Fix DataSource serialization

processing/src/main/java/io/druid/query/DataSource.java

@@ -27,7 +27,7 @@ import com.fasterxml.jackson.annotation.JsonTypeInfo;
 @JsonTypeInfo(use = JsonTypeInfo.Id.NAME,
               include = JsonTypeInfo.As.PROPERTY,
               property = "type",
-              defaultImpl = TableDataSource.class)
+              defaultImpl = LegacyDataSource.class)
 @JsonSubTypes({
     @JsonSubTypes.Type(value = TableDataSource.class, name = "table"),
     @JsonSubTypes.Type(value = QueryDataSource.class, name = "query")

processing/src/main/java/io/druid/query/LegacyDataSource.java

@@ -0,0 +1,33 @@
+/*
+ * Druid - a distributed column store.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * This file Copyright (C) 2014 N3TWORK, Inc. and contributed to the Druid project
+ * under the Druid Corporate Contributor License Agreement.
+ */
+package io.druid.query;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class LegacyDataSource extends TableDataSource
+{
+  @JsonCreator
+  public LegacyDataSource(String name)
+  {
+    super(name);
+  }
+}

processing/src/main/java/io/druid/query/TableDataSource.java

@@ -31,7 +31,7 @@ public class TableDataSource implements DataSource
   @JsonCreator
   public TableDataSource(@JsonProperty("name") String name)
   {
-    this.name = name.toLowerCase();
+    this.name = (name == null ? null : name.toLowerCase());
   }
 
   public String getName()
@@ -45,7 +45,7 @@ public class TableDataSource implements DataSource
   public boolean equals(Object o)
   {
     if (this == o) return true;
-    if (o == null || getClass() != o.getClass()) return false;
+    if (!(o instanceof TableDataSource)) return false;
 
     TableDataSource that = (TableDataSource) o;