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JohannesRabauerJohannesRabauer
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Added docs and demos for lazy
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‎CHANGELOG.md‎

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# 1.0.4
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* Added possibility to use multiple storages
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* Added Lazy support
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# 1.0.3
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‎docs/modules/ROOT/nav.adoc‎

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* xref:installation.adoc[Installation]
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* xref:configuration.adoc[Configuration]
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* xref:working-copies.adoc[Working Copies]
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* xref:lazies.adoc[Lazy References]
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* xref:migration.adoc[Migration]
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* xref:known-issues.adoc[Known issues]

‎docs/modules/ROOT/pages/known-issues.adoc‎

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= Known issues
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== Lazy references
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One of the core features of EclipseStore is its https://docs.eclipsestore.io/manual/storage/loading-data/lazy-loading/index.html[Lazy references].
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Unfortunately this requires our library to implement some kind of proxy.
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That's something that takes a lot of effort to implement in our {product-name}.
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We created https://github.com/xdev-software/spring-data-eclipse-store/issues/31[an issue] for that but right now we *do not support Lazy references*.
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== Query annotations
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In Spring-Data-JPA you can write a Query over methods of repositories like this:

‎docs/modules/ROOT/pages/lazies.adoc‎

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= Lazy References
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Lazy Loading is an essential part of EclipseStore.
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The basic mechanism is best explained in the https://docs.eclipsestore.io/manual/storage/loading-data/lazy-loading/index.html[EclipseStore-Docs]. +
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In essence java objects which are wrapped in a *Lazy-Reference are not loaded with the startup of the EclipseStore-Storage but only if ``get()`` is called* on them.
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Lazy References are essential for big data sets that can't get loaded into memory.
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Since {product-name} operates with xref:working-copies.adoc[working copies] using the EclipseStore-Lazy-References is not possible.
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All Lazy References would be resolved and loaded into memory anyway.
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That's why we implemented ``SpringDataEclipseStoreLazy``. +
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The usage is the same as with the EclipseStore-Lazies, but they are handled very differently.
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Simply wrap any kind of java object in the SpringDataEclipseStoreLazy-Wrapper and the wrapped object has a lazy loading behaviour.
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CAUTION: Lazy-References are not only loaded when needed, but also https://docs.eclipsestore.io/manual/storage/loading-data/lazy-loading/clearing-lazy-references.html#automatically[*cleared when they are no longer needed*]!
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Example: ``SpringDataEclipseStoreLazy.build(new HashMap<String, Pet>())``
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[source,java,title="https://github.com/xdev-software/spring-data-eclipse-store/tree/develop/spring-data-eclipse-store-demo/src/main/java/software/xdev/spring/data/eclipse/store/demo/complex/owner/Owner.java[Example from complex demo]"]
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----
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package software.xdev.spring.data.eclipse.store.demo.complex.owner;
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//...
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import software.xdev.spring.data.eclipse.store.repository.lazy.SpringDataEclipseStoreLazy;
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public class Owner extends Person
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{
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private String address;
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private Lazy<List<Pet>> pets = SpringDataEclipseStoreLazy.build(new ArrayList<>());
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//...
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----
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== Internas
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SpringDataEclipseStoreLazies work as a proxy for the EclipseStore-Lazies.
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As far as EclipseStore is concerned, a SpringDataEclipseStoreLazy-Object is a normal Java object that contains a Lazy-Reference.
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But when {product-name} creates the working copy, *the SpringDataEclipseStoreLazy-Reference is not resolved* but instead only a reference to the original Lazy-Object in EclipseStore is loaded.
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As soon as ``get()`` is called on the SpringDataEclipseStoreLazy, a *new working copy of the lazy object* is created.

‎spring-data-eclipse-store-demo/src/main/java/software/xdev/spring/data/eclipse/store/demo/complex/ComplexDemoApplication.java‎

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);
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}
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);
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LOG.info("----Owner-Lazy Pet loading----");
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this.ownerRepository.findAll().forEach(
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o -> o.getPets().forEach(
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pet -> LOG.info(String.format(
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"Pet %s has owner %s %s",
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pet.getName(),
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o.getFirstName(),
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o.getLastName()))
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)
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);
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}
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private static Visit createVisit()

‎spring-data-eclipse-store-demo/src/main/java/software/xdev/spring/data/eclipse/store/demo/complex/owner/Owner.java‎

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import java.util.List;
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import java.util.Optional;
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import org.eclipse.serializer.reference.Lazy;
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import org.springframework.core.style.ToStringCreator;
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import org.springframework.util.Assert;
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import software.xdev.spring.data.eclipse.store.demo.complex.model.Person;
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import software.xdev.spring.data.eclipse.store.repository.lazy.SpringDataEclipseStoreLazy;
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public class Owner extends Person
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private String telephone;
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private final List<Pet> pets = new ArrayList<>();
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private Lazy<List<Pet>> pets = SpringDataEclipseStoreLazy.build(new ArrayList<>());
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public String getAddress()
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{
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public List<Pet> getPets()
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{
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return this.pets;
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return this.pets.get();
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}
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public void setPets(final List<Pet> pets)
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{
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this.pets = SpringDataEclipseStoreLazy.build(pets);
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}
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public void addPet(final Pet pet)

