make Context generic so we don't have to cast

core/src/main/java/org/elasticsearch/search/fetch/FetchSubPhase.java

@@ -121,7 +121,7 @@ public interface FetchSubPhase {
      * Fetch phases that use the plugin mechanism must provide a ContextFactory to the SearchContext that creates the fetch phase context and also associates them with a name.
      * See {@link SearchContext#getFetchSubPhaseContext(FetchSubPhase.ContextFactory)}
      */
-    public interface ContextFactory {
+    public interface ContextFactory<SubPhaseContext extends FetchSubPhaseContext> {
 
         /**
          * The name of the context.
@@ -131,6 +131,6 @@ public interface FetchSubPhase {
         /**
          * Creates a new instance of a FetchSubPhaseContext that holds all information a FetchSubPhase needs to execute on hits.
          */
-        public FetchSubPhaseContext newContextInstance();
+        public SubPhaseContext newContextInstance();
     }
 }

core/src/main/java/org/elasticsearch/search/fetch/FetchSubPhaseParseElement.java

@@ -26,11 +26,11 @@ import org.elasticsearch.search.internal.SearchContext;
 /**
  * A parse element for a {@link org.elasticsearch.search.fetch.FetchSubPhase} that is used when parsing a search request.
  */
-public abstract class FetchSubPhaseParseElement implements SearchParseElement {
+public abstract class FetchSubPhaseParseElement<SubPhaseContext extends FetchSubPhaseContext> implements SearchParseElement {
 
     @Override
     final public void parse(XContentParser parser, SearchContext context) throws Exception {
-        FetchSubPhaseContext fetchSubPhaseContext = context.getFetchSubPhaseContext(getContextFactory());
+        SubPhaseContext fetchSubPhaseContext = context.getFetchSubPhaseContext(getContextFactory());
         // this is to make sure that the SubFetchPhase knows it should execute
         fetchSubPhaseContext.setHitExecutionNeeded(true);
         innerParse(parser, fetchSubPhaseContext);
@@ -39,10 +39,10 @@ public abstract class FetchSubPhaseParseElement implements SearchParseElement {
     /**
      * Implement the actual parsing here.
      */
-    protected abstract void innerParse(XContentParser parser, FetchSubPhaseContext fetchSubPhaseContext) throws Exception;
+    protected abstract void innerParse(XContentParser parser, SubPhaseContext fetchSubPhaseContext) throws Exception;
 
     /**
      * Return the ContextFactory for this FetchSubPhase.
      */
-    protected abstract FetchSubPhase.ContextFactory getContextFactory();
+    protected abstract FetchSubPhase.ContextFactory<SubPhaseContext> getContextFactory();
 }

core/src/main/java/org/elasticsearch/search/fetch/fielddata/FieldDataFieldsParseElement.java

@@ -36,11 +36,10 @@ import org.elasticsearch.search.internal.SearchContext;
  * }
  * </pre>
  */
-public class FieldDataFieldsParseElement extends FetchSubPhaseParseElement {
+public class FieldDataFieldsParseElement extends FetchSubPhaseParseElement<FieldDataFieldsContext> {
 
     @Override
-    protected void innerParse(XContentParser parser, FetchSubPhaseContext fetchSubPhaseContext) throws Exception {
+    protected void innerParse(XContentParser parser, FieldDataFieldsContext fieldDataFieldsContext) throws Exception {
-        FieldDataFieldsContext fieldDataFieldsContext = (FieldDataFieldsContext) fetchSubPhaseContext;
         XContentParser.Token token = parser.currentToken();
         if (token == XContentParser.Token.START_ARRAY) {
             while (parser.nextToken() != XContentParser.Token.END_ARRAY) {

core/src/main/java/org/elasticsearch/search/internal/SearchContext.java

@@ -164,7 +164,7 @@ public abstract class SearchContext implements Releasable, HasContextAndHeaders
 
     public abstract SearchContext aggregations(SearchContextAggregations aggregations);
 
-    public abstract FetchSubPhaseContext getFetchSubPhaseContext(FetchSubPhase.ContextFactory contextFactory);
+    public abstract  <SubPhaseContext extends FetchSubPhaseContext> SubPhaseContext getFetchSubPhaseContext(FetchSubPhase.ContextFactory<SubPhaseContext> contextFactory);
 
     public abstract SearchContextHighlight highlight();
 

core/src/test/java/org/elasticsearch/search/fetch/FetchSubPhasePluginTests.java

@@ -183,12 +183,11 @@ public class FetchSubPhasePluginTests extends ElasticsearchIntegrationTest {
         }
     }
 
-    public static class TermVectorsFetchParseElement extends FetchSubPhaseParseElement {
+    public static class TermVectorsFetchParseElement extends FetchSubPhaseParseElement<TermVectorsFetchContext> {
 
         @Override
-        protected void innerParse(XContentParser parser, FetchSubPhaseContext fetchSubPhaseContext) throws Exception {
+        protected void innerParse(XContentParser parser, TermVectorsFetchContext termVectorsFetchContext) throws Exception {
             XContentParser.Token token = parser.currentToken();
-            TermVectorsFetchContext termVectorsFetchContext = (TermVectorsFetchContext) fetchSubPhaseContext;
             if (token == XContentParser.Token.VALUE_STRING) {
                 String fieldName = parser.text();
                 termVectorsFetchContext.setField(fieldName);