#1331 - ENH: Support Aggregation formula with findSingleAttribute() ... max, min, avg, count and count(distinct ..)

src/main/java/io/ebeaninternal/server/query/SqlTreeProperties.java

@@ -1,7 +1,6 @@
 package io.ebeaninternal.server.query;
 
 import io.ebeaninternal.api.ManyWhereJoins;
-import io.ebeaninternal.server.deploy.BeanProperty;
 
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -21,7 +20,7 @@ public class SqlTreeProperties {
   /**
    * The bean properties in order.
    */
-  private final List<BeanProperty> propsList = new ArrayList<>();
+  private final List<SqlTreeProperty> propsList = new ArrayList<>();
 
   /**
    * Maintain a list of property names to detect embedded bean additions.
@@ -32,6 +31,8 @@ public class SqlTreeProperties {
 
   private boolean aggregation;
 
+  private String aggregationPath;
+
   SqlTreeProperties() {
   }
 
@@ -39,17 +40,17 @@ public class SqlTreeProperties {
     return propNames.contains(propName);
   }
 
-  public void add(BeanProperty[] props) {
+  public void add(SqlTreeProperty[] props) {
     propsList.addAll(Arrays.asList(props));
   }
 
-  public void add(BeanProperty prop) {
+  public void add(SqlTreeProperty prop) {
     propsList.add(prop);
     propNames.add(prop.getName());
   }
 
-  public BeanProperty[] getProps() {
-    return propsList.toArray(new BeanProperty[propsList.size()]);
+  public SqlTreeProperty[] getProps() {
+    return propsList.toArray(new SqlTreeProperty[propsList.size()]);
   }
 
   boolean isPartialObject() {
@@ -77,7 +78,6 @@ public class SqlTreeProperties {
   boolean requireSqlDistinct(ManyWhereJoins manyWhereJoins) {
     String joinProperty = aggregationJoin();
     if (joinProperty != null) {
-      aggregation = true;
       manyWhereJoins.addAggregationJoin(joinProperty);
       return false;
     } else {
@@ -97,12 +97,21 @@ public class SqlTreeProperties {
    */
   private String aggregationJoin() {
     if (!allProperties) {
-      for (BeanProperty beanProperty : propsList) {
+      for (SqlTreeProperty beanProperty : propsList) {
         if (beanProperty.isAggregation()) {
-          return beanProperty.getElPrefix();
+          aggregation = true;
+          aggregationPath = beanProperty.getElPrefix();
+          return aggregationPath;
         }
       }
     }
     return null;
   }
+
+  /**
+   * Return true if a top level aggregation which means the Id property must be excluded.
+   */
+  public boolean isAggregationRoot() {
+    return aggregation && (aggregationPath == null);
+  }
 }