Lucene 1.9 改进特性列表

1.9 RC1

注：lucene2.0发布版本并不是100%的和1.4.3版兼容。也就是说在你用2.0版本的Lucene开发包替换原来的1.4.3版本时，应该让你的应用程序首先和1.9的兼容。

使用前提：

1. 编译和使用Lucene需要 Java1.4 或以上版本。

Lucene 1.9 在运行时的变化：

1. 模糊搜索 FuzzyQuery 不再抛出 TooManyClauses 异常。当 FuzzyQuery 扩展多于 BooleanQuery.maxClauseCount 时，只有最相关的term会被重新写入query,因此避免了异常的抛出。 (Christoph)

2. 把系统属性 "org.apache.lucene.lockdir" 改为 "org.apache.lucene.lockDir"。(Bernhard)

3. RangeQueries 和 FuzzyQueries 默认被转换成小写。 (as it has been the case for PrefixQueries and WildcardQueries before).使用 setLowercaseExpandedTerms(false) 来禁止大小写自动转换的行为；同样也影响 PrefixQueries 和 WildcardQueries。(Daniel Naber)

4. 在使用 MultiSearcher 的时候文档频率也可以正确计算，全局性的计算各个 subsearchers 和 indices 中。以前计算的时候只是 locally 的，每个 index 的计算是分开的，这样引发的一个问题是：在多个indices中rank 是不相等的。
(Chuck Williams, Wolf Siberski via Otis, bug #31841)

5. 在打开 IndexWriter 使用 create=true 参数，Lucene 现在只是删除index目录中属于Lucene自己的文件。( 判断文件名后缀的方式 )。原来是删除整个目录中的所有文件。(Daniel Naber and Bernhard Messer, bug #34695)

6. IndexReader 的版本，可以通过 getCurrentVersion() 和 getVersion() 返回。以前如果是新的indexes 那么返回的是0 。现在则用系统的毫秒数来初始化。 (Bernhard Messer via Daniel Naber)

7. 一些默认的初始化值不再允许通过 system properties 来设置。相反在 IndexWriter 中新增了相关的 set/get 方法来设置相关属性。主要包括以下属性：
    在 IndexWriter 的 getter/setter 方法中:
      org.apache.lucene.writeLockTimeout, org.apache.lucene.commitLockTimeout,
      org.apache.lucene.minMergeDocs, org.apache.lucene.maxMergeDocs,
      org.apache.lucene.maxFieldLength, org.apache.lucene.termIndexInterval,
      org.apache.lucene.mergeFactor,
    还有 BooleanQuery 的 getter/setter 方法:
      org.apache.lucene.maxClauseCount
    还有 FSDirectory 的 getter/setter 方法：
      disableLuceneLocks
    (Daniel Naber)

8. 修改了 FieldCacheImpl 方法使用用户提供的 IntParser 和 FloatParser,来替代使用 Integer 和 Float 的相关方法。
(Yonik Seeley via Otis Gospodnetic)

9. 高级搜索返回的 TopDocs 和 TopFieldDocs 不再规范scores。
(Luc Vanlerberghe via Yonik Seeley, LUCENE-469)

1.9 的新特性：

1. 增加了对压缩字段存储的支持。(patch #31149)
(Bernhard Messer via Christoph)

2. 增加了对压缩字段存储的支持。(patch #29370)
(Bernhard Messer via Christoph)

3. 在 term vectors 中增加了位置和偏移信息。(Grant Ingersoll & Christoph)

4. 增加了一个新的 DateTools 。允许用户格式化日期到一种更可读的格式，以便于更好的适应索引。DateTools 不像 DateFields 类，它允许日期指定到1970年以前，但必须使用指定的日期格式。这样，在RangeQuerys中使用就更加有效率了。 (Daniel Naber)

5. QueryParser 现在可以正确的和Analyzers 一起工作了，即可以在一个位置返回多个 Token 。比如：查询： “+fast + car”如果 Analyzer 在同一位置返回 car 和 automobile ，那么上面的查询将被解析成：”+fast +(car automobile)”。 (Pierrick Brihaye, Daniel Naber)

6. 允许unbuffered的目录实现。（e.g.,using mmap）。
InputStream 被新类 IndexInput 替换， BufferedIndexInput 和 OutputStream 则被 IndexOutput 和 BufferedIndexOutput。 InputStream 和 OutputStream 已经被废弃了。FSDirectory 现在是一个子类了。(cutting)

7. 增加了原生 Directory 和 TermDocs 的实现，可以工作在 GCJ 下。GCJ的版本需要 3.4.0 以上。可以使用 ant gcj 来运行例子程序。(cutting)

8. 增加了 MmapDirectory 类，它使用 nio to mmap 输入文件。现在MmapDirectory 比FSDirectory 要慢些。但他对每个查询term 使用更少的内存。(cutting & Paul Elschot)

9. 增加 javadocs-internal 到 build.xml ? bug #30360

10. 增加了 RangeFileter ,比 DateFilter 更加通用，实用。
(Chris M Hostetter via Erik)

11. 增加了 NumberTools ，一个用来索引数字字段的工具类。 (adapted from code contributed by Matt Quail; committed by Erik)

12. 增加了 public static IndexReader.main(String[] args) 方法。
IndexReader 现在可以直接在命令行方式下使用，用来列出或者从现存的索引中抽取单独的文件出来。
(adapted from code contributed by Garrett Rooney; committed by Bernhard)

13. 增加 IndexWriter.setTermIndexInterval() 方法。 (Doug Cutting)

14. 增加 LucenePackage ,这些静态的 get() 方法返回 java.util.Package。调用者可以用它来获得 Lucene jar 中的版本信息。
(Doug Cutting via Otis)

15. 增加 Hits.iterator() 方法和相应的 HitIterator 和 Hit 对象。他提供了对 Hits对象标准的 java.util.Iterator 叠代操作。
每个iterator's next() 方法返回一个 Hit 对象。 (Jeremy Rayner via Erik)

16. 增加 ParallelReader，这个一种IndexReader 他合并多个单独的索引到一个单独的虚拟索引上。(Doug Cutting)

