/*
* 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 System;
using Lucene.Net.Analysis;
using Version = Lucene.Net.Util.Version;
namespace Lucene.Net.Analysis.Standard
{
/// Filters {@link StandardTokenizer} with {@link StandardFilter},
/// {@link LowerCaseFilter} and {@link StopFilter}, using a list of English stop
/// words.
///
///
///
/// You must specify the required {@link Version} compatibility when creating
/// StandardAnalyzer:
///
/// - As of 2.9, StopFilter preserves position increments
/// - As of 2.4, Tokens incorrectly identified as acronyms are corrected (see
/// LUCENE-1608
///
///
///
/// $Id: StandardAnalyzer.java 829134 2009-10-23 17:18:53Z mikemccand $
///
public class StandardAnalyzer : Analyzer
{
private System.Collections.Hashtable stopSet;
/// Specifies whether deprecated acronyms should be replaced with HOST type.
/// This is false by default to support backward compatibility.
///
///
/// this should be removed in the next release (3.0).
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
[Obsolete("this should be removed in the next release (3.0).")]
private bool replaceInvalidAcronym = defaultReplaceInvalidAcronym;
private static bool defaultReplaceInvalidAcronym;
private bool enableStopPositionIncrements;
// @deprecated
[Obsolete]
private bool useDefaultStopPositionIncrements;
///
/// true if new instances of StandardTokenizer will
/// replace mischaracterized acronyms
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
/// This will be removed (hardwired to true) in 3.0
///
[Obsolete("This will be removed (hardwired to true) in 3.0")]
public static bool GetDefaultReplaceInvalidAcronym()
{
return defaultReplaceInvalidAcronym;
}
///
/// Set to true to have new
/// instances of StandardTokenizer replace mischaracterized
/// acronyms by default. Set to false to preserve the
/// previous (before 2.4) buggy behavior. Alternatively,
/// set the system property
/// Lucene.Net.Analysis.Standard.StandardAnalyzer.replaceInvalidAcronym
/// to false.
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
/// This will be removed (hardwired to true) in 3.0
///
[Obsolete("This will be removed (hardwired to true) in 3.0")]
public static void SetDefaultReplaceInvalidAcronym(bool replaceInvalidAcronym)
{
defaultReplaceInvalidAcronym = replaceInvalidAcronym;
}
/// An array containing some common English words that are usually not
/// useful for searching.
///
/// Use {@link #STOP_WORDS_SET} instead
///
[Obsolete("Use STOP_WORDS_SET instead ")]
public static readonly System.String[] STOP_WORDS;
/// An unmodifiable set containing some common English words that are usually not
/// useful for searching.
///
public static readonly System.Collections.Hashtable STOP_WORDS_SET;
/// Builds an analyzer with the default stop words ({@link
/// #STOP_WORDS_SET}).
///
/// Use {@link #StandardAnalyzer(Version)} instead.
///
[Obsolete("Use StandardAnalyzer(Version) instead")]
public StandardAnalyzer():this(Version.LUCENE_24, STOP_WORDS_SET)
{
}
/// Builds an analyzer with the default stop words ({@link
/// #STOP_WORDS}).
///
/// Lucene version to match See {@link
/// above}
///
public StandardAnalyzer(Version matchVersion):this(matchVersion, STOP_WORDS_SET)
{
}
/// Builds an analyzer with the given stop words.
/// Use {@link #StandardAnalyzer(Version, Set)}
/// instead
///
[Obsolete("Use StandardAnalyzer(Version, Set) instead")]
public StandardAnalyzer(System.Collections.Hashtable stopWords):this(Version.LUCENE_24, stopWords)
{
}
/// Builds an analyzer with the given stop words.
/// Lucene version to match See {@link
/// above}
///
/// stop words
///
public StandardAnalyzer(Version matchVersion, System.Collections.Hashtable stopWords)
{
stopSet = stopWords;
Init(matchVersion);
}
/// Builds an analyzer with the given stop words.
