Improve error messages when processing metadata / JPQL queries.

git-svn-id: https://svn.apache.org/repos/asf/openjpa/trunk@572492 13f79535-47bb-0310-9956-ffa450edef68

openjpa-kernel/src/main/java/org/apache/openjpa/kernel/jpql/JPQLExpressionBuilder.java

@@ -164,11 +164,17 @@ public class JPQLExpressionBuilder
         if (c != null)
             cmd = repos.getMetaData(c, loader, assertValid);
         else if (assertValid)
-            cmd = repos.getMetaData(alias, loader, true);
+            cmd = repos.getMetaData(alias, loader, false);
 
-        if (cmd == null && assertValid)
+        if (cmd == null && assertValid) {
-            throw parseException(EX_USER, "not-schema-name",
+            String close = repos.getClosestAliasName(alias);
-                new Object[]{ alias }, null);
+            if (close != null)
+                throw parseException(EX_USER, "not-schema-name-hint",
+                    new Object[]{ alias, close, repos.getAliasNames() }, null);
+            else
+                throw parseException(EX_USER, "not-schema-name",
+                    new Object[]{ alias, repos.getAliasNames() }, null);
+        }
 
         return cmd;
     }

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

@@ -47,6 +47,7 @@ import org.apache.openjpa.lib.log.Log;
 import org.apache.openjpa.lib.util.Closeable;
 import org.apache.openjpa.lib.util.J2DoPrivHelper;
 import org.apache.openjpa.lib.util.Localizer;
+import org.apache.openjpa.lib.util.StringDistance;
 import org.apache.openjpa.util.ImplHelper;
 import org.apache.openjpa.util.InternalException;
 import org.apache.openjpa.util.MetaDataException;
@@ -360,8 +361,7 @@ public class MetaDataRepository
         // maybe this is some type we've seen but just isn't valid
         if (_aliases.containsKey(alias)) {
             if (mustExist)
-                throw new MetaDataException(_loc.get("no-alias-meta", alias,
+                throwNoRegisteredAlias(alias);
-                    _aliases.toString()));
             return null;
         }
 
@@ -370,7 +370,43 @@ public class MetaDataRepository
 
         if (!mustExist)
             return null;
-        throw new MetaDataException(_loc.get("no-alias-meta", alias, _aliases));
+        return throwNoRegisteredAlias(alias);
+    }
+
+    private ClassMetaData throwNoRegisteredAlias(String alias) {
+        String close = getClosestAliasName(alias);
+        if (close != null)
+            throw new MetaDataException(
+                _loc.get("no-alias-meta-hint", alias, _aliases, close));
+        else
+            throw new MetaDataException(
+                _loc.get("no-alias-meta", alias, _aliases));
+    }
+
+    /**
+     * @return the nearest match to the specified alias name
+     * @since 1.1.0
+     */
+    public String getClosestAliasName(String alias) {
+        Collection aliases = getAliasNames();
+        return StringDistance.getClosestLevenshteinDistance(alias, aliases);
+    }
+
+    /**
+     * @return the registered alias names
+     * @since 1.1.0
+     */
+    public Collection getAliasNames() {
+        Collection aliases = new HashSet();
+        synchronized (_aliases) {
+            for (Iterator iter = _aliases.entrySet().iterator();
+                iter.hasNext(); ) {
+                Map.Entry e = (Map.Entry) iter.next();
+                if (e.getValue() != null)
+                    aliases.add(e.getKey());
+            }
+        }
+        return aliases;
     }
 
     /**

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

@@ -36,7 +36,10 @@ unknown-comp: Unknown comparison operator "{0}".
 wrong-child-count: Wrong number of arguments to expression \
 	of type "{1}": should have been {0}, but the following arguments \
 	were specified: "{2}".
-not-schema-name: The name "{0}" is not a recognized entity or identifier.
+not-schema-name: The name "{0}" is not a recognized entity or identifier. \
+    Known entity names: {1}
+not-schema-name-hint: The name "{0}" is not a recognized entity or identifier. \
+    Perhaps you meant {1}, which is a close match. Known entity names: {2}
 duplicate-alias: Alias "{0}" was declared twice.
 unknown-type: Cannot determine the type of field "{0}".
 unexpected-var: The variable "{0}" was found where a constant or \

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

@@ -142,9 +142,15 @@ no-meta: No metadata was found for type "{0}".  Ensure that the class is \
 	if you list your persistent classes, the class is included in your list.
 no-oid-meta: Could not locate metadata for the class using oid "{0}" of \
 	type "{1}".  Registered oid type mappings: "{2}"
-no-alias-meta: Could not locate metadata for the class using alias "{0}". This \
+no-alias-meta: Could not locate metadata for the class using alias "{0}". \
-	could mean that the OpenJPA enhancer or load-time weaver was not run on \
+	This could mean that you have mis-spelled the alias, or that OpenJPA failed\
-    the type whose alias is "{0}". Registered alias mappings: "{1}"
+    to properly load the metadata for the type whose alias is "{0}". \
+    Registered alias mappings: "{1}"
+no-alias-meta-hint: Could not locate metadata for the class using alias "{0}". \
+    Perhaps you meant {2}, which is a close match. \
+	This could mean that you have mis-spelled the alias, or that OpenJPA failed\
+    to properly load the metadata for the type whose alias is "{0}". \
+    Registered alias mappings: "{1}"
 error-registered: An error occurred while processing registered class "{0}".
 failed-registered: A potentially serious error occurred while processing \
 	registered class "{0}".  Deferring processing of this class until next \

openjpa-persistence-jdbc/src/test/java/org/apache/openjpa/persistence/xml/TestSimpleXmlEntity.java

@@ -53,7 +53,8 @@ public class TestSimpleXmlEntity
             fail("should not be able to execute query using short class name " +
                 "for entity that has an entity name specified");
         } catch (ArgumentException ae) {
-            // expected
+            assertTrue(
+                ae.getMessage().indexOf("Perhaps you meant SimpleXml,") != -1);
         }
     }
 
@@ -67,7 +68,8 @@ public class TestSimpleXmlEntity
             fail("should not be able to execute query using short class name " +
                 "for entity that has an entity name specified");
         } catch (ArgumentException ae) {
-            // expected
+            assertTrue(
+                ae.getMessage().indexOf("Perhaps you meant SimpleXml,") != -1);
         }
     }
 }