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CannedTokenStream.cs
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CannedTokenStream.cs
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using Lucene.Net.Analysis.TokenAttributes;
namespace Lucene.Net.Analysis
{
/*
* 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>
/// <see cref="TokenStream"/> from a canned list of <see cref="Token"/>s.
/// </summary>
public sealed class CannedTokenStream : TokenStream
{
private readonly Token[] tokens;
private int upto = 0;
private readonly ICharTermAttribute termAtt;
private readonly IPositionIncrementAttribute posIncrAtt;
private readonly IPositionLengthAttribute posLengthAtt;
private readonly IOffsetAttribute offsetAtt;
private readonly IPayloadAttribute payloadAtt;
private readonly int finalOffset;
private readonly int finalPosInc;
public CannedTokenStream(params Token[] tokens)
: this(0, 0, tokens)
{ }
/// <summary>
/// If you want trailing holes, pass a non-zero
/// <paramref name="finalPosInc"/>.
/// </summary>
public CannedTokenStream(int finalPosInc, int finalOffset, params Token[] tokens)
{
termAtt = AddAttribute<ICharTermAttribute>();
posIncrAtt = AddAttribute<IPositionIncrementAttribute>();
posLengthAtt = AddAttribute<IPositionLengthAttribute>();
offsetAtt = AddAttribute<IOffsetAttribute>();
payloadAtt = AddAttribute<IPayloadAttribute>();
this.tokens = tokens;
this.finalOffset = finalOffset;
this.finalPosInc = finalPosInc;
}
public override void End()
{
base.End();
posIncrAtt.PositionIncrement = finalPosInc;
offsetAtt.SetOffset(finalOffset, finalOffset);
}
public override bool IncrementToken()
{
if (upto < tokens.Length)
{
Token token = tokens[upto++];
// TODO: can we just capture/restoreState so
// we get all attrs...?
ClearAttributes();
termAtt.SetEmpty();
termAtt.Append(token.ToString());
posIncrAtt.PositionIncrement = token.PositionIncrement;
posLengthAtt.PositionLength = token.PositionLength;
offsetAtt.SetOffset(token.StartOffset, token.EndOffset);
payloadAtt.Payload = token.Payload;
return true;
}
else
{
return false;
}
}
}
}