/// Use {@link #StandardAnalyzer(Version, Set)} instead
///
[Obsolete("Use StandardAnalyzer(Version, Set) instead")]
public StandardAnalyzer(System.String[] stopWords):this(Version.LUCENE_24, StopFilter.MakeStopSet(stopWords))
{
}
/// Builds an analyzer with the stop words from the given file.
///
///
/// Use {@link #StandardAnalyzer(Version, File)}
/// instead
///
[Obsolete("Use StandardAnalyzer(Version, File) instead")]
public StandardAnalyzer(System.IO.FileInfo stopwords):this(Version.LUCENE_24, stopwords)
{
}
/// Builds an analyzer with the stop words from the given file.
///
///
/// Lucene version to match See {@link
/// above}
///
/// File to read stop words from
///
public StandardAnalyzer(Version matchVersion, System.IO.FileInfo stopwords)
{
stopSet = WordlistLoader.GetWordSet(stopwords);
Init(matchVersion);
}
/// Builds an analyzer with the stop words from the given reader.
///
///
/// Use {@link #StandardAnalyzer(Version, Reader)}
/// instead
///
[Obsolete("Use StandardAnalyzer(Version, Reader) instead")]
public StandardAnalyzer(System.IO.TextReader stopwords):this(Version.LUCENE_24, stopwords)
{
}
/// Builds an analyzer with the stop words from the given reader.
///
///
/// Lucene version to match See {@link
/// above}
///
/// Reader to read stop words from
///
public StandardAnalyzer(Version matchVersion, System.IO.TextReader stopwords)
{
stopSet = WordlistLoader.GetWordSet(stopwords);
Init(matchVersion);
}
///
/// Set to true if this analyzer should replace mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
///
/// Remove in 3.X and make true the only valid value
///
[Obsolete("Remove in 3.X and make true the only valid value")]
public StandardAnalyzer(bool replaceInvalidAcronym):this(Version.LUCENE_24, STOP_WORDS_SET)
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
useDefaultStopPositionIncrements = true;
}
/// The stopwords to use
///
/// Set to true if this analyzer should replace mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
///
/// Remove in 3.X and make true the only valid value
///
[Obsolete("Remove in 3.X and make true the only valid value")]
public StandardAnalyzer(System.IO.TextReader stopwords, bool replaceInvalidAcronym):this(Version.LUCENE_24, stopwords)
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
}
/// The stopwords to use
///
/// Set to true if this analyzer should replace mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
///
/// Remove in 3.X and make true the only valid value
///
[Obsolete("Remove in 3.X and make true the only valid value")]
public StandardAnalyzer(System.IO.FileInfo stopwords, bool replaceInvalidAcronym):this(Version.LUCENE_24, stopwords)
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
}
///
/// The stopwords to use
///
/// Set to true if this analyzer should replace mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
///
/// Remove in 3.X and make true the only valid value
///
[Obsolete("Remove in 3.X and make true the only valid value")]
public StandardAnalyzer(System.String[] stopwords, bool replaceInvalidAcronym):this(Version.LUCENE_24, StopFilter.MakeStopSet(stopwords))
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
}
/// The stopwords to use
///
/// Set to true if this analyzer should replace mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
///
/// Remove in 3.X and make true the only valid value
///
[Obsolete("Remove in 3.X and make true the only valid value")]
public StandardAnalyzer(System.Collections.Hashtable stopwords, bool replaceInvalidAcronym):this(Version.LUCENE_24, stopwords)
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
}
private void Init(Version matchVersion)
{
SetOverridesTokenStreamMethod(typeof(StandardAnalyzer));
if (matchVersion.OnOrAfter(Version.LUCENE_29))
{
enableStopPositionIncrements = true;
}
else
{
useDefaultStopPositionIncrements = true;
}
if (matchVersion.OnOrAfter(Version.LUCENE_24))
{
replaceInvalidAcronym = defaultReplaceInvalidAcronym;
}
else
{
replaceInvalidAcronym = false;
}
}
/// Constructs a {@link StandardTokenizer} filtered by a {@link
/// StandardFilter}, a {@link LowerCaseFilter} and a {@link StopFilter}.