17. 增加对 FieldCache 的 IntParser ， FloatParser 接口, 这样任何格式的字段可以被以int 和float的形式缓存。
(Doug Cutting)

18. 新增类： org.apache.lucene.index.IndexModifier ，它合并了 IndexWriter 和 IndexReader，好处是我们可以增加和删除文档的时候不同担心 synchronisation/locking 的问题了。 (Daniel Naber)

19. Lucene 现在可以被用在一个没有签名的applet中了，Lucene’s 读取系统属性不会抛出 SecurityException 异常。
(Jon Schuster via Daniel Naber, bug #34359)

20. 增加了新类 MatchAllDocsQuery 用来匹配所有文档。
(John Wang via Daniel Naber, bug #34946)

21. 当索引太多的字段时，为了消减索引大小和内存消耗，提供了忽略规范化字段的功能。
见: Field.setOmitNorms() (Yonik Seeley, LUCENE-448)

22. 增加对 contrib/highlighter 的 NullFragmenter , 这对全文本加亮很有用。
(Erik Hatcher)

23. 增加了正则表达式的查询： RegexQuery 和 SpanRegexQuery。
(Erik Hatcher)

24. 增加 ConstantScoreQuery 类，它包装了一个 filter produces a score
equal to the query boost for every matching document.
(Yonik Seeley, LUCENE-383)

25. 增加了 ConstantScoreRangeQuery 类，为某个区间的每个文档提供一个不变的 score。这个类比普通的 RangeQuery 类的好处是它并不展开到 BooleanQuery ，因此也不存在区间最大term上限。 (Yonik Seeley, LUCENE-383)

26. 为BooleanQuery增加了最小的匹配短语。见：BooleanQuery.setMinimumNumberShouldMatch().
(Paul Elschot, Chris Hostetter via Yonik Seeley, LUCENE-395)

27. 增加了 DisjunctionMaxQuery 类，提供了针对某个短语的最大score。这一点对多字段的搜索非常有用。
(Luc Vanlerberghe via Yonik Seeley, LUCENE-323)

28. 新增类：ISOLatin1AccentFilter ,用 ISO Latin 1 字符集中的unaccented类字符替代 accented 类字符。 (Sven Duzont via Erik Hatcher)

29. 新增类：KeywordAnalyzer。"Tokenizes" 整个流作为一个单独的token。这个类对于邮政编码，序列号，和产品名称等比较有用。
(Erik Hatcher)

30. 把 LengthFilter 类从 contrib 放到了 core 代码里。从 stream 中去掉太长和太短的单词。 (David Spencer via Otis and Daniel)

31. 增加了 getPositionIncrementGap 方法到 Analyzer 中。这样用户自定义的 analyzer 可以在相同字段名的实例之间增加间隙 gaps，用来防止 phrase 和 span 查询超出边界。默认的 gap 是 0 。 (Erik Hatcher, with advice from Yonik)

32. StopFilter 增加了对处理stop words 的忽略大小写处理。 (Grant Ingersoll via Yonik, LUCENE-248)

33. 增加了 TopDocCollector 和 TopFieldDocCollector。用来简化实现hit 集合针对 top-scoring 和 top-sorting hits的处理。

API 的改变：

1. 几个方法和字段已经被废弃。在API 文档中包含了建议替换的内容。在这些建议中，这些不建议使用的方法和字段将会在Lucene2.0中被删除。(Daniel Naber)

2. Russian 和 German 的 analyzers 被移到了 contrib/analyzers 。同样 WordlistLoader 类也被放到了 org.apache.lucene.analysis.WordlistLoader 下 (Daniel Naber)

3. API 包含抛出 IOException 异常的声明，但是实际上不会抛出。 These declarations have been removed. If
your code tries to catch these exceptions you might need to remove
those catch clauses to avoid compile errors.(Daniel Naber)

4. 为BooleanClause 类的enum 标准参数增加序列化的参数类。 (Christoph)

