/*
* 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>Matches spans near the beginning of a field. </summary>
[Serializable]
public class SpanFirstQuery : SpanQuery
{
private class AnonymousClassSpans : Spans
{
public AnonymousClassSpans(Lucene.Net.Index.IndexReader reader, SpanFirstQuery enclosingInstance)
{
InitBlock(reader, enclosingInstance);
}
private void InitBlock(Lucene.Net.Index.IndexReader reader, SpanFirstQuery enclosingInstance)
{
this.reader = reader;
this.enclosingInstance = enclosingInstance;
spans = Enclosing_Instance.match.GetSpans(reader);
}
private Lucene.Net.Index.IndexReader reader;
private SpanFirstQuery enclosingInstance;
public SpanFirstQuery Enclosing_Instance
{
get
{
return enclosingInstance;
}
}
private Spans spans;
public virtual bool Next()
{
while (spans.Next())
{
// scan to next match
if (End() <= Enclosing_Instance.end)
return true;
}
return false;
}
public virtual bool SkipTo(int target)
{
if (!spans.SkipTo(target))
return false;
if (spans.End() <= Enclosing_Instance.end)
// there is a match
return true;
return Next(); // scan to next match
}
public virtual int Doc()
{
return spans.Doc();
}
public virtual int Start()
{
return spans.Start();
}
public virtual int End()
{
return spans.End();
}
public override System.String ToString()
{
return "spans(" + Enclosing_Instance.ToString() + ")";
}
}
private SpanQuery match;
private int end;
/// <summary>Construct a SpanFirstQuery matching spans in <code>match</code> whose end
/// position is less than or equal to <code>end</code>.
/// </summary>
public SpanFirstQuery(SpanQuery match, int end)
{
this.match = match;
this.end = end;
}
/// <summary>Return the SpanQuery whose matches are filtered. </summary>
public virtual SpanQuery GetMatch()
{
return match;
}
/// <summary>Return the maximum end position permitted in a match. </summary>
public virtual int GetEnd()
{
return end;
}
public override System.String GetField()
{
return match.GetField();
}
public override System.Collections.ICollection GetTerms()
{
return match.GetTerms();
}
public override System.String ToString(System.String field)
{
System.Text.StringBuilder buffer = new System.Text.StringBuilder();
buffer.Append("spanFirst(");
buffer.Append(match.ToString(field));
buffer.Append(", ");
buffer.Append(end);
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)
{
SpanFirstQuery clone = null;
SpanQuery rewritten = (SpanQuery) match.Rewrite(reader);
if (rewritten != match)
{
clone = (SpanFirstQuery) this.Clone();
clone.match = rewritten;
}
if (clone != null)
{
return clone; // some clauses rewrote
}
else
{
return this; // no clauses rewrote
}
}
}
}
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