/*
 *    Copyright 2009-2014 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */

package org.apache.ibatis.scripting.xmltags;

import java.io.StringReader;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import ognl.ExpressionSyntaxException;
import ognl.Node;
import ognl.Ognl;
import ognl.OgnlException;
import ognl.OgnlParser;
import ognl.ParseException;
import ognl.TokenMgrError;

import org.apache.ibatis.builder.BuilderException;

/**
 * Caches OGNL parsed expressions.
 *  
 * @see http://code.google.com/p/mybatis/issues/detail?id=342
 *
 * @author Eduardo Macarron
 */
public class OgnlCache {

  private static final Map<String, ognl.Node> expressionCache = new ConcurrentHashMap<String, ognl.Node>();

  public static Object getValue(String expression, Object root) {
    try {
      Map context = Ognl.createDefaultContext(root, new OgnlClassResolver());
      return Ognl.getValue(parseExpression(expression), context, root);
    } catch (OgnlException e) {
      throw new BuilderException("Error evaluating expression '" + expression + "'. Cause: " + e, e);
    }
  }

  private static Object parseExpression(String expression) throws OgnlException {
    try {
      Node node = expressionCache.get(expression);
      if (node == null) {
        node = new OgnlParser(new StringReader(expression)).topLevelExpression();
        expressionCache.put(expression, node);
      }
      return node;
    } catch (ParseException e) {
      throw new ExpressionSyntaxException(expression, e);
    } catch (TokenMgrError e) {
      throw new ExpressionSyntaxException(expression, e);
    }
  }

}

@@ -693,37 +693,8 @@
 s;%0A%0A
-import java.io.StringReader;%0A
 impo
@@ -775,175 +775,39 @@
 gnl.
-ExpressionSyntaxException;%0Aimport ognl.Node;%0Aimport ognl.Ognl;%0Aimport ognl.OgnlException;%0Aimport ognl.OgnlParser;%0Aimport ognl.ParseException;%0Aimport ognl.TokenMgrError
+Ognl;%0Aimport ognl.OgnlException
 ;%0A%0Ai
@@ -1059,25 +1059,22 @@
 String, 
-ognl.Node
+Object
 %3E expres
@@ -1119,17 +1119,14 @@
 ng, 
-ognl.Node
+Object
 %3E();
@@ -1588,24 +1588,14 @@
     
-try %7B%0A      Node
+Object
  nod
@@ -1635,18 +1635,16 @@
 n);%0A    
-  
 if (node
@@ -1665,71 +1665,37 @@
     
-  
 node =
- new
  Ognl
-P
+.p
 arse
-r(new StringReader(expression)).topLevelE
+Expression(e
 xpre
@@ -1699,17 +1699,16 @@
 pression
-(
 );%0A     
@@ -1708,18 +1708,16 @@
 ;%0A      
-  
 expressi
@@ -1751,22 +1751,18 @@
 e);%0A    
-  %7D%0A  
+%7D%0A
     retu
@@ -1774,195 +1774,8 @@
 de;%0A
-    %7D catch (ParseException e) %7B%0A      throw new ExpressionSyntaxException(expression, e);%0A    %7D catch (TokenMgrError e) %7B%0A      throw new ExpressionSyntaxException(expression, e);%0A    %7D%0A
   %7D%0A

Simplify OGNL code