5. 为 SpanQuery 的子类嵌套其他SpanQuery 增加了 rewrite方法。

Lucene 的源代码管理器也从cvs 换到了svn： http://svn.apache.org/repos/asf/lucene/java/trunk

Lucene Change Log $Id$ 1.9.1 Bug fixes 1. LUCENE-511: Fix a bug in the BufferedIndexOutput optimization introduced in 1.9-final. 1.9 final Note that this realease is mostly but not 100% source compatible with the previous release of Lucene (1.4.3). In other words, you should make sure your application compiles with this version of Lucene before you replace the old Lucene JAR with the new one. Many methods have been deprecated in anticipation of release 2.0, so deprecation warnings are to be expected when upgrading from 1.4.3 to 1.9. Bug fixes 1. The fix that made IndexWriter.setMaxBufferedDocs(1) work had negative effects on indexing performance and has thus been reverted. The argument for setMaxBufferedDocs(int) must now at least be 2, otherwise an exception is thrown. Optimizations 1. Optimized BufferedIndexOutput.writeBytes() to use System.arraycopy() in more cases, rather than copying byte-by-byte. (Lukas Zapletal via Cutting) 1.9 RC1 Requirements 1. To compile and use Lucene you now need Java 1.4 or later. Changes in runtime behavior 1. FuzzyQuery can no longer throw a TooManyClauses exception. If a FuzzyQuery expands to more than BooleanQuery.maxClauseCount terms only the BooleanQuery.maxClauseCount most similar terms go into the rewritten query and thus the exception is avoided. (Christoph) 2. Changed system property from "org.apache.lucene.lockdir" to "org.apache.lucene.lockDir", so that its casing follows the existing pattern used in other Lucene system properties. (Bernhard) 3. The terms of RangeQueries and FuzzyQueries are now converted to lowercase by default (as it has been the case for PrefixQueries and WildcardQueries before). Use setLowercaseExpandedTerms(false) to disable that behavior but note that this also affects PrefixQueries and WildcardQueries. (Daniel Naber) 4. Document frequency that is computed when MultiSearcher is used is now computed correctly and "globally" across subsearchers and indices, while before it used to be computed locally to each index, which caused ranking across multiple indices not to be equivalent. (Chuck Williams, Wolf Siberski via Otis, bug #31841) 5. When opening an IndexWriter with create=true, Lucene now only deletes its own files from the index directory (looking at the file name suffixes to decide if a file belongs to Lucene). The old behavior was to delete all files. (Daniel Naber and Bernhard Messer, bug #34695) 6. The version of an IndexReader, as returned by getCurrentVersion() and getVersion() doesn't start at 0 anymore for new indexes. Instead, it is now initialized by the system time in milliseconds. (Bernhard Messer via Daniel Naber) 7. Several default values cannot be set via system properties anymore, as this has been considered inappropriate for a library like Lucene. For most properties there are set/get methods available in IndexWriter which you should use instead. This affects the following properties: See IndexWriter for getter/setter methods: org.apache.lucene.writeLockTimeout, org.apache.lucene.commitLockTimeout, org.apache.lucene.minMergeDocs, org.apache.lucene.maxMergeDocs, org.apache.lucene.maxFieldLength, org.apache.lucene.termIndexInterval, org.apache.lucene.mergeFactor, See BooleanQuery for getter/setter methods: org.apache.lucene.maxClauseCount See FSDirectory for getter/setter methods: disableLuceneLocks (Daniel Naber) 8. Fixed FieldCacheImpl to use user-provided IntParser and FloatParser, instead of using Integer and Float classes for parsing. (Yonik Seeley via Otis Gospodnetic) 9. Expert level search routines returning TopDocs and TopFieldDocs no longer normalize scores. This also fixes bugs related to MultiSearchers and score sorting/normalization. (Luc Vanlerberghe via Yonik Seeley, LUCENE-469) New features 1. Added support for stored compressed fields (patch #31149) (Bernhard Messer via Christoph) 2. Added support for binary stored fields (patch #29370) (Drew Farris and Bernhard Messer via Christoph) 3. Added support for position and offset information in term vectors (patch #18927). (Grant Ingersoll &amp; Christoph) 4. A new class DateTools has been added. It allows you to format dates in a readable format adequate for indexing. Unlike the existing DateField class DateTools can cope with dates before 1970 and it forces you to specify the desired date resolution (e.g. month, day, second, ...) which can make RangeQuerys on those fields more efficient. (Daniel Naber) 5. QueryParser now correctly works with Analyzers that can return more than one token per position. For example, a query "+fast +car" would be parsed as "+fast +(car automobile)" if the Analyzer returns "car" and "automobile" at the same position whenever it finds "car" (Patch #23307). (Pierrick Brihaye, Daniel Naber) 6. Permit unbuffered Directory implementations (e.g., using mmap). InputStream is replaced by the new classes IndexInput and BufferedIndexInput. OutputStream is replaced by the new classes IndexOutput and BufferedIndexOutput. InputStream and OutputStream are now deprecated and FSDirectory is now subclassable. (cutting) 7. Add native Directory and TermDocs implementations that work under GCJ. These require GCC 3.4.0 or later and have only been tested on Linux. Use 'ant gcj' to build demo applications. (cutting) 8. Add MMapDirectory, which uses nio to mmap input files. This is still somewhat slower than FSDirectory. However it uses less memory per query term, since a new buffer is not allocated per term, which may help applications which use, e.g., wildcard queries. It may also someday be faster. (cutting &amp; Paul Elschot) 9. Added javadocs-internal to build.xml - bug #30360 (Paul Elschot via Otis) 10. Added RangeFilter, a more generically useful filter than DateFilter. (Chris M Hostetter via Erik) 11. Added NumberTools, a utility class indexing numeric fields. (adapted from code contributed by Matt Quail; committed by Erik) 12. Added public static IndexReader.main(String[] args) method. IndexReader can now be used directly at command line level to list and optionally extract the individual files from an existing compound index file. (adapted from code contributed by Garrett Rooney; committed by Bernhard) 13. Add IndexWriter.setTermIndexInterval() method. See javadocs. (Doug Cutting) 14. Added LucenePackage, whose static get() method returns java.util.Package, which lets the caller get the Lucene version information specified in the Lucene Jar. (Doug Cutting via Otis) 15. Added Hits.iterator() method and corresponding HitIterator and Hit objects. This provides standard java.util.Iterator iteration over Hits. Each call to the iterator's next() method returns a Hit object. (Jeremy Rayner via Erik) 16. Add ParallelReader, an IndexReader that combines separate indexes over different fields