I have implemented a subclass ImageBlob of BlobImpl in order to store images in the db. This works perfectly if I map the class containing this blob with <class>. However, since most of my persistent classes are subclasses of PersistentObject I wanted to map it as a <joined-subclasss> as soon as I do that however I get an exception when saving the object saying that I can not manipulate a blob outside a session.
But the session is till open at the moment of the save! Anyway, what's the difference? In my opinion behaviour should be the same but nope :(
Here is the code:
Code:
session.beginTransaction();
Exercise exercise = ExerciseFactory.getNewExercise();
DataItem variantDataItem = Data.VARIANT.add("variant");
exercise.addVariant(variantDataItem);
Variant variant = exercise.getVariant(variantDataItem);
BufferedImage image;
variant.setAssignment("assignment");
variant.setStartPositionDetail("startPositionDetail");
variant.setType(VariantType.ASSIGNMENT);
image = variant.getImage(); // if the variant does not yet have an image the default image is loaded from file.
exercise.save(); // this saves the variant too and generates the error.
session.getTransaction().commit();
The ImageBlob class:
Code:
public class ImageBlob extends BlobImpl {
public ImageBlob(Blob blob) throws SQLException {
super(blob.getBytes(1, (int) blob.length())); // This is where it goes wrong!! ... well, when using <joined-subclass>, not when using <class>
}
public ImageBlob(BufferedImage image) {
super(getBytes(image));
}
public BufferedImage getImage() {
try {
return ImageIO.read(getBinaryStream());
}
catch (IOException exception) {
// TODO Auto-generated catch block
exception.printStackTrace();
return null;
}
catch (SQLException exception) {
// TODO Auto-generated catch block
exception.printStackTrace();
return null;
}
}
public void setImage(BufferedImage image) {
try {
setBytes(1L, getBytes(image));
}
catch (SQLException exception) {
// TODO Auto-generated catch block
exception.printStackTrace();
}
}
public static byte[] getBytes(BufferedImage image) {
try {
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(image, "jpg", byteArrayOutputStream);
byteArrayOutputStream.flush();
return byteArrayOutputStream.toByteArray();
}
catch (IOException exception) {
// TODO Auto-generated catch block
exception.printStackTrace();
return null;
}
}
}
The <joined-subclass> mapping file (this one does NOT work)
Code:
<hibernate-mapping package="be.bloso.vetrasoft.model.exercise">
<joined-subclass name="Variant"
extends="be.bloso.vetrasoft.model.PersistentObject"
table="VARIANT">
<key column="id" />
<property name="startPositionDetail" />
<property name="assignment" />
<property name="standard" />
<property name="type" />
<property name="imageBlob" type="blob" lazy="true" />
<many-to-one name="parent" class="ExerciseImpl" fetch="select" />
<many-to-one name="variantDataItem" class="be.bloso.vetrasoft.model.application.DataItem" fetch="select" />
</joined-subclass>
</hibernate-mapping>
The <class> version. This one DOES work
Code:
<hibernate-mapping package="be.bloso.vetrasoft.model.exercise">
<class name="Variant" table="VARIANT">
<id name="id" column="DATAITEM_ID">
<generator class="hilo" />
</id>
<property name="startPositionDetail" />
<property name="assignment" />
<property name="standard" />
<property name="type" />
<property name="imageBlob" type="blob" lazy="true" />
<many-to-one name="parent" class="ExerciseImpl" fetch="select" />
<many-to-one name="variantDataItem" class="be.bloso.vetrasoft.model.application.DataItem" fetch="select" />
</class>
</hibernate-mapping>
The stack trace:
Code:
org.hibernate.PropertyAccessException: Exception occurred inside setter of be.bloso.vetrasoft.model.exercise.Variant.imageBlob
at org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:89)
at org.hibernate.tuple.entity.AbstractEntityTuplizer.setPropertyValues(AbstractEntityTuplizer.java:352)
at org.hibernate.tuple.entity.PojoEntityTuplizer.setPropertyValues(PojoEntityTuplizer.java:232)
at org.hibernate.persister.entity.AbstractEntityPersister.setPropertyValues(AbstractEntityPersister.java:3580)
at org.hibernate.event.def.AbstractSaveEventListener.performSaveOrReplicate(AbstractSaveEventListener.java:300)
at org.hibernate.event.def.AbstractSaveEventListener.performSave(AbstractSaveEventListener.java:204)
at org.hibernate.event.def.AbstractSaveEventListener.saveWithGeneratedId(AbstractSaveEventListener.java:144)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.saveWithGeneratedOrRequestedId(DefaultSaveOrUpdateEventListener.java:210)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.entityIsTransient(DefaultSaveOrUpdateEventListener.java:195)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.performSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:117)
at org.hibernate.event.def.DefaultSaveOrUpdateEventListener.onSaveOrUpdate(DefaultSaveOrUpdateEventListener.java:93)
at org.hibernate.impl.SessionImpl.fireSaveOrUpdate(SessionImpl.java:535)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:527)
at org.hibernate.impl.SessionImpl.saveOrUpdate(SessionImpl.java:523)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:342)
at $Proxy7.saveOrUpdate(Unknown Source)
at be.bloso.vetrasoft.model.PersistentObject.save(PersistentObject.java:57)
at be.bloso.vetrasoft.model.exercise.Variant.save(Variant.java:84)
at be.bloso.vetrasoft.model.exercise.ExerciseImpl.save(ExerciseImpl.java:91)
at be.bloso.vetrasoft.model.application.DatabaseTest.testVariant(DatabaseTest.java:272)
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$1.evaluate(ParentRunner.java:173)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.ParentRunner.run(ParentRunner.java:220)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:46)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.hibernate.property.BasicPropertyAccessor$BasicSetter.set(BasicPropertyAccessor.java:66)
... 47 more
Caused by: java.lang.UnsupportedOperationException: Blob may not be manipulated from creating session
at org.hibernate.lob.BlobImpl.excep(BlobImpl.java:127)
at org.hibernate.lob.BlobImpl.getBytes(BlobImpl.java:73)
at be.bloso.vetrasoft.model.application.ImageBlob.<init>(ImageBlob.java:25)
at be.bloso.vetrasoft.model.exercise.Variant.setImageBlob(Variant.java:204)
... 52 more
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