title: Query a collection property with JDO in Google App Engine
body: <p>I have two classes PaymentJDO and PaymentItemJDO. A payment can have several items. Any payment item is associated with an invoice. 
  I want to retrieve every payment which is related to a particular invoice. I have the invoice Id to query. </p>
  
  <pre><code>@PersistenceCapable(identityType = IdentityType.APPLICATION)
  public class PaymentJDO implements BaseOwnedObject, BasicBean {
      @PrimaryKey
      @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
      protected Long id;
  
      @Persistent
      private Date date;
  
      @Persistent
      private String customerId;
  
      @Persistent
      private String pelicamoId = null;
  
      @Persistent
      @Element(dependent = "true")
      private List&lt;PaymentItemJDO&gt; items;
  
      public void setId(Long id) { this.id = id;}
  
      public String getId() {
          if( id == null ) return null;
          return id.toString();
      }
      public void setId(String id) {
          if(id!=null) {
              this.id = Long.parseLong(id);
          }   
      }
  
      public Date getDate() { return date;}
      public void setDate(Date date) { this.date = date;}
  
      public String getCustomerId() { return customerId;}
      public void setCustomerId(String customerId) { this.customerId = customerId;}
  
      public List&lt;PaymentItemJDO&gt; getItems() { return items;}
      public void setItems(List&lt;PaymentItemJDO&gt; items) {this.items = items;}
  
  
      public String getPelicamoId() { return pelicamoId;}
      public void setPelicamoId(String pelicamoId) { this.pelicamoId = pelicamoId;}
  }
  
  
  @PersistenceCapable(identityType = IdentityType.APPLICATION, detachable="true")
  public class PaymentItemJDO {   
      @PrimaryKey
      @Persistent(valueStrategy = IdGeneratorStrategy.IDENTITY)
      protected Key id;
  
      @Persistent
      private String invoiceId;
  
      @Persistent
      private double amount;
  
      public PaymentItemJDO(String invoiceId) {
          setInvoiceId(invoiceId);
      }
  
      //override equals method for List .contains
      @Override
      public boolean equals(Object item) {
          return ((PaymentItemJDO)item).getInvoiceId().equals(this.invoiceId);
      } 
  
      public Key getId() { return id;}
  
      public String getInvoiceId() { return invoiceId;}
      public void setInvoiceId(String invoiceId) { this.invoiceId = invoiceId;}
  
      public double getAmount() { return amount;}
      public void setAmount(double amount) { this.amount = amount;}
  }
  </code></pre>
  
  <p>I have the next function to query the payments related to a particular invoice</p>
  
  <pre><code>public List&lt;PaymentJDO&gt; getJDOPayments(String invoiceId)  throws SessionExpiredException {
      PersistenceManager pm = JdoUtil.getPm();        
      Query query = pm.newQuery(PaymentJDO.class);
      String pelicamoId = getCurrentPelicamoId();
      query.setFilter("items.contains(:invoice)");
      return (List&lt;PaymentJDO&gt;) query.execute(new PaymentItemJDO(invoiceId));
  }
  </code></pre>
  
  <p>I get the next error</p>
  
  <pre><code>javax.jdo.JDOFatalUserException: Illegal argument
      at org.datanucleus.jdo.NucleusJDOHelper.getJDOExceptionForNucleusException(NucleusJDOHelper.java:344)
      at org.datanucleus.jdo.JDOQuery.execute(JDOQuery.java:252)
      at com.softamo.pelicamo.server.MainServiceImpl.getJDOPayments(MainServiceImpl.java:947)
      at com.softamo.pelicamo.server.MainServiceImpl.getIncomeSummaries(MainServiceImpl.java:817)
      at com.softamo.pelicamo.server.IncomeServiceTest.testGetIncomeSummaries(IncomeServiceTest.java:62)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
      at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
      at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
      at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
      at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
      at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
      at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
      at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
      at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
      at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
      at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
      at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
  NestedThrowablesStackTrace:
  java.lang.IllegalArgumentException: items: com.softamo.pelicamo.server.jdo.PaymentItemJDO is not a supported property type.
      at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedSingleValue(DataTypeUtils.java:184)
      at com.google.appengine.api.datastore.DataTypeUtils.checkSupportedValue(DataTypeUtils.java:157)
      at com.google.appengine.api.datastore.Query$FilterPredicate.&lt;init&gt;(Query.java:549)
      at com.google.appengine.api.datastore.Query.addFilter(Query.java:235)
      at org.datanucleus.store.appengine.query.DatastoreQuery.addLeftPrimaryExpression(DatastoreQuery.java:1138)
      at org.datanucleus.store.appengine.query.DatastoreQuery.handleContainsOperation(DatastoreQuery.java:987)
      at org.datanucleus.store.appengine.query.DatastoreQuery.addExpression(DatastoreQuery.java:880)
      at org.datanucleus.store.appengine.query.DatastoreQuery.addFilters(DatastoreQuery.java:827)
      at org.datanucleus.store.appengine.query.DatastoreQuery.performExecute(DatastoreQuery.java:228)
      at org.datanucleus.store.appengine.query.JDOQLQuery.performExecute(JDOQLQuery.java:89)
      at org.datanucleus.store.query.Query.executeQuery(Query.java:1489)
      at org.datanucleus.store.query.Query.executeWithArray(Query.java:1371)
      at org.datanucleus.jdo.JDOQuery.execute(JDOQuery.java:243)
      at com.softamo.pelicamo.server.MainServiceImpl.getJDOPayments(MainServiceImpl.java:947)
      at com.softamo.pelicamo.server.MainServiceImpl.getIncomeSummaries(MainServiceImpl.java:817)
      at com.softamo.pelicamo.server.IncomeServiceTest.testGetIncomeSummaries(IncomeServiceTest.java:62)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
      at java.lang.reflect.Method.invoke(Method.java:597)
      at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
      at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
      at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
      at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
      at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:73)
      at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:46)
      at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:180)
      at org.junit.runners.ParentRunner.access$000(ParentRunner.java:41)
      at org.junit.runners.ParentRunner$1.evaluate(ParentRunner.java:173)
      at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
      at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
      at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
      at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
      at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
      at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
  </code></pre>