into a single virtual index. (Doug Cutting) 17. Add IntParser and FloatParser interfaces to FieldCache, so that fields in arbitrarily formats can be cached as ints and floats. (Doug Cutting) 18. Added class org.apache.lucene.index.IndexModifier which combines IndexWriter and IndexReader, so you can add and delete documents without worrying about synchronisation/locking issues. (Daniel Naber) 19. Lucene can now be used inside an unsigned applet, as Lucene's access to system properties will not cause a SecurityException anymore. (Jon Schuster via Daniel Naber, bug #34359) 20. Added a new class MatchAllDocsQuery that matches all documents. (John Wang via Daniel Naber, bug #34946) 21. Added ability to omit norms on a per field basis to decrease index size and memory consumption when there are many indexed fields. See Field.setOmitNorms() (Yonik Seeley, LUCENE-448) 22. Added NullFragmenter to contrib/highlighter, which is useful for highlighting entire documents or fields. (Erik Hatcher) 23. Added regular expression queries, RegexQuery and SpanRegexQuery. Note the same term enumeration caveats apply with these queries as apply to WildcardQuery and other term expanding queries. These two new queries are not currently supported via QueryParser. (Erik Hatcher) 24. Added ConstantScoreQuery which wraps a filter and produces a score equal to the query boost for every matching document. (Yonik Seeley, LUCENE-383) 25. Added ConstantScoreRangeQuery which produces a constant score for every document in the range. One advantage over a normal RangeQuery is that it doesn't expand to a BooleanQuery and thus doesn't have a maximum number of terms the range can cover. Both endpoints may also be open. (Yonik Seeley, LUCENE-383) 26. Added ability to specify a minimum number of optional clauses that must match in a BooleanQuery. See BooleanQuery.setMinimumNumberShouldMatch(). (Paul Elschot, Chris Hostetter via Yonik Seeley, LUCENE-395) 27. Added DisjunctionMaxQuery which provides the maximum score across it's clauses. It's very useful for searching across multiple fields. (Chuck Williams via Yonik Seeley, LUCENE-323) 28. New class ISOLatin1AccentFilter that replaces accented characters in the ISO Latin 1 character set by their unaccented equivalent. (Sven Duzont via Erik Hatcher) 29. New class KeywordAnalyzer. "Tokenizes" the entire stream as a single token. This is useful for data like zip codes, ids, and some product names. (Erik Hatcher) 30. Copied LengthFilter from contrib area to core. Removes words that are too long and too short from the stream. (David Spencer via Otis and Daniel) 31. Added getPositionIncrementGap(String fieldName) to Analyzer. This allows custom analyzers to put gaps between Field instances with the same field name, preventing phrase or span queries crossing these boundaries. The default implementation issues a gap of 0, allowing the default token position increment of 1 to put the next field's first token into a successive position. (Erik Hatcher, with advice from Yonik) 32. StopFilter can now ignore case when checking for stop words. (Grant Ingersoll via Yonik, LUCENE-248) 33. Add TopDocCollector and TopFieldDocCollector. These simplify the implementation of hit collectors that collect only the top-scoring or top-sorting hits. API Changes 1. Several methods and fields have been deprecated. The API documentation contains information about the recommended replacements. It is planned that most of the deprecated methods and fields will be removed in Lucene 2.0. (Daniel Naber) 2. The Russian and the German analyzers have been moved to contrib/analyzers. Also, the WordlistLoader class has been moved one level up in the hierarchy and is now org.apache.lucene.analysis.WordlistLoader (Daniel Naber) 3. The API contained methods that declared to throw an IOException but that never did this. These declarations have been removed. If your code tries to catch these exceptions you might need to remove those catch clauses to avoid compile errors. (Daniel Naber) 4. Add a serializable Parameter Class to standardize parameter enum classes in BooleanClause and Field. (Christoph) 5. Added rewrite methods to all SpanQuery subclasses that nest other SpanQuerys. This allows custom SpanQuery subclasses that rewrite (for term expansion, for example) to nest within the built-in SpanQuery classes successfully. Bug fixes 1. The JSP demo page (src/jsp/results.jsp) now properly closes the IndexSearcher it opens. (Daniel Naber) 2. Fixed a bug in IndexWriter.addIndexes(IndexReader[] readers) that prevented deletion of obsolete segments. (Christoph Goller) 3. Fix in FieldInfos to avoid the return of an extra blank field in IndexReader.getFieldNames() (Patch #19058). (Mark Harwood via Bernhard) 4. Some combinations of BooleanQuery and MultiPhraseQuery (formerly PhrasePrefixQuery) could provoke UnsupportedOperationException (bug #33161). (Rhett Sutphin via Daniel Naber) 5. Small bug in skipTo of ConjunctionScorer that caused NullPointerException if skipTo() was called without prior call to next() fixed. (Christoph) 6. Disable Similiarty.coord() in the scoring of most automatically generated boolean queries. The coord() score factor is appropriate when clauses are independently specified by a user, but is usually not appropriate when clauses are generated automatically, e.g., by a fuzzy, wildcard or range query. Matches on such automatically generated queries are no longer penalized for not matching all terms. (Doug Cutting, Patch #33472) 7. Getting a lock file with Lock.obtain(long) was supposed to wait for a given amount of milliseconds, but this didn't work. (John Wang via Daniel Naber, Bug #33799) 8. Fix FSDirectory.createOutput() to always create new files. Previously, existing files were overwritten, and an index could be corrupted when the old version of a file was longer than the new. Now any existing file is first removed. (Doug Cutting) 9. Fix BooleanQuery containing nested SpanTermQuery's, which previously could return an incorrect number of hits. (Reece Wilton via Erik Hatcher, Bug #35157) 10. Fix NullPointerException that could occur with a MultiPhraseQuery inside a BooleanQuery. (Hans Hjelm and Scotty Allen via Daniel Naber, Bug #35626) 11. Fixed SnowballFilter to pass through the position increment from the original token. (Yonik Seeley via Erik Hatcher, LUCENE-437) 12. Added Unicode range of Korean characters to StandardTokenizer, grouping contiguous characters into a token rather than one token per character. This change also changes the token type to "<cj>" for Chinese and Japanese character tokens (previously it was "<cjk>"). (Cheolgoo Kang via Otis and Erik, LUCENE-444 and LUCENE-461) 13. FieldsReader now looks at FieldInfo.storeOffsetWithTermVector and FieldInfo.storePositionWithTermVector and creates the Field with correct TermVector parameter. (Frank Steinmann via Bernhard, LUCENE-455) 