• Compass
  http://www.compass-project.org/
• Demo video
  http://www.kimchy.org/searchable-google-appengine-with-compass/

How to use

1. Download module
   1. http://build.compass-project.org/ of Compass Trunk of select Nightly Build.
   2. Results Page built "Artifacts" Click, "Release" to select.
   3. Likely to be a list of files, from which to download the compass-2.3.0-beta1.zip.
2. Module Placement
   1. Unzip the downloaded module, add the following file CLASSPATH (Google Plugin If you use the "war / WEB-INF / lib" copy, Eclipse projects also add to the Build path.)
      1. commons-logging.jar
      2. compass-2.3.0-beta1.jar
      3. lucene-core.jar

Initialization

The demonstration video, PMF.java imitation because it was initialized with a static initializer.

• Class "@ Searchable" to qualify.
• Entity can be used as the primary key field "@ SearchableId" to qualify.
  • However, "com.google.appengine.api.datastore.Key" is not bound to accept because, as I have below.
    
    @ SearchableId

    public Long getKeyValue () (

        return key.getId ();

    )

     
• The search field to use as "@ SearchableProperty" to qualify.
  • However, "com.google.appengine.api.datastore.Text" is not bound to accept because, as I have below.
    
    @ SearchableProperty

    public String getContent1String () (

        if (content1 == null) (

            return "";

        )

        return content1.getValue ();

    )

     
• @ SearchableProperty (name = "Field Name") in the class Entity and attribute names can I use different name too.
  • Also, org.apache.lucene.document.Field attributes that can be used when creating.

Search

If you want to search for the name Field

If you specify a search for Kind

• Search criteria alias: Kind Name (Class.getSimpleName ())

Resona

• When you save through JDO, @ SearchableProperty were added using the getter and Field Index to create value, it seems to work.
  • Entity class, using annotations to Index If you do add to the information (that is what I wrote on this page), there always needs to be saved through JDO. LowLevelAPI saved and does not create Entity Index for the (natural or ....)
  • Unowned other Entity relationship holds a reference to its value after the Index can also fetch for it created. , But always return the value of persistence when the getter must return a value, so actually, the "fetch the referenced Entity before saving to keep you" need.
    

    unowned

    @ Persistence private Key otherEntityKey;

     

    @ NotPersistence private OtherEntity otherEntity;

     

    @ SearchablePropperty (name = "otherEntity")

    public Sting getOtherEntityValue () (

      return otherEntity! = null? otherEntity.getValue (): "";

    )
• Entity Index for the creation, no one could get for a separate?
  • Once implemented the Task Queue Java platform, Index will be delayed for creating Entity can only be good ... and behavior.
    • Compass TaskQueue side and I may well be expected to support.
• Want control over the creation of the Index
  • Without CompassGps, Compass.Getsearchengineindexmanager() call control.
    • Because some of the lucene subinterface for the smaller may be able to use it?
  • Entity is a separate index to Compass.Openindexsession() calls to control
•  create dynamic query
  • Compass.queryBuilder () Get the querybuilder. 良Shinani later.
  • between, eq, ge, gt, le, le, and, or, like, wildcard and one with an array.
  •  CompassMultiPropertyQueryStringBuilder or search over multiple properties at once
  • CompassSearchSession.find (queryString) internally CompassSearchSession.queryBuilder (). QueryString (queryString). ToQuery (). Hits () have.
     
• Add to sort search
  • Compassquery .Addsort(String propertyName, Compassquery.sortdirection direction) and the like.
• limit, offset to add
  • I looked, was not sure.CompassHits todetach(int from, int size) so that, if this 1-2 times will reduce Data itself. I do not mean much.
• Highlight the text you wish to search results
  • Search engines highlight text in general are presented as fragments around search terms that best match (for example, place a few hundred characters) lucene is called in other bestFragment.
  • The method to get this fragment CompassHits.highlighter (i). Fragment (propertyName) 

    To obtain fragments of the highlights

        CompassSearchSession searchSession = getCompass (). OpenSearchSession ();
        CompassHits hits = searchSession.find (text);

        int length = hits.getLength ();

        if (length> 0) (

         for (int i = 0; i <length; i + +) (

          / / Here are widespread PR highlights the string.

          String fragment = hits.highlighter (i). Fragment ("pr");

          Resource resource = hits.resource (i);
         )
        )
        return results;
  •  Wicket to display in IData highlighter in one form or another will take to get the fragment.