Update BeanAdapter.

Author: gk-brown

kilo-client/src/main/java/org/httprpc/kilo/beans/BeanAdapter.java

@@ -392,7 +392,7 @@ private static class RequiredValueException extends IllegalArgumentException {
 
     private static final String SET_PREFIX = "set";
 
-    private static Map<Class<?>, Map<String, Property>> typeProperties = new ConcurrentHashMap<>();
+    private static final Map<Class<?>, Map<String, Property>> typeProperties = new ConcurrentHashMap<>();
 
     /**
      * Constructs a new bean adapter.

kilo-test/src/main/java/org/httprpc/kilo/test/EmployeeSalary.java

@@ -0,0 +1,40 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.httprpc.kilo.test;
+
+import org.httprpc.kilo.sql.Column;
+import org.httprpc.kilo.sql.ForeignKey;
+import org.httprpc.kilo.sql.PrimaryKey;
+import org.httprpc.kilo.sql.Table;
+
+import java.time.LocalDate;
+
+@Table("salaries")
+public record EmployeeSalary(
+    @Column("emp_no")
+    @PrimaryKey
+    @ForeignKey(Employee.class)
+    Integer employeeNumber,
+
+    @Column("salary")
+    Integer salary,
+
+    @Column("from_date")
+    LocalDate fromDate,
+
+    @Column("to_date")
+    LocalDate toDate
+) {
+}

kilo-test/src/main/java/org/httprpc/kilo/test/EmployeeService.java

@@ -84,4 +84,17 @@ public Iterable<Employee> getEmployeesStream() {
 
         return pipe;
     }
+
+    @RequestMethod("GET")
+    @ResourcePath("average-salary")
+    public Double getAverageSalary() throws SQLException {
+        var queryBuilder = QueryBuilder.select(EmployeeSalary.class);
+
+        try (var statement = queryBuilder.prepare(getConnection());
+            var results = queryBuilder.executeQuery(statement)) {
+            var average = averageOf(mapAll(results, BeanAdapter.toType(EmployeeSalary.class)), EmployeeSalary::salary);
+
+            return Double.isNaN(average) ? null : average;
+        }
+    }
 }