Sharing ExpressionEvaluator instances

src/main/java/org/apache/ibatis/scripting/xmltags/ExpressionEvaluator.java

@@ -28,6 +28,8 @@
  */
 public class ExpressionEvaluator {
 
+  public static final ExpressionEvaluator INSTANCE = new ExpressionEvaluator();
+
   public boolean evaluateBoolean(String expression, Object parameterObject) {
     Object value = OgnlCache.getValue(expression, parameterObject);
     if (value instanceof Boolean) {

src/main/java/org/apache/ibatis/scripting/xmltags/ForEachSqlNode.java

@@ -27,7 +27,7 @@
 public class ForEachSqlNode implements SqlNode {
   public static final String ITEM_PREFIX = "__frch_";
 
-  private final ExpressionEvaluator evaluator;
+  private final ExpressionEvaluator evaluator = ExpressionEvaluator.INSTANCE;
   private final String collectionExpression;
   private final Boolean nullable;
   private final SqlNode contents;
@@ -53,7 +53,6 @@ public ForEachSqlNode(Configuration configuration, SqlNode contents, String coll
    */
   public ForEachSqlNode(Configuration configuration, SqlNode contents, String collectionExpression, Boolean nullable,
       String index, String item, String open, String close, String separator) {
-    this.evaluator = new ExpressionEvaluator();
     this.collectionExpression = collectionExpression;
     this.nullable = nullable;
     this.contents = contents;

src/main/java/org/apache/ibatis/scripting/xmltags/IfSqlNode.java

@@ -19,14 +19,13 @@
  * @author Clinton Begin
  */
 public class IfSqlNode implements SqlNode {
-  private final ExpressionEvaluator evaluator;
+  private final ExpressionEvaluator evaluator = ExpressionEvaluator.INSTANCE;
   private final String test;
   private final SqlNode contents;
 
   public IfSqlNode(SqlNode contents, String test) {
     this.test = test;
     this.contents = contents;
-    this.evaluator = new ExpressionEvaluator();
   }
 
   @Override