1 files changed, 57 insertions, 38 deletions

diff --git a/container-search/src/main/java/com/yahoo/search/query/Select.java b/container-search/src/main/java/com/yahoo/search/query/Select.java
index ef6a7fe8272..bbc152c6391 100644
--- a/container-search/src/main/java/com/yahoo/search/query/Select.java
+++ b/container-search/src/main/java/com/yahoo/search/query/Select.java
@@ -12,7 +12,9 @@ import com.yahoo.search.yql.VespaGroupingStep;
 
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.LinkedHashSet;
 import java.util.List;
+import java.util.Objects;
 
 
 /**
@@ -30,69 +32,75 @@ public class Select implements Cloneable {
     public static final String WHERE = "where";
     public static final String GROUPING = "grouping";
 
-    private static Model model;
-    private Query parent;
-    private String where = "";
-    private String grouping = "";
-    private List<GroupingRequest> groupingRequests = new ArrayList<>();
+    private final Query parent;
+    private final List<GroupingRequest> groupingRequests;
+
+    private String where;
+    private String grouping;
 
     static {
         argumentType = new QueryProfileType(SELECT);
         argumentType.setStrict(true);
         argumentType.setBuiltin(true);
-        argumentType.addField(new FieldDescription(WHERE, "string", "where"));
-        argumentType.addField(new FieldDescription(GROUPING, "string", "grouping"));
+        argumentType.addField(new FieldDescription(WHERE, "string"));
+        argumentType.addField(new FieldDescription(GROUPING, "string"));
         argumentType.freeze();
-        argumentTypeName=new CompoundName(argumentType.getId().getName());
+        argumentTypeName = new CompoundName(argumentType.getId().getName());
     }
 
     public static QueryProfileType getArgumentType() { return argumentType; }
 
-    public Select(String where, String grouping){
-        this.where = where;
-        this.grouping = grouping;
-    }
-
+    /** Creates an empty select statement */
     public Select(Query query) {
-        setParent(query);
-        model = query.getModel();
+        this("", "", query);
     }
 
+    public Select(String where, String grouping, Query query) {
+        this(where, grouping, query, Collections.emptyList());
+    }
 
-    /** Returns the query owning this, never null */
-    private Query getParent() { return parent; }
-
-
-    /** Assigns the query owning this */
-    public void setParent(Query parent) {
-        if (parent==null) throw new NullPointerException("A query models owner cannot be null");
-        this.parent = parent;
+    private Select(String where, String grouping, Query query, List<GroupingRequest> groupingRequests) {
+        this.where = Objects.requireNonNull(where, "A Select must have a where string (possibly the empty string)");
+        this.grouping = Objects.requireNonNull(grouping, "A Select must have a select string (possibly the empty string)");
+        this.parent = Objects.requireNonNull(query, "A Select must have a parent query");
+        this.groupingRequests = deepCopy(groupingRequests, this);
     }
 
+    private static List<GroupingRequest> deepCopy(List<GroupingRequest> groupingRequests, Select parentOfCopy) {
+        List<GroupingRequest> copy = new ArrayList<>(groupingRequests.size());
+        for (GroupingRequest request : groupingRequests)
+            copy.add(request.copy(parentOfCopy));
+        return copy;
+    }
 
-    /** Set the where-clause for the query. Must be a JSON-string, with the format described in the Select Reference doc:
-     * @see <a href="https://docs.vespa.ai/documentation/reference/select-reference.html">https://docs.vespa.ai/documentation/reference/select-reference.html</a>
+    /**
+     * Sets the document selection criterion of the query.
+     *
+     * @param where the documents to select as a JSON string on the format specified in
+     *        <a href="https://docs.vespa.ai/documentation/reference/select-reference.html">the select reference doc</a>
      */
     public void setWhereString(String where) {
         this.where = where;
-        model.setType(SELECT);
+        parent.getModel().setType(SELECT);
 
-        // Setting the queryTree to null
-        model.setQueryString(null);
+        // This replaces the current query
+        parent.getModel().clearQueryTree();
     }
 
-
-    /** Returns the where-clause in the query */
+    /** Returns the where clause string previously assigned, or an empty string if none */
     public String getWhereString(){ return where; }
 
 
-    /** Set the grouping-string for the query. Must be a JSON-string, with the format described in the Select Reference doc:
-     * @see <a href="https://docs.vespa.ai/documentation/reference/select-reference.html">https://docs.vespa.ai/documentation/reference/select-reference.html</a>
-     * */
-    public void setGroupingString(String grouping){
+    /**
+     * Sets the grouping operation of the query.
+     *
+     * @param grouping the grouping to perform as a JSON string on the format specified in
+     *        <a href="https://docs.vespa.ai/documentation/reference/select-reference.html">the select reference doc</a>
+     */
+    public void setGroupingString(String grouping) {
+        groupingRequests.clear();
         this.grouping = grouping;
         SelectParser parser = (SelectParser) ParserFactory.newInstance(Query.Type.SELECT, new ParserEnvironment());
-
         for (VespaGroupingStep step : parser.getGroupingSteps(grouping)) {
             GroupingRequest.newInstance(parent)
                     .setRootOperation(step.getOperation())
@@ -106,9 +114,11 @@ public class Select implements Cloneable {
         return grouping;
     }
 
-
-    /** Returns the query's {@link GroupingRequest} objects, as mutable list */
-    public List<GroupingRequest> getGrouping(){ return groupingRequests; }
+    /**
+     * Returns the query's {@link GroupingRequest} as a mutable list. Changing this directly changes the grouping
+     * operations which will be performed by this query.
+     */
+    public List<GroupingRequest> getGrouping() { return groupingRequests; }
 
 
     @Override
@@ -116,4 +126,13 @@ public class Select implements Cloneable {
         return "where: [" + where + "], grouping: [" + grouping+ "]";
     }
 
+    @Override
+    public Object clone() {
+        return new Select(where, grouping, parent, groupingRequests);
+    }
+
+    public Select cloneFor(Query parent)  {
+        return new Select(where, grouping, parent, groupingRequests);
+    }
+
 }