‎spring-data-eclipse-store-demo/src/main/java/software/xdev/spring/data/eclipse/store/demo/complex/owner/OwnerRepository.java‎

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*/
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package software.xdev.spring.data.eclipse.store.demo.complex.owner;
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import java.util.List;
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import org.springframework.data.domain.Page;
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import org.springframework.data.domain.Pageable;
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import org.springframework.data.repository.Repository;
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Page<Owner> findAll(Pageable pageable);
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List<Owner> findAll();
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void deleteAll();
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}

‎spring-data-eclipse-store/src/main/java/software/xdev/spring/data/eclipse/store/repository/lazy/SpringDataEclipseStoreLazy.java‎

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* {@link Lazy}-Wrapper!</b> Because SDES is making working copies of the stored data, the {@link Lazy} does not work as
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* expected. Instead, use this Wrapper. It brings the same functionality as the native {@link Lazy}-Wrapper but works
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* with working copies.
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*
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* @param <T> the type of the lazily referenced element
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*/
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public interface SpringDataEclipseStoreLazy<T> extends Lazy<T>
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{
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}
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/**
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* This class is very complex and its various membervariables all have their reason to exist. This code is very
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* This class is very complex and its various member variables all have their reason to exist. This code is very
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* difficult to read due to its the functionality explained in the {@link SpringDataEclipseStoreLazyBinaryHandler}.
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*
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* @param <T>
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* @param <T> the type of the lazily referenced element
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*/
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@SuppressWarnings({"java:S2065", "checkstyle:FinalClass"})
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class Default<T> implements SpringDataEclipseStoreLazy<T>
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{
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private T objectToBeWrapped;
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private Lazy<T> wrappedLazy;
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private long objectId = Swizzling.notFoundId();
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private transient ObjectSwizzling loader;
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private transient WorkingCopier<T> copier;
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private transient boolean isStored = false;
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private transient boolean isStored;
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private Default(final Lazy<T> lazySubject)
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{
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return this.wrappedLazy;
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}
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@SuppressWarnings("unchecked")
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private Lazy<T> createNewDefaultLazyWithClearableReference()
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{
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Objects.requireNonNull(this.loader);
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Objects.requireNonNull(this.objectId);
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Objects.requireNonNull(this.copier);
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final T originalInstance = (T)this.loader.getObject(this.objectId);
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);
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}
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@SuppressWarnings("all")
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public static final Class<SpringDataEclipseStoreLazy.Default<?>> genericType()
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{
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// no idea how to get ".class" to work otherwise in conjunction with generics.
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return (Class)SpringDataEclipseStoreLazy.Default.class;
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}
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@Override
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public T get()
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{
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@Override
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public long objectId()
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{
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if(this.wrappedLazy != null && this.wrappedLazy instanceof Lazy.Default<T>)
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if(this.wrappedLazy != null && this.wrappedLazy instanceof final Lazy.Default<T> wrappedTypedLazy)
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{
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return ((Lazy.Default<T>)this.wrappedLazy).objectId();
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return wrappedTypedLazy.objectId();
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}
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return this.objectId;
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}
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@Override
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public SpringDataEclipseStoreLazy<T> copyWithReference()
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{
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final SpringDataEclipseStoreLazy.Default newLazy = new SpringDataEclipseStoreLazy.Default(
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final SpringDataEclipseStoreLazy.Default<T> newLazy = new SpringDataEclipseStoreLazy.Default<>(
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this.objectId(),
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this.loader,
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this.copier
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return newLazy;
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// TODO is this necessary?
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@Override
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public void unlink()
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{
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try
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{
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if(this.wrappedLazy != null)
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{
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final Lazy.Default wrappedDefaultLazy = (Lazy.Default)this.wrappedLazy;
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final Lazy.Default<T> wrappedDefaultLazy = (Lazy.Default<T>)this.wrappedLazy;
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wrappedDefaultLazy.$unlink();
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final Field objectIdField = Lazy.Default.class.getDeclaredField("objectId");
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try(final FieldAccessModifier fam = FieldAccessModifier.prepareForField(
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try(final FieldAccessModifier<Lazy.Default<T>> fam = FieldAccessModifier.prepareForField(
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objectIdField,
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wrappedDefaultLazy))
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{

‎spring-data-eclipse-store/src/main/java/software/xdev/spring/data/eclipse/store/repository/lazy/SpringDataEclipseStoreLazyBinaryHandler.java‎

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final WorkingCopier<?> copier)
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{
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super(
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SpringDataEclipseStoreLazy.Default.genericType(),
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(Class)SpringDataEclipseStoreLazy.Default.class,
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CustomFields(
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CustomField(Object.class, "lazySubject"),
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CustomField(Object.class, "unwrappedSubject")

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