14. Fixed WildcardQuery to prevent "cat" matching "ca??". (Xiaozheng Ma via Bernhard, LUCENE-306) 15. Fixed a bug where MultiSearcher and ParallelMultiSearcher could change the sort order when sorting by string for documents without a value for the sort field. (Luc Vanlerberghe via Yonik, LUCENE-453) 16. Fixed a sorting problem with MultiSearchers that can lead to missing or duplicate docs due to equal docs sorting in an arbitrary order. (Yonik Seeley, LUCENE-456) 17. A single hit using the expert level sorted search methods resulted in the score not being normalized. (Yonik Seeley, LUCENE-462) 18. Fixed inefficient memory usage when loading an index into RAMDirectory. (Volodymyr Bychkoviak via Bernhard, LUCENE-475) 19. Corrected term offsets returned by ChineseTokenizer. (Ray Tsang via Erik Hatcher, LUCENE-324) 20. Fixed MultiReader.undeleteAll() to correctly update numDocs. (Robert Kirchgessner via Doug Cutting, LUCENE-479) 21. Race condition in IndexReader.getCurrentVersion() and isCurrent() fixed by aquiring the commit lock. (Luc Vanlerberghe via Yonik Seeley, LUCENE-481) 22. IndexWriter.setMaxBufferedDocs(1) didn't have the expected effect, this has now been fixed. (Daniel Naber) 23. Fixed QueryParser when called with a date in local form like "[1/16/2000 TO 1/18/2000]". This query did not include the documents of 1/18/2000, i.e. the last day was not included. (Daniel Naber) 24. Removed sorting constraint that threw an exception if there were not yet any values for the sort field (Yonik Seeley, LUCENE-374) Optimizations 1. Disk usage (peak requirements during indexing and optimization) in case of compound file format has been improved. (Bernhard, Dmitry, and Christoph) 2. Optimize the performance of certain uses of BooleanScorer, TermScorer and IndexSearcher. In particular, a BooleanQuery composed of TermQuery, with not all terms required, that returns a TopDocs (e.g., through a Hits with no Sort specified) runs much faster. (cutting) 3. Removed synchronization from reading of term vectors with an IndexReader (Patch #30736). (Bernhard Messer via Christoph) 4. Optimize term-dictionary lookup to allocate far fewer terms when scanning for the matching term. This speeds searches involving low-frequency terms, where the cost of dictionary lookup can be significant. (cutting) 5. Optimize fuzzy queries so the standard fuzzy queries with a prefix of 0 now run 20-50% faster (Patch #31882). (Jonathan Hager via Daniel Naber) 6. A Version of BooleanScorer (BooleanScorer2) added that delivers documents in increasing order and implements skipTo. For queries with required or forbidden clauses it may be faster than the old BooleanScorer, for BooleanQueries consisting only of optional clauses it is probably slower. The new BooleanScorer is now the default. (Patch 31785 by Paul Elschot via Christoph) 7. Use uncached access to norms when merging to reduce RAM usage. (Bug #32847). (Doug Cutting) 8. Don't read term index when random-access is not required. This reduces time to open IndexReaders and they use less memory when random access is not required, e.g., when merging segments. The term index is now read into memory lazily at the first random-access. (Doug Cutting) 9. Optimize IndexWriter.addIndexes(Directory[]) when the number of added indexes is larger than mergeFactor. Previously this could result in quadratic performance. Now performance is n log(n). (Doug Cutting) 10. Speed up the creation of TermEnum for indicies with multiple segments and deleted documents, and thus speed up PrefixQuery, RangeQuery, WildcardQuery, FuzzyQuery, RangeFilter, DateFilter, and sorting the first time on a field. (Yonik Seeley, LUCENE-454) 11. Optimized and generalized 32 bit floating point to byte (custom 8 bit floating point) conversions. Increased the speed of Similarity.encodeNorm() anywhere from 10% to 250%, depending on the JVM. (Yonik Seeley, LUCENE-467) Infrastructure 1. Lucene's source code repository has converted from CVS to Subversion. The new repository is at http://svn.apache.org/repos/asf/lucene/java/trunk 2. Lucene's issue tracker has migrated from Bugzilla to JIRA. Lucene's JIRA is at http://issues.apache.org/jira/browse/LUCENE The old issues are still available at http://issues.apache.org/bugzilla/show_bug.cgi?id=xxxx (use the bug number instead of xxxx) 1.4.3 1. The JSP demo page (src/jsp/results.jsp) now properly escapes error messages which might contain user input (e.g. error messages about query parsing). If you used that page as a starting point for your own code please make sure your code also properly escapes HTML characters from user input in order to avoid so-called cross site scripting attacks. (Daniel Naber) 2. QueryParser changes in 1.4.2 broke the QueryParser API. Now the old API is supported again. (Christoph) 1.4.2 1. Fixed bug #31241: Sorting could lead to incorrect results (documents missing, others duplicated) if the sort keys were not unique and there were more than 100 matches. (Daniel Naber) 2. Memory leak in Sort code (bug #31240) eliminated. (Rafal Krzewski via Christoph and Daniel) 3. FuzzyQuery now takes an additional parameter that specifies the minimum similarity that is required for a term to match the query. The QueryParser syntax for this is term~x, where x is a floating point number &gt;= 0 and &lt; 1 (a bigger number means that a higher similarity is required). Furthermore, a prefix can be specified for FuzzyQuerys so that only those terms are considered similar that start with this prefix. This can speed up FuzzyQuery greatly. (Daniel Naber, Christoph Goller) 4. PhraseQuery and PhrasePrefixQuery now allow the explicit specification of relative positions. (Christoph Goller) 5. QueryParser changes: Fix for ArrayIndexOutOfBoundsExceptions (patch #9110); some unused method parameters removed; The ability to specify a minimum similarity for FuzzyQuery has been added. (Christoph Goller) 6. IndexSearcher optimization: a new ScoreDoc is no longer allocated for every non-zero-scoring hit. This makes 'OR' queries that contain common terms substantially faster. (cutting) 1.4.1 1. Fixed a performance bug in hit sorting code, where values were not correctly cached. (Aviran via cutting) 2. Fixed errors in file format documentation. (Daniel Naber) 1.4 final 1. Added "an" to the list of stop words in StopAnalyzer, to complement the existing "a" there. Fix for bug 28960 (http://issues.apache.org/bugzilla/show_bug.cgi?id=28960). (Otis) 2. Added new class FieldCache to manage in-memory caches of field term values. (Tim Jones) 3. Added overloaded getFieldQuery method to QueryParser which accepts the slop factor specified for the phrase (or the default phrase slop for the QueryParser instance). This allows overriding methods to replace a PhraseQuery with a SpanNearQuery instead, keeping the proper slop factor. (Erik Hatcher) 4. Changed the encoding of GermanAnalyzer.java and GermanStemmer.java to UTF-8 and changed the build encoding to UTF-8, to make changed files compile. (Otis Gospodnetic) 5. Removed synchronization from term lookup under IndexReader methods termFreq(), termDocs() or termPositions() to improve multi-threaded performance. (cutting) 6. Fix a bug where obsolete segment files were not deleted on Win32. 