org.eclipse.jst.pagedesigner/src/org/eclipse/jst/pagedesigner/preview/PageExpressionContext.java

   1 /*******************************************************************************\r
   2  * Copyright (c) 2006 Sybase, Inc. and others.\r
   3  *\r
   4  * All rights reserved. This program and the accompanying materials\r
   5  * are made available under the terms of the Eclipse Public License v1.0\r
   6  * which accompanies this distribution, and is available at\r
   7  * http://www.eclipse.org/legal/epl-v10.html\r
   8  *\r
   9  * Contributors:\r
  10  *     Sybase, Inc. - initial API and implementation\r
  11  *     Oracle - move to pluggable EL resolving\r
  12  *******************************************************************************/\r
  13 package org.eclipse.jst.pagedesigner.preview;\r
  14 \r
  15 import java.io.BufferedInputStream;\r
  16 import java.io.InputStream;\r
  17 import java.util.ArrayList;\r
  18 import java.util.List;\r
  19 import java.util.Map;\r
  20 import java.util.Properties;\r
  21 \r
  22 import javax.servlet.jsp.el.ELException;\r
  23 \r
  24 import org.eclipse.core.resources.IProject;\r
  25 import org.eclipse.core.resources.IStorage;\r
  26 import org.eclipse.core.runtime.CoreException;\r
  27 import org.eclipse.core.runtime.IConfigurationElement;\r
  28 import org.eclipse.core.runtime.IExtension;\r
  29 import org.eclipse.core.runtime.IExtensionPoint;\r
  30 import org.eclipse.core.runtime.Platform;\r
  31 import org.eclipse.jst.jsf.common.ui.internal.logging.Logger;\r
  32 import org.eclipse.jst.jsf.common.ui.internal.utils.ResourceUtils;\r
  33 import org.eclipse.jst.jsf.core.internal.tld.LoadBundleUtil;\r
  34 import org.eclipse.jst.pagedesigner.IJMTConstants;\r
  35 import org.eclipse.jst.pagedesigner.PDPlugin;\r
  36 import org.eclipse.jst.pagedesigner.jsp.core.pagevar.IPageVariablesProvider;\r
  37 import org.eclipse.jst.pagedesigner.jsp.core.pagevar.IVariableInfo;\r
  38 import org.w3c.dom.Element;\r
  39 \r
  40 /**\r
  41  * This is a static class. But it has "session" concept in it. To make it static\r
  42  * is only to simplify its use.\r
  43  * \r
  44  * @author mengbo, ian.trimble@oracle.com\r
  45  */\r
  46 public class PageExpressionContext {\r
  47         private static final Logger _log = PDPlugin.getLogger(PageExpressionContext.class);\r
  48 \r
  49         static PageExpressionContext _current;\r
  50 \r
  51         List _pageVarProviders = new ArrayList();\r
  52 \r
  53         private IProject _prj;\r
  54 \r
  55         /**\r
  56          * @param prj\r
  57          */\r
  58         public PageExpressionContext(IProject prj) {\r
  59                 _prj = prj;\r
  60         }\r
  61 \r
  62         /**\r
  63          * reset the context.\r
  64          */\r
  65         public static void reset() {\r
  66                 _current = null;\r
  67         }\r
  68 \r
  69         /**\r
  70          * Initialize the current context\r
  71          * @param prj\r
  72          */\r
  73         public static void initialize(IProject prj) {\r
  74                 _current = new PageExpressionContext(prj);\r
  75         }\r
  76 \r
  77         /**\r
  78          * @return the current context\r
  79          */\r
  80         public static PageExpressionContext getCurrent() {\r
  81                 return _current;\r
  82         }\r
  83 \r
  84         /**\r
  85          * @param provider\r
  86          */\r
  87         public void pushPageVarProvider(IPageVariablesProvider provider) {\r
  88                 _pageVarProviders.add(provider);\r
  89         }\r
  90 \r
  91         /**\r
  92          * @param provider\r
  93          */\r
  94         public void popPageVarProvider(IPageVariablesProvider provider) {\r
  95                 try {\r
  96                         _pageVarProviders.remove(_pageVarProviders.size() - 1);\r
  97                 } catch (Exception ex) {\r
  98                         _log.info("PageExpressionContext.Info.0", ex); //$NON-NLS-1$\r
  99                 }\r
 100         }\r
 101 \r
 102         /**\r
 103          * This method is for design time expression evaluation.\r
 104          * \r
 105          * @param expression\r
 106          * @param expectedClass \r
 107          * @param options Current Element is passed with a key of "ELEMENT"\r
 108          * @return the result of evaluating the expression\r
 109          * @throws ELException \r
 110          */\r
 111         public Object evaluateExpression(String expression, Class expectedClass, Map options)\r
 112                         throws ELException {\r
 113                 //Bug 319317 - Third-party plug-in providing javax.servlet.jsp.el version 2.1 or greater breaks WPE preview\r
 114                 String ret = expression;\r
 115                 if (options != null) {\r
 116                         Object objElement = options.get("ELEMENT"); //$NON-NLS-1$\r
 117                         if (objElement instanceof Element) {\r
 118                                 ret = ELValueResolver.resolve((Element)objElement, expression);\r
 119                         }\r
 120                 }\r
 121                 return ret;\r
 122         }\r
 123 \r
 124         /**\r
 125          * Gets an Object associated with a page variable.\r
 126          * @param varName Page variable name.\r
 127          * @return The Object associated with the named page variable, or null if the Object cannot be\r
 128          * located.\r
 129          */\r
 130         public Object getPageVariable(String varName) {\r
 131                 Object ret = null;\r
 132                 // reverse order.\r
 133                 for (int k = _pageVarProviders.size() - 1; k >= 0; k--) {\r
 134                         IPageVariablesProvider _pageVars = (IPageVariablesProvider) _pageVarProviders.get(k);\r
 135                         if (_pageVars != null) {\r
 136                                 IVariableInfo[] vars = _pageVars.getBeanInfos();\r
 137                                 if (vars != null) {\r
 138                                         for (int i = 0; i < vars.length; i++) {\r
