CollectionBinder.java 文件源码

private void defineFetchingStrategy() {
    LazyCollection lazy = property.getAnnotation( LazyCollection.class );
    Fetch fetch = property.getAnnotation( Fetch.class );
    OneToMany oneToMany = property.getAnnotation( OneToMany.class );
    ManyToMany manyToMany = property.getAnnotation( ManyToMany.class );
    ElementCollection elementCollection = property.getAnnotation( ElementCollection.class ); //jpa 2
    ManyToAny manyToAny = property.getAnnotation( ManyToAny.class );
    FetchType fetchType;
    if ( oneToMany != null ) {
        fetchType = oneToMany.fetch();
    }
    else if ( manyToMany != null ) {
        fetchType = manyToMany.fetch();
    }
    else if ( elementCollection != null ) {
        fetchType = elementCollection.fetch();
    }
    else if ( manyToAny != null ) {
        fetchType = FetchType.LAZY;
    }
    else {
        throw new AssertionFailure(
                "Define fetch strategy on a property not annotated with @ManyToOne nor @OneToMany nor @CollectionOfElements"
        );
    }
    if ( lazy != null ) {
        collection.setLazy( !( lazy.value() == LazyCollectionOption.FALSE ) );
        collection.setExtraLazy( lazy.value() == LazyCollectionOption.EXTRA );
    }
    else {
        collection.setLazy( fetchType == FetchType.LAZY );
        collection.setExtraLazy( false );
    }
    if ( fetch != null ) {
        if ( fetch.value() == org.hibernate.annotations.FetchMode.JOIN ) {
            collection.setFetchMode( FetchMode.JOIN );
            collection.setLazy( false );
        }
        else if ( fetch.value() == org.hibernate.annotations.FetchMode.SELECT ) {
            collection.setFetchMode( FetchMode.SELECT );
        }
        else if ( fetch.value() == org.hibernate.annotations.FetchMode.SUBSELECT ) {
            collection.setFetchMode( FetchMode.SELECT );
            collection.setSubselectLoadable( true );
            collection.getOwner().setSubselectLoadableCollections( true );
        }
        else {
            throw new AssertionFailure( "Unknown FetchMode: " + fetch.value() );
        }
    }
    else {
        collection.setFetchMode( AnnotationBinder.getFetchMode( fetchType ) );
    }
}