1.4 RC3 1. Fixed several search bugs introduced by the skipTo() changes in release 1.4RC1. The index file format was changed a bit, so collections must be re-indexed to take advantage of the skipTo() optimizations. (Christoph Goller) 2. Added new Document methods, removeField() and removeFields(). (Christoph Goller) 3. Fixed inconsistencies with index closing. Indexes and directories are now only closed automatically by Lucene when Lucene opened them automatically. (Christoph Goller) 4. Added new class: FilteredQuery. (Tim Jones) 5. Added a new SortField type for custom comparators. (Tim Jones) 6. Lock obtain timed out message now displays the full path to the lock file. (Daniel Naber via Erik) 7. Fixed a bug in SpanNearQuery when ordered. (Paul Elschot via cutting) 8. Fixed so that FSDirectory's locks still work when the java.io.tmpdir system property is null. (cutting) 9. Changed FilteredTermEnum's constructor to take no parameters, as the parameters were ignored anyway (bug #28858) 1.4 RC2 1. GermanAnalyzer now throws an exception if the stopword file cannot be found (bug #27987). It now uses LowerCaseFilter (bug #18410) (Daniel Naber via Otis, Erik) 2. Fixed a few bugs in the file format documentation. (cutting) 1.4 RC1 1. Changed the format of the .tis file, so that: - it has a format version number, which makes it easier to back-compatibly change file formats in the future. - the term count is now stored as a long. This was the one aspect of the Lucene's file formats which limited index size. - a few internal index parameters are now stored in the index, so that they can (in theory) now be changed from index to index, although there is not yet an API to do so. These changes are back compatible. The new code can read old indexes. But old code will not be able read new indexes. (cutting) 2. Added an optimized implementation of TermDocs.skipTo(). A skip table is now stored for each term in the .frq file. This only adds a percent or two to overall index size, but can substantially speedup many searches. (cutting) 3. Restructured the Scorer API and all Scorer implementations to take advantage of an optimized TermDocs.skipTo() implementation. In particular, PhraseQuerys and conjunctive BooleanQuerys are faster when one clause has substantially fewer matches than the others. (A conjunctive BooleanQuery is a BooleanQuery where all clauses are required.) (cutting) 4. Added new class ParallelMultiSearcher. Combined with RemoteSearchable this makes it easy to implement distributed search systems. (Jean-Francois Halleux via cutting) 5. Added support for hit sorting. Results may now be sorted by any indexed field. For details see the javadoc for Searcher#search(Query, Sort). (Tim Jones via Cutting) 6. Changed FSDirectory to auto-create a full directory tree that it needs by using mkdirs() instead of mkdir(). (Mladen Turk via Otis) 7. Added a new span-based query API. This implements, among other things, nested phrases. See javadocs for details. (Doug Cutting) 8. Added new method Query.getSimilarity(Searcher), and changed scorers to use it. This permits one to subclass a Query class so that it can specify it's own Similarity implementation, perhaps one that delegates through that of the Searcher. (Julien Nioche via Cutting) 9. Added MultiReader, an IndexReader that combines multiple other IndexReaders. (Cutting) 10. Added support for term vectors. See Field#isTermVectorStored(). (Grant Ingersoll, Cutting &amp; Dmitry) 11. Fixed the old bug with escaping of special characters in query strings: http://issues.apache.org/bugzilla/show_bug.cgi?id=24665 (Jean-Francois Halleux via Otis) 12. Added support for overriding default values for the following, using system properties: - default commit lock timeout - default maxFieldLength - default maxMergeDocs - default mergeFactor - default minMergeDocs - default write lock timeout (Otis) 13. Changed QueryParser.jj to allow '-' and '+' within tokens: http://issues.apache.org/bugzilla/show_bug.cgi?id=27491 (Morus Walter via Otis) 14. Changed so that the compound index format is used by default. This makes indexing a bit slower, but vastly reduces the chances of file handle problems. (Cutting) 1.3 final 1. Added catch of BooleanQuery$TooManyClauses in QueryParser to throw ParseException instead. (Erik Hatcher) 2. Fixed a NullPointerException in Query.explain(). (Doug Cutting) 3. Added a new method IndexReader.setNorm(), that permits one to alter the boosting of fields after an index is created. 4. Distinguish between the final position and length when indexing a field. The length is now defined as the total number of tokens, instead of the final position, as it was previously. Length is used for score normalization (Similarity.lengthNorm()) and for controlling memory usage (IndexWriter.maxFieldLength). In both of these cases, the total number of tokens is a better value to use than the final token position. Position is used in phrase searching (see PhraseQuery and Token.setPositionIncrement()). 5. Fix StandardTokenizer's handling of CJK characters (Chinese, Japanese and Korean ideograms). Previously contiguous sequences were combined in a single token, which is not very useful. Now each ideogram generates a separate token, which is more useful. 1.3 RC3 1. Added minMergeDocs in IndexWriter. This can be raised to speed indexing without altering the number of files, but only using more memory. (Julien Nioche via Otis) 2. Fix bug #24786, in query rewriting. (bschneeman via Cutting) 3. Fix bug #16952, in demo HTML parser, skip comments in javascript. (Christoph Goller) 4. Fix bug #19253, in demo HTML parser, add whitespace as needed to output (Daniel Naber via Christoph Goller) 5. Fix bug #24301, in demo HTML parser, long titles no longer hang things. (Christoph Goller) 6. Fix bug #23534, Replace use of file timestamp of segments file with an index version number stored in the segments file. This resolves problems when running on file systems with low-resolution timestamps, e.g., HFS under MacOS X. (Christoph Goller) 7. Fix QueryParser so that TokenMgrError is not thrown, only ParseException. (Erik Hatcher) 8. Fix some bugs introduced by change 11 of RC2. (Christoph Goller) 9. Fixed a problem compiling TestRussianStem. (Christoph Goller) 10. Cleaned up some build stuff. (Erik Hatcher) 1.3 RC2 1. Added getFieldNames(boolean) to IndexReader, SegmentReader, and SegmentsReader. (Julien Nioche via otis) 2. Changed file locking to place lock files in System.getProperty("java.io.tmpdir"), where all users are permitted to write files. This way folks can open and correctly lock indexes which are read-only to them. 3. IndexWriter: added a new method, addDocument(Document, Analyzer), permitting one to easily use different analyzers for different documents in the same index. 