[seam-commits] Seam SVN: r10665 - modules/trunk/el/src/main/java/org/jboss/seam/el.

[seam-commits at lists.jboss.org]

Author: shane.bryzak at jboss.com
Date: 2009-04-27 22:45:45 -0400 (Mon, 27 Apr 2009)
New Revision: 10665

Added:
   modules/trunk/el/src/main/java/org/jboss/seam/el/Interpolator.java
Log:
add Interpolator to el module

Added: modules/trunk/el/src/main/java/org/jboss/seam/el/Interpolator.java
===================================================================
--- modules/trunk/el/src/main/java/org/jboss/seam/el/Interpolator.java	                        (rev 0)
+++ modules/trunk/el/src/main/java/org/jboss/seam/el/Interpolator.java	2009-04-28 02:45:45 UTC (rev 10665)
@@ -0,0 +1,171 @@
+package org.jboss.seam.el;
+
+import java.text.MessageFormat;
+import java.util.Locale;
+import java.util.StringTokenizer;
+
+import javax.context.Dependent;
+import javax.inject.Current;
+
+import org.jboss.webbeans.log.LogProvider;
+import org.jboss.webbeans.log.Logging;
+
+/**
+ * Interpolates EL expressions in Strings
+ * 
+ * @author Gavin King
+ */
+ at Dependent
+public class Interpolator
+{
+   private static final LogProvider log = Logging.getLogProvider(Interpolator.class);
+   
+   @Current Expressions expressions;
+   @Current Locale locale;
+
+   /**
+    * Replace all EL expressions in the form #{...} with their evaluated values.
+    * 
+    * @param string
+    *           a template
+    * @return the interpolated string
+    */
+   public String interpolate(String string, Object... params)
+   {
+      if (params == null)
+      {
+         params = new Object[0];
+      }
+
+      if (params.length > 10)
+      {
+         throw new IllegalArgumentException("more than 10 parameters");
+      }
+
+      if (string.indexOf('#') >= 0 || string.indexOf('{') >= 0)
+      {
+         string = interpolateExpressions(string, params);
+      }
+
+      return string;
+   }
+
+   private String interpolateExpressions(String string, Object... params)
+   {
+      StringTokenizer tokens = new StringTokenizer(string, "#{}", true);
+      StringBuilder builder = new StringBuilder(string.length());
+      try
+      {
+         while (tokens.hasMoreTokens())
+         {
+            String tok = tokens.nextToken();
+
+            if ("#".equals(tok) && tokens.hasMoreTokens())
+            {
+               String nextTok = tokens.nextToken();
+
+               while (nextTok.equals("#") && tokens.hasMoreTokens())
+               {
+                  builder.append(tok);
+                  nextTok = tokens.nextToken();
+               }
+
+               if ("{".equals(nextTok))
+               {
+                  String expression = "#{" + tokens.nextToken() + "}";
+                  try
+                  {
+                     Object value = expressions.createValueExpression(expression).getValue();
+                     if (value != null)
+                        builder.append(value);
+                  } catch (Exception e)
+                  {
+                     log.warn("exception interpolating string: " + string, e);
+                  }
+                  tokens.nextToken(); // the trailing "}"
+
+               } else if (nextTok.equals("#"))
+               {
+                  // could be trailing #
+                  builder.append("#");
+
+               } else
+               {
+                  int index;
+                  try
+                  {
+                     index = Integer.parseInt(nextTok.substring(0, 1));
+                     if (index >= params.length)
+                     {
+                        // log.warn("parameter index out of bounds: " + index +
+                        // " in: " + string);
+                        builder.append("#").append(nextTok);
+                     } else
+                     {
+                        builder.append(params[index]).append(
+                              nextTok.substring(1));
+                     }
+                  } catch (NumberFormatException nfe)
+                  {
+                     builder.append("#").append(nextTok);
+                  }
+               }
+            } else if ("{".equals(tok))
+            {
+               StringBuilder expr = new StringBuilder();
+
+               expr.append(tok);
+               int level = 1;
+
+               while (tokens.hasMoreTokens())
+               {
+                  String nextTok = tokens.nextToken();
+                  expr.append(nextTok);
+
+                  if (nextTok.equals("{"))
+                  {
+                     ++level;
+                  } else if (nextTok.equals("}"))
+                  {
+                     if (--level == 0)
+                     {
+                        try
+                        {
+                           if (params.length == 0)
+                           {
+                              builder.append(expr.toString());
+                           } else
+                           {
+                              String value = new MessageFormat(expr.toString(),
+                                    locale).format(params);
+                              builder.append(value);
+                           }
+                        } catch (Exception e)
+                        {
+                           // if it is a bad message, use the expression itself
+                           builder.append(expr);
+                        }
+                        expr = null;
+                        break;
+                     }
+                  }
+               }
+
+               if (expr != null)
+               {
+                  builder.append(expr);
+               }
+            } else
+            {
+               builder.append(tok);
+            }
+         }
+      } catch (Exception e)
+      {
+         log.warn("exception interpolating string: " + string, e);
+      }
+
+      return builder.toString();
+   }
+
+}