98 return globalContext; 99 // may be null... 100 } 101 102 103 /*** 104 * Set the global ViewContext. 105 * 106 * @param inContext The new globalContext value 107 */ 108 public static void setGlobalContext(ViewContext inContext) { 109 globalContext = inContext; 110 } 111 112 113 /*** 114 * Set a ViewContext for the current thread. 115 * 116 * @param inContext The new threadContext value 117 */ 118 public static void setThreadContext(ViewContext inContext) { 119 if (inContext == null) { 120 throw new IllegalArgumentException("can't set a null ViewContext for a Thread -- see clearThreadContext()"); 121 } 122 123 localContext.set(inContext); 124 } 125 126 127 /*** 128 * Clear the ViewContext for the current thread. 129 */ 130 public static void clearThreadContext() { 131 localContext.set(null); 132 } 133 134 135 /*** 136 * Fetch an arbitrary object under a known key. 137 * 138 * @param inKey The property key 139 * @return The property value 140 */ 141 public Object getProperty(String inKey) { 142 if (LOG.isDebugEnabled()) { 143 LOG.debug("getProperty: " + inKey); 144 } 145 return properties.get(inKey); 146 } 147 148 149 /*** 150 * Show the view 151 * 152 * @param inView The view to show 153 */ 154 public abstract void showView(View inView); 155 156 157 /*** 158 * Hide the view 159 * 160 * @param inView The view to hide 161 */ 162 public abstract void hideView(View inView); 163 164 165 /*** 166 * Show an error message. 167 * 168 * @param inErrorTitle The title for the error message 169 * @param inErrorMessage The error message 170 */ 171 public abstract void showError(String inErrorTitle, String inErrorMessage); 172 173 174 /*** 175 * Exit the application 176 */ 177 public abstract void exit(); 178 179 180 /*** 181 * Start a progress indicator for long operations. 182 */ 183 public abstract void startProgress(); 184 185 186 /*** 187 * Stop the progress indicator. 188 */ 189 public abstract void stopProgress(); 190 191 192 // --------------------- Properties ---------------------------- 193 194 /*** 195 * Store an arbitrary object under a known key. 196 * 197 * @param inKey The element to be added to the Property attribute 198 * @param inObject The element to be added to the Property attribute 199 */ 200 public void addProperty(String inKey, Object inObject) { 201 if (LOG.isDebugEnabled()) { 202 LOG.debug("addProperty: " + inKey + ", " + inObject); 203 } 204 if (inKey == null) { 205 throw new IllegalArgumentException("Can't use a null key."); 206 } 207 properties.put(inKey, inObject); 208 } 209 210 211 /*** 212 * Fetch and remove an arbitrary object under a known key. 213 * 214 * @param inKey The property key 215 * @return The removed value, or null if the key was not defined 216 */ 217 public Object removeProperty(String inKey) { 218 if (LOG.isDebugEnabled()) { 219 LOG.debug("removeProperty: " + inKey); 220 } 221 return properties.remove(inKey); 222 } 223 224 225 /*** 226 * Clear all properties from this context. 227 */ 228 public void clearProperties() { 229 if (LOG.isDebugEnabled()) { 230 LOG.debug("clearProperties"); 231 } 232 properties.clear(); 233 } 234 }

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