4. Minor enhancements to FuzzyTermEnum. (Christoph Goller via Otis) 5. PriorityQueue: added insert(Object) method and adjusted IndexSearcher and MultiIndexSearcher to use it. (Christoph Goller via Otis) 6. Fixed a bug in IndexWriter that returned incorrect docCount(). (Christoph Goller via Otis) 7. Fixed SegmentsReader to eliminate the confusing and slightly different behaviour of TermEnum when dealing with an enumeration of all terms, versus an enumeration starting from a specific term. This patch also fixes incorrect term document frequences when the same term is present in multiple segments. (Christoph Goller via Otis) 8. Added CachingWrapperFilter and PerFieldAnalyzerWrapper. (Erik Hatcher) 9. Added support for the new "compound file" index format (Dmitry Serebrennikov) 10. Added Locale setting to QueryParser, for use by date range parsing. 11. Changed IndexReader so that it can be subclassed by classes outside of its package. Previously it had package-private abstract methods. Also modified the index merging code so that it can work on an arbitrary IndexReader implementation, and added a new method, IndexWriter.addIndexes(IndexReader[]), to take advantage of this. (cutting) 12. Added a limit to the number of clauses which may be added to a BooleanQuery. The default limit is 1024 clauses. This should stop most OutOfMemoryExceptions by prefix, wildcard and fuzzy queries which run amok. (cutting) 13. Add new method: IndexReader.undeleteAll(). This undeletes all deleted documents which still remain in the index. (cutting) 1.3 RC1 1. Fixed PriorityQueue's clear() method. Fix for bug 9454, http://nagoya.apache.org/bugzilla/show_bug.cgi?id=9454 (Matthijs Bomhoff via otis) 2. Changed StandardTokenizer.jj grammar for EMAIL tokens. Fix for bug 9015, http://nagoya.apache.org/bugzilla/show_bug.cgi?id=9015 (Dale Anson via otis) 3. Added the ability to disable lock creation by using disableLuceneLocks system property. This is useful for read-only media, such as CD-ROMs. (otis) 4. Added id method to Hits to be able to access the index global id. Required for sorting options. (carlson) 5. Added support for new range query syntax to QueryParser.jj. (briangoetz) 6. Added the ability to retrieve HTML documents' META tag values to HTMLParser.jj. (Mark Harwood via otis) 7. Modified QueryParser to make it possible to programmatically specify the default Boolean operator (OR or AND). (PÃ©ter HalÃ¡csy via otis) 8. Made many search methods and classes non-final, per requests. This includes IndexWriter and IndexSearcher, among others. (cutting) 9. Added class RemoteSearchable, providing support for remote searching via RMI. The test class RemoteSearchableTest.java provides an example of how this can be used. (cutting) 10. Added PhrasePrefixQuery (and supporting MultipleTermPositions). The test class TestPhrasePrefixQuery provides the usage example. (Anders Nielsen via otis) 11. Changed the German stemming algorithm to ignore case while stripping. The new algorithm is faster and produces more equal stems from nouns and verbs derived from the same word. (gschwarz) 12. Added support for boosting the score of documents and fields via the new methods Document.setBoost(float) and Field.setBoost(float). Note: This changes the encoding of an indexed value. Indexes should be re-created from scratch in order for search scores to be correct. With the new code and an old index, searches will yield very large scores for shorter fields, and very small scores for longer fields. Once the index is re-created, scores will be as before. (cutting) 13. Added new method Token.setPositionIncrement(). This permits, for the purpose of phrase searching, placing multiple terms in a single position. This is useful with stemmers that produce multiple possible stems for a word. This also permits the introduction of gaps between terms, so that terms which are adjacent in a token stream will not be matched by and exact phrase query. This makes it possible, e.g., to build an analyzer where phrases are not matched over stop words which have been removed. Finally, repeating a token with an increment of zero can also be used to boost scores of matches on that token. (cutting) 14. Added new Filter class, QueryFilter. This constrains search results to only match those which also match a provided query. Results are cached, so that searches after the first on the same index using this filter are very fast. This could be used, for example, with a RangeQuery on a formatted date field to implement date filtering. One could re-use a single QueryFilter that matches, e.g., only documents modified within the last week. The QueryFilter and RangeQuery would only need to be reconstructed once per day. (cutting) 15. Added a new IndexWriter method, getAnalyzer(). This returns the analyzer used when adding documents to this index. (cutting) 16. Fixed a bug with IndexReader.lastModified(). Before, document deletion did not update this. Now it does. (cutting) 17. Added Russian Analyzer. (Boris Okner via otis) 18. Added a public, extensible scoring API. For details, see the javadoc for org.apache.lucene.search.Similarity. 19. Fixed return of Hits.id() from float to int. (Terry Steichen via Peter). 20. Added getFieldNames() to IndexReader and Segment(s)Reader classes. (Peter Mularien via otis) 21. Added getFields(String) and getValues(String) methods. Contributed by Rasik Pandey on 2002-10-09 (Rasik Pandey via otis) 22. Revised internal search APIs. Changes include: a. Queries are no longer modified during a search. This makes it possible, e.g., to reuse the same query instance with multiple indexes from multiple threads. b. Term-expanding queries (e.g. PrefixQuery, WildcardQuery, etc.) now work correctly with MultiSearcher, fixing bugs 12619 and 12667. c. Boosting BooleanQuery's now works, and is supported by the query parser (problem reported by Lee Mallabone). Thus a query like "(+foo +bar)^2 +baz" is now supported and equivalent to "(+foo^2 +bar^2) +baz". d. New method: Query.rewrite(IndexReader). This permits a query to re-write itself as an alternate, more primitive query. Most of the term-expanding query classes (PrefixQuery, WildcardQuery, etc.) are now implemented using this method. e. New method: Searchable.explain(Query q, int doc). This returns an Explanation instance that describes how a particular document is scored against a query. An explanation can be displayed as either plain text, with the toString() method, or as HTML, with the toHtml() method. Note that computing an explanation is as expensive as executing the query over the entire index. This is