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BooleanFilter.cs
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BooleanFilter.cs
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// Lucene version compatibility level 4.8.1
using Lucene.Net.Diagnostics;
using Lucene.Net.Index;
using Lucene.Net.Search;
using Lucene.Net.Util;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using JCG = J2N.Collections.Generic;
namespace Lucene.Net.Queries
{
/*
* 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.
*/
/// <summary>
/// A container <see cref="Filter"/> that allows Boolean composition of <see cref="Filter"/>s.
/// <see cref="Filter"/>s are allocated into one of three logical constructs;
/// SHOULD, MUST NOT, MUST
/// The results <see cref="Filter"/> BitSet is constructed as follows:
/// SHOULD Filters are OR'd together
/// The resulting <see cref="Filter"/> is NOT'd with the NOT <see cref="Filter"/>s
/// The resulting <see cref="Filter"/> is AND'd with the MUST <see cref="Filter"/>s
/// </summary>
public class BooleanFilter : Filter, IEnumerable<FilterClause>
{
private readonly IList<FilterClause> clauses = new JCG.List<FilterClause>();
/// <summary>
/// Returns the a <see cref="DocIdSetIterator"/> representing the Boolean composition
/// of the filters that have been added.
/// </summary>
public override DocIdSet GetDocIdSet(AtomicReaderContext context, IBits acceptDocs)
{
FixedBitSet res = null;
AtomicReader reader = context.AtomicReader;
bool hasShouldClauses = false;
foreach (FilterClause fc in clauses)
{
if (fc.Occur == Occur.SHOULD)
{
hasShouldClauses = true;
DocIdSetIterator disi = GetDISI(fc.Filter, context);
if (disi == null)
{
continue;
}
if (res == null)
{
res = new FixedBitSet(reader.MaxDoc);
}
res.Or(disi);
}
}
if (hasShouldClauses && res == null)
{
return null;
}
foreach (FilterClause fc in clauses)
{
if (fc.Occur == Occur.MUST_NOT)
{
if (res == null)
{
if (Debugging.AssertsEnabled) Debugging.Assert(!hasShouldClauses);
res = new FixedBitSet(reader.MaxDoc);
res.Set(0, reader.MaxDoc); // NOTE: may set bits on deleted docs
}
DocIdSetIterator disi = GetDISI(fc.Filter, context);
if (disi != null)
{
res.AndNot(disi);
}
}
}
foreach (FilterClause fc in clauses)
{
if (fc.Occur == Occur.MUST)
{
DocIdSetIterator disi = GetDISI(fc.Filter, context);
if (disi == null)
{
return null; // no documents can match
}
if (res == null)
{
res = new FixedBitSet(reader.MaxDoc);
res.Or(disi);
}
else
{
res.And(disi);
}
}
}
return BitsFilteredDocIdSet.Wrap(res, acceptDocs);
}
private static DocIdSetIterator GetDISI(Filter filter, AtomicReaderContext context)
{
// we dont pass acceptDocs, we will filter at the end using an additional filter
DocIdSet set = filter.GetDocIdSet(context, null);
return set?.GetIterator();
}
/// <summary>
/// Adds a new <see cref="FilterClause"/> to the Boolean <see cref="Filter"/> container </summary>
/// <param name="filterClause"> A <see cref="FilterClause"/> object containing a <see cref="Filter"/> and an <see cref="Occur"/> parameter </param>
public virtual void Add(FilterClause filterClause)
{
clauses.Add(filterClause);
}
public void Add(Filter filter, Occur occur)
{
Add(new FilterClause(filter, occur));
}
/// <summary>
/// Gets the list of clauses
/// </summary>
public virtual IList<FilterClause> Clauses => clauses;
/// <summary>
/// Returns an iterator on the clauses in this query. It implements the <see cref="IEnumerable{T}"/> interface to
/// make it possible to do:
/// <code>for (FilterClause clause : booleanFilter) {}</code>
/// </summary>
public IEnumerator<FilterClause> GetEnumerator()
{
return Clauses.GetEnumerator();
}
public override bool Equals(object obj)
{
if (this == obj)
{
return true;
}
if ((obj == null) || (obj.GetType() != this.GetType()))
{
return false;
}
var other = (BooleanFilter)obj;
return clauses.Equals(other.clauses);
}
public override int GetHashCode()
{
return 657153718 ^ clauses.GetHashCode();
}
/// <summary>
/// Prints a user-readable version of this <see cref="Filter"/>. </summary>
public override string ToString()
{
var buffer = new StringBuilder("BooleanFilter(");
int minLen = buffer.Length;
foreach (FilterClause c in clauses)
{
if (buffer.Length > minLen)
{
buffer.Append(' ');
}
buffer.Append(c);
}
return buffer.Append(')').ToString();
}
// LUCENENET specific
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
}
}