Use WeakReferences when in iterate query mode

ebean-test/src/test/java/org/tests/basic/TestPersistenceContext.java

@@ -2,16 +2,23 @@ package org.tests.basic;
 
 import io.ebean.BaseTestCase;
 import io.ebean.DB;
+import io.ebean.Query;
+import io.ebean.Transaction;
+import io.ebeaninternal.api.SpiPersistenceContext;
+import io.ebeaninternal.api.SpiTransaction;
+
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.tests.model.basic.Customer;
 import org.tests.model.basic.Order;
 import org.tests.model.basic.ResetBasicData;
 
+import java.util.List;
 import java.util.WeakHashMap;
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class TestPersistenceContext extends BaseTestCase {
@@ -112,6 +119,65 @@ public class TestPersistenceContext extends BaseTestCase {
         }
       });
     }
+  }
+  
+  @Disabled // run manually
+  @Test
+  void testPcScopes() throws InterruptedException {
 
+    for (int i = 0; i < 5000; i++) {
+      Customer c = new Customer();
+      c.setName("Customer #" + i);
+      DB.save(c);
+      Order o = new Order();
+      o.setCustomer(c);
+      DB.save(o);
+    }
+
+    try (Transaction txn = DB.beginTransaction()) {
+      List<Customer> first100 = DB.find(Customer.class).where().le("id", 100).findList();
+      assertEquals(100, first100.size());
+      for (Customer c : first100) {
+        c.setSmallnote("one of the first 100");
+      }
+
+      Customer[] lastBean = new Customer[1];
+      DB.find(Customer.class).setLazyLoadBatchSize(1).findEach(customer -> {
+        if (customer.getId() <= 100) {
+          assertEquals("one of the first 100", customer.getSmallnote());
+          // nested finds
+          DB.find(Order.class).where().eq("customer", customer).findEach(20, consumer->{});
+        } else {
+          assertNotEquals("one of the first 100", customer.getSmallnote());
+        }
+        lastBean[0] = customer;
+      });
+
+      SpiPersistenceContext pc = ((SpiTransaction) txn).getPersistenceContext();
+      System.out.println(pc.toString()); // Customer=size:5000 (4900 weak), Order=size:100 (100 weak)
+        
+      System.gc();
+      Thread.sleep(100);
+      pc.get(Customer.class, 1); // trigger expungeStaleEntries
+      pc.get(Order.class, 1); // Checkme: Would it be a problem, that every classContext has its own queue
+      System.out.println(pc.toString()); // Customer=size:101 (1 weak), no orders
+
+      first100 = DB.find(Customer.class).where().le("id", 100).findList();
+      for (Customer c : first100) {
+        assertEquals("one of the first 100", c.getSmallnote());
+      }
+      Customer lastBeanFromDb = DB.find(Customer.class).setId(lastBean[0].getId()).findOne();
+      assertTrue(lastBeanFromDb == lastBean[0]);
+      
+      // read 200
+     DB.find(Customer.class).where().le("id", 200).findList();
+      System.out.println(pc.toString()); // Customer=size:201 (1 weak)
+      
+      lastBean[0] = null;
+      lastBeanFromDb = null;
+      System.gc();
+      Thread.sleep(100);
+      System.out.println(pc.toString()); // Customer=size:200 (0 weak)
+    }
   }
 }