 139                                                 if (varName.equals(vars[i].getName())) {\r
 140                                                         if (vars[i].getMode() == IVariableInfo.RESOURCEBUNDLE) {\r
 141                                                                 String resourceName = vars[i].getTypeInfoString();\r
 142                                                                 IStorage storage = null;\r
 143                                                                 try {\r
 144                                                                         storage = LoadBundleUtil.getLoadBundleResource(_prj, resourceName);\r
 145                                                                 } catch (CoreException cex) {\r
 146                                                                         _log.info("PageExpressionContext.Info.0", cex); //$NON-NLS-1$\r
 147                                                                 }\r
 148                                                                 if (storage != null) {\r
 149                                                                         InputStream input = null;\r
 150                                                                         try {\r
 151                                                                                 input = new BufferedInputStream(storage.getContents());\r
 152                                                                                 Properties properties = new Properties();\r
 153                                                                                 properties.load(input);\r
 154                                                                                 ret = properties;\r
 155                                                                         } catch (Exception ignored) {\r
 156                                                                                 //ignore - we'll return null\r
 157                                                                         } finally {\r
 158                                                                                 ResourceUtils.ensureClosed(input);\r
 159                                                                         }\r
 160                                                                 }\r
 161                                                         }\r
 162                                                 }\r
 163                                         }\r
 164                                 }\r
 165                         }\r
 166                 }\r
 167                 return ret;\r
 168         }\r
 169 \r
 170 \r
 171 \r
 172         static class ELValueResolver {\r
 173 \r
 174                 static List<IELValueResolver> elValueResolvers;\r
 175 \r
 176                 public static String resolve(final Element element, final String elExpression) {\r
 177                         String value = elExpression;\r
 178                         if (elValueResolvers == null) {\r
 179                                 readELValueResolvers();\r
 180                         }\r
 181                         for (IELValueResolver elValueResolver: elValueResolvers) {\r
 182                                 value = elValueResolver.resolve(element, value);\r
 183                         }\r
 184                         return value;\r
 185                 }\r
 186 \r
 187                 private static void readELValueResolvers() {\r
 188                         elValueResolvers = new ArrayList<IELValueResolver>();\r
 189                         final IExtensionPoint pdExtPt =\r
 190                                 Platform.getExtensionRegistry().getExtensionPoint(\r
 191                                                 PDPlugin.getPluginId(), IJMTConstants.EXTENSION_POINT_PAGEDESIGNER);\r
 192                         final IExtension[] extensions = pdExtPt.getExtensions();\r
 193                         for (final IExtension extension: extensions) {\r
 194                                 final IConfigurationElement[] configElements = extension.getConfigurationElements();\r
 195                                 for (final IConfigurationElement configElement: configElements) {\r
 196                                         if (configElement.getName().equals("elValueResolver")) { //$NON-NLS-1$\r
 197                                                 try {\r
 198                                                         final Object objValueResolver = configElement.createExecutableExtension("class"); //$NON-NLS-1$\r
 199                                                         if (objValueResolver instanceof IELValueResolver) {\r
 200                                                                 if (configElement.getContributor().getName().startsWith("org.eclipse.jst")) { //$NON-NLS-1$\r
 201                                                                         //add to end (give precedence to contributor-provided resolvers)\r
 202                                                                         elValueResolvers.add((IELValueResolver)objValueResolver);\r
 203                                                                 } else {\r
 204                                                                         //add at beginning (give precedence to contributor-provided resolvers)\r
 205                                                                         elValueResolvers.add(0, (IELValueResolver)objValueResolver);\r
 206                                                                 }\r
 207                                                         }\r
 208                                                 } catch(CoreException ce) {\r
 209                                                         PDPlugin.log("Error reading extensions for: " + configElement.toString(), ce); //$NON-NLS-1$\r
 210                                                 }\r
 211                                         }\r
 212                                 }\r
 213                         }\r
 214                 }\r
 215 \r
 216         }\r
 217 \r
 218 }\r