Is it possible to do a date based query time boost in Compass?

Question

I'm trying to get a query-time boost on recent items in a Compass index. I have tried using a property on my class mapping, but this only seems to affect the boost during index-time, not query-time.

Any ideas?

Answer 1

            DefaultCompassQuery query = (DefaultCompassQuery) compassBuilderQuery.toQuery();
            query.setTypes( types.toArray( new Class[types.size()] ) );
            LuceneSearchEngineQuery searchEngineQuery = (LuceneSearchEngineQuery) query.getSearchEngineQuery();
            final SimpleDateFormat sdf = new SimpleDateFormat( "yyyyMMddHHmmss" );
            final long timeInMillis = Calendar.getInstance().getTimeInMillis();
            ValueSourceQuery valSrcQuery = new ValueSourceQuery( new ValueSource() {

                private static final long serialVersionUID = 1L;

                @Override
                public int hashCode() {
                    return System.identityHashCode( this );
                }

                @Override
                public DocValues getValues( final IndexReader reader ) throws IOException {
                    return new DocValues() {

                        @Override
                        public float floatVal( int doc ) {
                            try {
                                Document document = reader.document( doc );
                                Field field = document.getField( "date" );
                                if (null != field) {
                                    Date parse = sdf.parse( field.stringValue() );

                                    long t = timeInMillis - parse.getTime();

                                    float f = (1.0f / (t * (1.0f / TimeUnit.DAYS.toMillis( 30 )) + 1.0f));
                                    if (logger.isDebugEnabled()) {
                                        logger.debug( "Date match: " + parse.toString() );
                                        logger.debug( "Calculated date boost as: " + f + " for doc id: " + doc );
                                    }
                                    return f;
                                }
                            } catch (CorruptIndexException e) {
                                e.printStackTrace();
                            } catch (IOException e) {
                                e.printStackTrace();
                            } catch (ParseException e) {
                                e.printStackTrace();
                            }
                            return 1.0f;
                        }

                        @Override
                        public String toString( int doc ) {
                            return description() + "=" + strVal( doc );
                        }

                    };
                }

                @Override
                public boolean equals( Object o ) {
                    return this == o;
                }

                @Override
                public String description() {
                    return "[boost: date]";
                }
            } );
            CustomScoreQuery sq = new CustomScoreQuery( searchEngineQuery.getQuery(), valSrcQuery );
            searchEngineQuery.setQuery( sq );

Where 'date' is a date field on your document that you want to boost and compassBuilderQuery is a query you have generated with the compass query builder. You can also tweak the '30' up there to make the dates boosted less or more based on their age.