/*
* Copyright 2004 The Apache Software Foundation
*
* Licensed 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 IndexReaderLucene.Net.Index.IndexReader;
using QueryLucene.Net.Search.Query;
using ToStringUtilsLucene.Net.Util.ToStringUtils;
namespace Lucene.Net.Search.Spans{
/// <summary>Removes matches which overlap with another SpanQuery. </summary>
[Serializable]
public class SpanNotQuery : SpanQuery
{
private class AnonymousClassSpans : Spans
{
public AnonymousClassSpans(Lucene.Net.Index.IndexReader reader, SpanNotQuery enclosingInstance)
{
InitBlock(reader, enclosingInstance);
}
private void InitBlock(Lucene.Net.Index.IndexReader reader, SpanNotQuery enclosingInstance)
{
this.reader = reader;
this.enclosingInstance = enclosingInstance;
includeSpans = Enclosing_Instance.include.GetSpans(reader);
excludeSpans = Enclosing_Instance.exclude.GetSpans(reader);
}
private Lucene.Net.Index.IndexReader reader;
private SpanNotQuery enclosingInstance;
public SpanNotQuery Enclosing_Instance
{
get
{
return enclosingInstance;
}
}
private Spans includeSpans;
private bool moreInclude = true;
private Spans excludeSpans;
private bool moreExclude = true;
public virtual bool Next()
{
if (moreInclude)
// move to next include
moreInclude = includeSpans.Next();
while (moreInclude && moreExclude)
{
if (includeSpans.Doc() > excludeSpans.Doc())
// skip exclude
moreExclude = excludeSpans.SkipTo(includeSpans.Doc());
while (moreExclude && includeSpans.Doc() == excludeSpans.Doc() && excludeSpans.End() <= includeSpans.Start())
{
moreExclude = excludeSpans.Next(); // increment exclude
}
if (!moreExclude || includeSpans.Doc() != excludeSpans.Doc() || includeSpans.End() <= excludeSpans.Start())
break; // we found a match
moreInclude = includeSpans.Next(); // intersected: keep scanning
}
return moreInclude;
}
public virtual bool SkipTo(int target)
{
if (moreInclude)
// skip include
moreInclude = includeSpans.SkipTo(target);
if (!moreInclude)
return false;
if (moreExclude && includeSpans.Doc() > excludeSpans.Doc())
moreExclude = excludeSpans.SkipTo(includeSpans.Doc());
while (moreExclude && includeSpans.Doc() == excludeSpans.Doc() && excludeSpans.End() <= includeSpans.Start())
{
moreExclude = excludeSpans.Next(); // increment exclude
}
if (!moreExclude || includeSpans.Doc() != excludeSpans.Doc() || includeSpans.End() <= excludeSpans.Start())
return true; // we found a match
return Next(); // scan to next match
}
public virtual int Doc()
{
return includeSpans.Doc();
}
public virtual int Start()
{
return includeSpans.Start();
}
public virtual int End()
{
return includeSpans.End();
}
public override System.String ToString()
{
return "spans(" + Enclosing_Instance.ToString() + ")";
}
}
private SpanQuery include;
private SpanQuery exclude;
/// <summary>Construct a SpanNotQuery matching spans from <code>include</code> which
/// have no overlap with spans from <code>exclude</code>.
/// </summary>
public SpanNotQuery(SpanQuery include, SpanQuery exclude)
{
this.include = include;
this.exclude = exclude;
if (!include.GetField().Equals(exclude.GetField()))
throw new System.ArgumentException("Clauses must have same field.");
}
/// <summary>Return the SpanQuery whose matches are filtered. </summary>
public virtual SpanQuery GetInclude()
{
return include;
}
/// <summary>Return the SpanQuery whose matches must not overlap those returned. </summary>
public virtual SpanQuery GetExclude()
{
return exclude;
}
public override System.String GetField()
{
return include.GetField();
}
public override System.Collections.ICollection GetTerms()
{
return include.GetTerms();
}
public override System.String ToString(System.String field)
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
buffer.Append("spanNot(");
buffer.Append(include.ToString(field));
buffer.Append(", ");
buffer.Append(exclude.ToString(field));
buffer.Append(")");
buffer.Append(ToStringUtils.Boost(GetBoost()));
return buffer.ToString();
}
public override Spans GetSpans(IndexReader reader)
{
return new AnonymousClassSpans(reader, this);
}
public override Query Rewrite(IndexReader reader)
{
SpanNotQuery clone = null;
SpanQuery rewrittenInclude = (SpanQuery) include.Rewrite(reader);
if (rewrittenInclude != include)
{
clone = (SpanNotQuery) this.Clone();
clone.include = rewrittenInclude;
}
SpanQuery rewrittenExclude = (SpanQuery) exclude.Rewrite(reader);
if (rewrittenExclude != exclude)
{
if (clone == null)
clone = (SpanNotQuery) this.Clone();
clone.exclude = rewrittenExclude;
}
if (clone != null)
{
return clone; // some clauses rewrote
}
else
{
return this; // no clauses rewrote
}
}
}
}
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