OPENJPA-75: Error message for missing identification variable shows nearest Levensthien choice and all avaialble choices

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@681807 13f79535-47bb-0310-9956-ffa450edef68

openjpa-kernel/src/main/java/org/apache/openjpa/kernel/exps/AbstractExpressionBuilder.java

@@ -18,6 +18,7 @@
  */
 package org.apache.openjpa.kernel.exps;
 
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -27,6 +28,7 @@ import java.util.Set;
 
 import org.apache.openjpa.kernel.Filters;
 import org.apache.openjpa.lib.util.Localizer;
+import org.apache.openjpa.lib.util.StringDistance;
 import org.apache.openjpa.lib.util.Localizer.Message;
 import org.apache.openjpa.meta.ClassMetaData;
 import org.apache.openjpa.meta.FieldMetaData;
@@ -280,9 +282,14 @@ public abstract class AbstractExpressionBuilder {
         FieldMetaData fmd = meta.getField(field);
         if (fmd == null) {
             Object val = traverseStaticField(meta.getDescribedType(), field);
-            if (val == null)
+            if (val == null) {
+            	String[] all = meta.getFieldNames();
+            	Class cls = meta.getDescribedType();
                 throw parseException(EX_USER, "no-field",
-                    new Object[]{ meta.getDescribedType(), field }, null);
+                    new Object[] {field, cls.getSimpleName(), 
+                	StringDistance.getClosestLevenshteinDistance(field, all), 
+                	cls.getName(), Arrays.toString(all)}, null);
+            }
 
             return factory.newLiteral(val, Literal.TYPE_UNKNOWN);
         }

openjpa-kernel/src/main/java/org/apache/openjpa/meta/ClassMetaData.java

@@ -26,6 +26,7 @@ import java.security.AccessController;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Comparator;
 import java.util.HashMap;
 import java.util.HashSet;
@@ -2375,4 +2376,29 @@ public class ClassMetaData
     		_cacheTimeout = Integer.MIN_VALUE;
     	}
     }
+    
+    /**
+     * Utility method to get names of all fields including the superclasses'
+     * sorted in lexical order.
+     */
+    public String[] getFieldNames() {
+    	return toNames(getFields());
+    }
+    
+    /**
+     * Utility method to get names of all declared fields excluding the 
+     * superclasses' sorted in lexical order.
+     */
+    public String[] getDeclaredFieldNames() {
+    	return toNames(getDeclaredFields());
+    }
+    
+    String[] toNames(FieldMetaData[] fields) {
+    	List<String> result = new ArrayList<String>();
+    	for (FieldMetaData fmd : fields) {
+    		result.add(fmd.getName());
+    	}
+    	Collections.sort(result);
+    	return result.toArray(new String[result.size()]);
+    }
 }

openjpa-kernel/src/main/resources/org/apache/openjpa/kernel/jpql/localizer.properties

@@ -28,9 +28,10 @@ no-alias: The alias "{0}" was not declared in the statement (declared \
 cant-resolve-type: The entity "{0}" cannot be resolved; please ensure that \
 	the entity name has been declared for the class.
 not-identifer: The specified node ("{0}") is not a valid identifier.
-no-field: No field named "{1}" in class "{0}".
+no-field: No field named "{0}" in "{1}". Did you mean "{2}"? Expected one of \
+	the available field names in "{3}": "{4}".
 unaccessible-field: The field named "{1}" in class "{0}" could not be accessed.
-multi-children: Expression "{0}" does not allow mutliple children ("{1}").
+multi-children: Expression "{0}" does not allow multiple children ("{1}").
 no-children: Expression "{0}" requires at least one child.
 unknown-comp: Unknown comparison operator "{0}".
 wrong-child-count: Wrong number of arguments to expression \