1   package freemarker.ext.jsp;
    2   
    3   import java.lang.reflect.InvocationTargetException;
    4   import java.lang.reflect.Method;
    5   
    6   import javax.servlet.jsp.PageContext;
    7   
    8   import freemarker.core.Environment;
    9   import freemarker.template.TemplateModel;
   10   import freemarker.template.TemplateModelException;
   11   import freemarker.template.utility.UndeclaredThrowableException;
   12   
   13   /**
   14    * @author Attila Szegedi
   15    * @version $Id: PageContextFactory.java,v 1.2 2005/06/11 21:21:09 szegedia Exp $
   16    */
   17   class PageContextFactory {
   18   
   19       private static final Method constructor;
   20       
   21       static {
   22           Class impl;
   23           try {
   24               try {
   25                   PageContext.class.getMethod("getELContext", (Class[]) null);
   26                   impl = Class.forName("freemarker.ext.jsp.FreeMarkerPageContext21");
   27               }
   28               catch(NoSuchMethodException e1) {
   29                   try {
   30                       PageContext.class.getMethod("getExpressionEvaluator", (Class[]) null);
   31                       impl = Class.forName("freemarker.ext.jsp.FreeMarkerPageContext2");
   32                   }
   33                   catch(NoSuchMethodException e2) {
   34                       impl = Class.forName("freemarker.ext.jsp.FreeMarkerPageContext1");
   35                   }
   36               }
   37               constructor = impl.getDeclaredMethod("create", (Class[]) null);
   38           }
   39           catch(ClassNotFoundException e) {
   40               throw new NoClassDefFoundError(e.getMessage());
   41           }
   42           catch(NoSuchMethodException e) {
   43               throw new NoSuchMethodError(e.getMessage());
   44           }
   45       }
   46   
   47       static FreeMarkerPageContext getCurrentPageContext() throws TemplateModelException {
   48           Environment env = Environment.getCurrentEnvironment();
   49           TemplateModel pageContextModel = env.getGlobalVariable(PageContext.PAGECONTEXT);
   50           if(pageContextModel instanceof FreeMarkerPageContext) {
   51               return (FreeMarkerPageContext)pageContextModel;
   52           }
   53           try {
   54               FreeMarkerPageContext pageContext = 
   55                   (FreeMarkerPageContext)constructor.invoke(null, null);
   56               env.setGlobalVariable(PageContext.PAGECONTEXT, pageContext);
   57               return pageContext;
   58           }
   59           catch(IllegalAccessException e) {
   60               throw new IllegalAccessError(e.getMessage());
   61           }
   62           catch(InvocationTargetException e) {
   63               if(e.getTargetException() instanceof TemplateModelException) {
   64                   throw (TemplateModelException)e.getTargetException();
   65               }
   66               throw new UndeclaredThrowableException(e);
   67           }
   68       }
   69       
   70   }