/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using IndexReader = Lucene.Net.Index.IndexReader;
using FieldCache = Lucene.Net.Search.FieldCache;
namespace Lucene.Net.Search.Function
{
/// Expert: obtains the ordinal of the field value from the default Lucene
/// FieldCache using getStringIndex()
/// and reverses the order.
///
/// The native lucene index order is used to assign an ordinal value for each field value.
///
/// Field values (terms) are lexicographically ordered by unicode value, and numbered starting at 1.
///
/// Example of reverse ordinal (rord):
///
If there were only three field values: "apple","banana","pear"
///
then rord("apple")=3, rord("banana")=2, ord("pear")=1
///
/// WARNING:
/// rord() depends on the position in an index and can thus change
/// when other documents are inserted or deleted,
/// or if a MultiSearcher is used.
///
///
/// WARNING: The status of the Search.Function package is experimental.
/// The APIs introduced here might change in the future and will not be
/// supported anymore in such a case.
///
/// NOTE: with the switch in 2.9 to segment-based
/// searching, if is invoked with a
/// composite (multi-segment) reader, this can easily cause
/// double RAM usage for the values in the FieldCache. It's
/// best to switch your application to pass only atomic
/// (single segment) readers to this API.
///
[Serializable]
public class ReverseOrdFieldSource:ValueSource
{
private class AnonymousClassDocValues:DocValues
{
public AnonymousClassDocValues(int end, int[] arr, ReverseOrdFieldSource enclosingInstance)
{
InitBlock(end, arr, enclosingInstance);
}
private void InitBlock(int end, int[] arr, ReverseOrdFieldSource enclosingInstance)
{
this.end = end;
this.arr = arr;
this.enclosingInstance = enclosingInstance;
}
private int end;
private int[] arr;
private ReverseOrdFieldSource enclosingInstance;
public ReverseOrdFieldSource Enclosing_Instance
{
get
{
return enclosingInstance;
}
}
/*(non-Javadoc) field whose values reverse order is used.
///
public ReverseOrdFieldSource(System.String field)
{
this.field = field;
}
/*(non-Javadoc)