/*
* 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 Lucene.Net.Analysis.Tokenattributes;
namespace Lucene.Net.Analysis.Payloads
{
///
/// Characters before the delimiter are the "token", those after are the payload.
///
/// For example, if the delimiter is '|', then for the string "foo|bar", foo is the token
/// and "bar" is a payload.
///
/// Note, you can also include a {@link org.apache.lucene.analysis.payloads.PayloadEncoder} to convert the
/// payload in an appropriate way (from characters to bytes).
///
/// Note make sure your Tokenizer doesn't split on the delimiter, or this won't work
///
///
public sealed class DelimitedPayloadTokenFilter : TokenFilter
{
public static readonly char DEFAULT_DELIMITER = '|';
internal char delimiter = DEFAULT_DELIMITER;
internal ITermAttribute termAtt;
internal IPayloadAttribute payAtt;
internal PayloadEncoder encoder;
///
/// Construct a token stream filtering the given input.
///
internal DelimitedPayloadTokenFilter(TokenStream input)
: this(input, DEFAULT_DELIMITER, new IdentityEncoder())
{
}
public DelimitedPayloadTokenFilter(TokenStream input, char delimiter, PayloadEncoder encoder)
: base(input)
{
termAtt = AddAttribute();
payAtt = AddAttribute();
this.delimiter = delimiter;
this.encoder = encoder;
}
public override bool IncrementToken()
{
bool result = false;
if (input.IncrementToken())
{
char[] buffer = termAtt.TermBuffer();
int length = termAtt.TermLength();
//look for the delimiter
bool seen = false;
for (int i = 0; i < length; i++)
{
if (buffer[i] == delimiter)
{
termAtt.SetTermBuffer(buffer, 0, i);
payAtt.Payload = encoder.Encode(buffer, i + 1, (length - (i + 1)));
seen = true;
break;//at this point, we know the whole piece, so we can exit. If we don't see the delimiter, then the termAtt is the same
}
}
if (seen == false)
{
//no delimiter
payAtt.Payload = null;
}
result = true;
}
return result;
}
}
}