svn commit: r743567 - /incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java

[awiner]

Author: awiner
Date: Wed Feb 11 23:38:44 2009
New Revision: 743567

URL: http://svn.apache.org/viewvc?rev=743567&view=rev
Log:
Work around JUEL bug where VariableMapper was always null on ELContext

Modified:
    
incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java

Modified: 
incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java
URL: 
http://svn.apache.org/viewvc/incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java?rev=743567&r1=743566&r2=743567&view=diff
==============================================================================
--- 
incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java
 (original)
+++ 
incubator/shindig/trunk/java/common/src/main/java/org/apache/shindig/expressions/Expressions.java
 Wed Feb 11 23:38:44 2009
@@ -20,6 +20,7 @@
 
 import org.json.JSONArray;
 
+import java.util.Map;
 import java.util.Properties;
 import java.util.StringTokenizer;
 
@@ -29,11 +30,14 @@
 import javax.el.ELException;
 import javax.el.ELResolver;
 import javax.el.ExpressionFactory;
+import javax.el.FunctionMapper;
 import javax.el.ListELResolver;
 import javax.el.MapELResolver;
 import javax.el.PropertyNotWritableException;
 import javax.el.ValueExpression;
+import javax.el.VariableMapper;
 
+import com.google.common.collect.Maps;
 import com.google.inject.Inject;
 import com.google.inject.Singleton;
 
@@ -64,7 +68,7 @@
   public Expressions() {
     factory = newExpressionFactory();
     // Stub context with no FunctionMapper, used only to parse expressions
-    parseContext = new SimpleContext();
+    parseContext = new Context(null);
     defaultELResolver = createDefaultELResolver();
   }
 
@@ -79,7 +83,7 @@
     }
 
     composite.add(defaultELResolver);
-    return new SimpleContext(composite);
+    return new Context(composite);
   }
 
   /**
@@ -98,6 +102,10 @@
     return factory.createValueExpression(parseContext, expression, type);
   }
   
+  public ValueExpression constant(Object value, Class<?> type) {
+    return factory.createValueExpression(value, type);
+  }
+  
   private ExpressionFactory newExpressionFactory() {
     Properties properties = new Properties();
     // TODO: configure cache size?
@@ -122,6 +130,54 @@
     return resolver;
   }
 
+  /**
+   * ELContext implementation.  SimpleContext from JUEL would be
+   * sufficient if not for:
+   * 
https://sourceforge.net/tracker2/?func=detail&aid=2590830&group_id=165179&atid=834616
+   */
+  static private class Context extends ELContext {
+    private final ELResolver resolver;
+    private VariableMapper variables;
+
+    public Context(ELResolver resolver) {
+      this.resolver = resolver;
+    }
+    
+    @Override
+    public ELResolver getELResolver() {
+      return resolver;
+    }
+
+    @Override
+    public FunctionMapper getFunctionMapper() {
+      return null;
+    }
+
+    @Override
+    public VariableMapper getVariableMapper() {
+      if (variables == null) {
+        variables = new Variables();
+      }
+      
+      return variables;
+    }
+    
+  }
+  
+  static private class Variables extends VariableMapper {
+    private final Map<String, ValueExpression> variables = Maps.newHashMap();
+    @Override
+    public ValueExpression resolveVariable(String var) {
+      return variables.get(var);
+    }
+
+    @Override
+    public ValueExpression setVariable(String var, ValueExpression expression) 
{
+      return variables.put(var, expression);
+    }
+    
+  }
+  
   /** 
    * Class providing custom type coercion for getValue() where needed.
    * This will be obsolete with JUEL 2.1.1.