[hibernate-issues] [Hibernate-JIRA] Commented: (HSEARCH-115) Add a default value for indexing null value

[Sanne Grinovero (JIRA)]

    [ http://opensource.atlassian.com/projects/hibernate/browse/HSEARCH-115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=38967#action_38967 ] 

Sanne Grinovero commented on HSEARCH-115:
-----------------------------------------

Just to illustrate what I was thinking about (didn't test, I might be missing something), I paste the code;
basically when reading the annotations we can wrap any TwoWayFieldBridge we would otherwise use (if two-way)
with an adapter like this:

{noformat}

public class NullEncodingTwoWayFieldBridge implements TwoWayFieldBridge {

	private final TwoWayFieldBridge fieldBridge;
	private final String nullMarker;
	
	public NullEncodingTwoWayFieldBridge(TwoWayFieldBridge fieldBridge, String nullMarker) {
		this.fieldBridge = fieldBridge;
		this.nullMarker = nullMarker;
	}

	public Object get(String name, Document document) {
		Field field = document.getField( name );
		String stringValue = field.stringValue();
		if ( nullMarker.equals( stringValue ) ) {
			return null;
		}
		else {
			return fieldBridge.get( name, document );
		}
	}

	public String objectToString(Object object) {
		if ( object == null ) {
			return nullMarker;
		}
		else {
			return fieldBridge.objectToString( object );
		}
	}

	public void set(String name, Object value, Document document, LuceneOptions luceneOptions) {
		fieldBridge.set( name, value, document, luceneOptions );
	}

}

{noformat}
Only downside is that field.stringValue() might be invoked twice for the same field, in both this impl and the wrapped impl; afaik that shouldn't be expensive.

Considering "a bridge is free to do many things" (quoting Emmanuel), do you foresee breaking anything?

> Add a default value for indexing null value
> -------------------------------------------
>
>                 Key: HSEARCH-115
>                 URL: http://opensource.atlassian.com/projects/hibernate/browse/HSEARCH-115
>             Project: Hibernate Search
>          Issue Type: Improvement
>          Components: mapping
>            Reporter: Julien Brulin
>            Assignee: Hardy Ferentschik
>             Fix For: 3.3.0
>
>
> Hi,
> Null elements are not indexed by lucene then it's not easy to use a nullable property in lucene query.
> I have a TagTranslation entity in my model with a nullable property language. In this case null is used as default language for tag translation.
> Each translation may have many variations like synonyms. 
> Because I can specified a default value for null value in the @Field annotation like this @Field(index=Index.UN_TOKENIZED, store=Store.NO, default='null'), i can't search a cat tag with a default translation like this : +value:cat* +lang:null 
> {code}
> @Entity()
> @Table(name="indexing_tag_trans")
> @org.hibernate.annotations.Cache(usage=org.hibernate.annotations.CacheConcurrencyStrategy.READ_WRITE)
> @Indexed
> public class TagTranslation implements java.io.Serializable {
>     private static final long serialVersionUID = -1065316566731456110L;
> 	
>     @Id
>     @GeneratedValue(strategy=GenerationType.IDENTITY)
>     @DocumentId
>     private Integer id;
>    
>     @Field(index=Index.UN_TOKENIZED, store=Store.NO)
>     private String language;
>     
>     @Field(index=Index.TOKENIZED, store=Store.YES)
>     private String value;
>     
>     @OneToMany(cascade=CascadeType.ALL, fetch=FetchType.LAZY)
>     @org.hibernate.annotations.Fetch(org.hibernate.annotations.FetchMode.SUBSELECT)
>     @JoinColumn(name="translation_id")
>     @IndexedEmbedded
>     private List<TagVariation> variations = new LinkedList<TagVariation>();
>   
>     public TagTranslation() { }
> ...
> {code}
> What do you think about that ?
> Ps: sorry for english write, i am a french guy.

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