#1796 - ENH: add query.fetchCache(path) ... for explicitly building part of graph from L2 cache

src/test/java/org/tests/cache/TestBeanFetchJoinCache.java

@@ -2,6 +2,10 @@ package org.tests.cache;
 
 import io.ebean.BaseTestCase;
 import io.ebean.DB;
+import io.ebean.FetchGroup;
+import io.ebean.cache.ServerCache;
+import io.ebean.cache.ServerCacheStatistics;
+import org.ebeantest.LoggedSqlCollector;
 import org.junit.Test;
 import org.tests.model.basic.Customer;
 import org.tests.model.basic.Order;
@@ -10,36 +14,179 @@ import org.tests.model.basic.ResetBasicData;
 import java.util.List;
 
 import static io.ebean.CacheMode.ON;
+import static org.assertj.core.api.Assertions.assertThat;
 
 public class TestBeanFetchJoinCache extends BaseTestCase {
 
+  private final ServerCache customerBeanCache = server().getServerCacheManager().getBeanCache(Customer.class);
+
   @Test
-  public void test() {
+  public void fetchCache_when_allHits() {
 
-    ResetBasicData.reset();
+    initDataClearCache();
+    loadCustomerBeanCache();
 
-//    DB.find(Customer.class)
-//      .setBeanCacheMode(ON)
-//      .findList();
+    customerBeanCache.getStatistics(true);
 
-
-    DB.find(Customer.class)
-      .where().idIn(1,2,3)
-      //.setBeanCacheMode(ON)
-      .findList();
+    LoggedSqlCollector.start();
 
     List<Order> orders = DB.find(Order.class)
-      .fetchQuery("customer", "name")
+      .fetchCache("customer", "status, name")
       .findList();
 
+    final List<String> sql0 = LoggedSqlCollector.current();
+    assertThat(sql0).hasSize(1);
 
-    orders = DB.find(Order.class)
-      .fetchQuery("customer", "+cache, name")
-      .findList();
+    final ServerCacheStatistics statistics = customerBeanCache.getStatistics(true);
+    assertThat(statistics.getHitCount()).isEqualTo(2);
+
+    assertThat(trimSql(sql0.get(0))).doesNotContain("t1.status");
 
     for (Order order : orders) {
-      order.getCustomer().getName();
+      final Customer customer = order.getCustomer();
+      assertThat(customer.getName()).isNotNull();
+      assertThat(customer.getStatus()).isNotNull();
     }
 
+    assertThat(LoggedSqlCollector.stop()).isEmpty();
+  }
+
+  private void loadCustomerBeanCache() {
+    DB.find(Customer.class)
+      .setBeanCacheMode(ON)
+      .findList();
+  }
+
+  @Test
+  public void fetchCache_when_someHits() {
+
+    initDataClearCache();
+
+    DB.find(Customer.class)
+      .setBeanCacheMode(ON)
+      .where().lt("id", 2)
+      .findList();
+
+    customerBeanCache.getStatistics(true);
+
+    LoggedSqlCollector.start();
+
+    List<Order> orders = DB.find(Order.class)
+      .fetchCache("customer")
+      .findList();
+
+    final List<String> sql0 = LoggedSqlCollector.current();
+    assertThat(sql0).hasSize(2);
+    assertThat(sql0.get(0)).contains(" from o_order ");
+    assertThat(sql0.get(1)).contains(" from o_customer t0 where t0.id ");
+
+    final ServerCacheStatistics statistics = customerBeanCache.getStatistics(true);
+    assertThat(statistics.getHitCount()).isEqualTo(1);
+
+    for (Order order : orders) {
+      final Customer customer = order.getCustomer();
+      assertThat(customer.getName()).isNotNull();
+      assertThat(customer.getStatus()).isNotNull();
+    }
+
+    assertThat(LoggedSqlCollector.stop()).isEmpty();
+  }
+
+  @Test
+  public void fetchCache_when_hitsButBeanCachePartiallyLoaded() {
+
+    initDataClearCache();
+
+    DB.find(Customer.class)
+      .setBeanCacheMode(ON)
+      .select("name") // not included status in bean cache
+      .findList();
+
+    customerBeanCache.getStatistics(true);
+
+    LoggedSqlCollector.start();
+
+    List<Order> orders = DB.find(Order.class)
+      .fetchCache("customer")
+      .findList();
+
+    final List<String> sql0 = LoggedSqlCollector.current();
+    assertThat(sql0).hasSize(1);
+
+    final ServerCacheStatistics statistics = customerBeanCache.getStatistics(true);
+    assertThat(statistics.getHitCount()).isEqualTo(2);
+
+    assertThat(trimSql(sql0.get(0))).doesNotContain("t1.status");
+
+    for (Order order : orders) {
+      final Customer customer = order.getCustomer();
+      assertThat(customer.getName()).isNotNull();
+      assertThat(customer.getStatus()).isNotNull(); // We hit the DB here as previously hit bean cache
+    }
+
+    // assert we didn't hit the L2 bean cache the second time around
+    final ServerCacheStatistics statistics1 = customerBeanCache.getStatistics(true);
+    assertThat(statistics1.getHitCount()).isEqualTo(0);
+
+    // assert we did hit the DB the second time around
+    final List<String> sql1 = LoggedSqlCollector.stop();
+    assertThat(sql1).hasSize(1);
+    assertThat(sql1.get(0)).contains(" from o_customer t0 ");
+  }
+
+  private final FetchGroup<Order> fgBasic = FetchGroup.of(Order.class)
+    .fetchCache("customer")
+    .build();
+
+  @Test
+  public void fetchGroup_fetchCache() {
+
+    initDataClearCache();
+
+    loadCustomerBeanCache();
+    customerBeanCache.getStatistics(true);
+
+    List<Order> orders = DB.find(Order.class)
+      .select(fgBasic)
+      .findList();
+
+    assertThat(orders).isNotEmpty();
+
+    final ServerCacheStatistics statistics1 = customerBeanCache.getStatistics(true);
+    assertThat(statistics1.getHitCount()).isEqualTo(2);
+  }
+
+  private final FetchGroup<Order> fgCachePartial = FetchGroup.of(Order.class)
+    .fetchCache("customer", "name")
+    .build();
+
+
+  @Test
+  public void fetchGroup_fetchCache_partial() {
+
+    initDataClearCache();
+
+    customerBeanCache.getStatistics(true);
+
+    LoggedSqlCollector.start();
+
+    List<Order> orders = DB.find(Order.class)
+      .select(fgCachePartial)
+      .findList();
+
+    assertThat(orders).isNotEmpty();
+
+    final ServerCacheStatistics statistics1 = customerBeanCache.getStatistics(true);
+    assertThat(statistics1.getMissCount()).isEqualTo(2);
+
+    final List<String> sql = LoggedSqlCollector.stop();
+    assertThat(sql).hasSize(2);
+    assertThat(sql.get(0)).contains(" from o_order ");
+    assertThat(sql.get(1)).contains(" from o_customer ");
+  }
+
+  private void initDataClearCache() {
+    ResetBasicData.reset();
+    server().getServerCacheManager().clearAll();
   }
 }