AgeFieldSource

AgeFieldSource.java

public class AgeFieldSource extends FieldCacheSource {
  private int now;
  public AgeFieldSource(String field) {
    super(field);
    now = (int)(System.currentTimeMillis() / 1000);
  }

  @Override
  public boolean cachedFieldSourceEquals(FieldCacheSource other) {
    return other.getClass() == MyFieldSource.class;
  }

  @Override
  public int cachedFieldSourceHashCode() {
    return Integer.class.hashCode();
  }

  @Override
  public DocValues getCachedFieldValues(FieldCache cache, String field, IndexReader reader) throws IOException {
    int[] times     = cache.getInts(reader, field);
    float[] weights = new float[times.length];
    for (int i=0; i<times.length; i++) {
      // Here be the nuts and bolts
      weights[i] = new Double(1/Math.log((now - times[i]) / 3600)).floatValue();
    }

    final float[] arr = weights;
    return new DocValues() {
      public float floatVal(int doc) {
        return (float) arr[doc];
      }

      public int intVal(int doc) {
        return (int) arr[doc];
      }

      public String toString(int doc) {
        return description() + '=' + intVal(doc);
      }
    };
  }
}