///
public override TokenStream TokenStream(System.String fieldName, System.IO.TextReader reader)
{
StandardTokenizer tokenStream = new StandardTokenizer(reader, replaceInvalidAcronym);
tokenStream.SetMaxTokenLength(maxTokenLength);
TokenStream result = new StandardFilter(tokenStream);
result = new LowerCaseFilter(result);
if (useDefaultStopPositionIncrements)
{
result = new StopFilter(result, stopSet);
}
else
{
result = new StopFilter(enableStopPositionIncrements, result, stopSet);
}
return result;
}
private sealed class SavedStreams
{
internal StandardTokenizer tokenStream;
internal TokenStream filteredTokenStream;
}
/// Default maximum allowed token length
public const int DEFAULT_MAX_TOKEN_LENGTH = 255;
private int maxTokenLength = DEFAULT_MAX_TOKEN_LENGTH;
/// Set maximum allowed token length. If a token is seen
/// that exceeds this length then it is discarded. This
/// setting only takes effect the next time tokenStream or
/// reusableTokenStream is called.
///
public virtual void SetMaxTokenLength(int length)
{
maxTokenLength = length;
}
///
///
public virtual int GetMaxTokenLength()
{
return maxTokenLength;
}
/// Use {@link #tokenStream} instead
///
[Obsolete("Use TokenStream instead")]
public override TokenStream ReusableTokenStream(System.String fieldName, System.IO.TextReader reader)
{
if (overridesTokenStreamMethod)
{
// LUCENE-1678: force fallback to tokenStream() if we
// have been subclassed and that subclass overrides
// tokenStream but not reusableTokenStream
return TokenStream(fieldName, reader);
}
SavedStreams streams = (SavedStreams) GetPreviousTokenStream();
if (streams == null)
{
streams = new SavedStreams();
SetPreviousTokenStream(streams);
streams.tokenStream = new StandardTokenizer(reader);
streams.filteredTokenStream = new StandardFilter(streams.tokenStream);
streams.filteredTokenStream = new LowerCaseFilter(streams.filteredTokenStream);
if (useDefaultStopPositionIncrements)
{
streams.filteredTokenStream = new StopFilter(streams.filteredTokenStream, stopSet);
}
else
{
streams.filteredTokenStream = new StopFilter(enableStopPositionIncrements, streams.filteredTokenStream, stopSet);
}
}
else
{
streams.tokenStream.Reset(reader);
}
streams.tokenStream.SetMaxTokenLength(maxTokenLength);
streams.tokenStream.SetReplaceInvalidAcronym(replaceInvalidAcronym);
return streams.filteredTokenStream;
}
///
/// true if this Analyzer is replacing mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
/// This will be removed (hardwired to true) in 3.0
///
[Obsolete("This will be removed (hardwired to true) in 3.0")]
public virtual bool IsReplaceInvalidAcronym()
{
return replaceInvalidAcronym;
}
///
/// Set to true if this Analyzer is replacing mischaracterized acronyms in the StandardTokenizer
///
/// See https://issues.apache.org/jira/browse/LUCENE-1068
///
/// This will be removed (hardwired to true) in 3.0
///
[Obsolete("This will be removed (hardwired to true) in 3.0")]
public virtual void SetReplaceInvalidAcronym(bool replaceInvalidAcronym)
{
this.replaceInvalidAcronym = replaceInvalidAcronym;
}
static StandardAnalyzer()
{
// Default to true (fixed the bug), unless the system prop is set
{
System.String v = SupportClass.AppSettings.Get("Lucene.Net.Analysis.Standard.StandardAnalyzer.replaceInvalidAcronym", "true");
if (v == null || v.Equals("true"))
defaultReplaceInvalidAcronym = true;
else
defaultReplaceInvalidAcronym = false;
}
STOP_WORDS = StopAnalyzer.ENGLISH_STOP_WORDS;
STOP_WORDS_SET = StopAnalyzer.ENGLISH_STOP_WORDS_SET;
}
}
}