intended to be used in developing Similarity implementations, and, for good performance, should not be displayed with every hit. f. Scorer and Weight are public, not package protected. It now possible for someone to write a Scorer implementation that is not in the org.apache.lucene.search package. This is still fairly advanced programming, and I don't expect anyone to do this anytime soon, but at least now it is possible. g. Added public accessors to the primitive query classes (TermQuery, PhraseQuery and BooleanQuery), permitting access to their terms and clauses. Caution: These are extensive changes and they have not yet been tested extensively. Bug reports are appreciated. (cutting) 23. Added convenience RAMDirectory constructors taking File and String arguments, for easy FSDirectory to RAMDirectory conversion. (otis) 24. Added code for manual renaming of files in FSDirectory, since it has been reported that java.io.File's renameTo(File) method sometimes fails on Windows JVMs. (Matt Tucker via otis) 25. Refactored QueryParser to make it easier for people to extend it. Added the ability to automatically lower-case Wildcard terms in the QueryParser. (Tatu Saloranta via otis) 1.2 RC6 1. Changed QueryParser.jj to have "?" be a special character which allowed it to be used as a wildcard term. Updated TestWildcard unit test also. (Ralf Hettesheimer via carlson) 1.2 RC5 1. Renamed build.properties to default.properties and updated the BUILD.txt document to describe how to override the default.property settings without having to edit the file. This brings the build process closer to Scarab's build process. (jon) 2. Added MultiFieldQueryParser class. (Kelvin Tan, via otis) 3. Updated "powered by" links. (otis) 4. Fixed instruction for setting up JavaCC - Bug #7017 (otis) 5. Added throwing exception if FSDirectory could not create diectory - Bug #6914 (Eugene Gluzberg via otis) 6. Update MultiSearcher, MultiFieldParse, Constants, DateFilter, LowerCaseTokenizer javadoc (otis) 7. Added fix to avoid NullPointerException in results.jsp (Mark Hayes via otis) 8. Changed Wildcard search to find 0 or more char instead of 1 or more (Lee Mallobone, via otis) 9. Fixed error in offset issue in GermanStemFilter - Bug #7412 (Rodrigo Reyes, via otis) 10. Added unit tests for wildcard search and DateFilter (otis) 11. Allow co-existence of indexed and non-indexed fields with the same name (cutting/casper, via otis) 12. Add escape character to query parser. (briangoetz) 13. Applied a patch that ensures that searches that use DateFilter don't throw an exception when no matches are found. (David Smiley, via otis) 14. Fixed bugs in DateFilter and wildcardquery unit tests. (cutting, otis, carlson) 1.2 RC4 1. Updated contributions section of website. Add XML Document #3 implementation to Document Section. Also added Term Highlighting to Misc Section. (carlson) 2. Fixed NullPointerException for phrase searches containing unindexed terms, introduced in 1.2RC3. (cutting) 3. Changed document deletion code to obtain the index write lock, enforcing the fact that document addition and deletion cannot be performed concurrently. (cutting) 4. Various documentation cleanups. (otis, acoliver) 5. Updated "powered by" links. (cutting, jon) 6. Fixed a bug in the GermanStemmer. (Bernhard Messer, via otis) 7. Changed Term and Query to implement Serializable. (scottganyo) 8. Fixed to never delete indexes added with IndexWriter.addIndexes(). (cutting) 9. Upgraded to JUnit 3.7. (otis) 1.2 RC3 1. IndexWriter: fixed a bug where adding an optimized index to an empty index failed. This was encountered using addIndexes to copy a RAMDirectory index to an FSDirectory. 2. RAMDirectory: fixed a bug where RAMInputStream could not read across more than across a single buffer boundary. 3. Fix query parser so it accepts queries with unicode characters. (briangoetz) 4. Fix query parser so that PrefixQuery is used in preference to WildcardQuery when there's only an asterisk at the end of the term. Previously PrefixQuery would never be used. 5. Fix tests so they compile; fix ant file so it compiles tests properly. Added test cases for Analyzers and PriorityQueue. 6. Updated demos, added Getting Started documentation. (acoliver) 7. Added 'contributions' section to website &amp; docs. (carlson) 8. Removed JavaCC from source distribution for copyright reasons. Folks must now download this separately from metamata in order to compile Lucene. (cutting) 9. Substantially improved the performance of DateFilter by adding the ability to reuse TermDocs objects. (cutting) 10. Added IndexReader methods: public static boolean indexExists(String directory); public static boolean indexExists(File directory); public static boolean indexExists(Directory directory); public static boolean isLocked(Directory directory); public static void unlock(Directory directory); (cutting, otis) 11. Fixed bugs in GermanAnalyzer (gschwarz) 1.2 RC2, 19 October 2001: - added sources to distribution - removed broken build scripts and libraries from distribution - SegmentsReader: fixed potential race condition - FSDirectory: fixed so that getDirectory(xxx,true) correctly erases the directory contents, even when the directory has already been accessed in this JVM. - RangeQuery: Fix issue where an inclusive range query would include the nearest term in the index above a non-existant specified upper term. - SegmentTermEnum: Fix NullPointerException in clone() method when the Term is null. - JDK 1.1 compatibility fix: disabled lock files for JDK 1.1, since they rely on a feature added in JDK 1.2. 1.2 RC1 (first Apache release), 2 October 2001: - packages renamed from com.lucene to org.apache.lucene - license switched from LGPL to Apache - ant-only build -- no more makefiles - addition of lock files--now fully thread &amp; process safe - addition of German stemmer - MultiSearcher now supports low-level search API - added RangeQuery, for term-range searching - Analyzers can choose tokenizer based on field name - misc bug fixes. 1.01b (last Sourceforge release), 2 July 2001 . a few bug fixes . new Query Parser . new prefix query (search for "foo*" matches "food") 1.0, 2000-10-04 This release fixes a few serious bugs and also includes some performance optimizations, a stemmer, and a few other minor enhancements. 0.04 2000-04-19 Lucene now includes a grammar-based tokenizer, StandardTokenizer. The only tokenizer included in the previous release (LetterTokenizer) identified terms consisting entirely of alphabetic characters. The new tokenizer uses a regular-expression grammar to identify more complex classes of terms, including numbers, acronyms, email addresses, etc. StandardTokenizer serves two purposes: 1. It is a much better, general purpose tokenizer for use by applications as is. The easiest way for applications to start using StandardTokenizer is to use StandardAnalyzer. 2. It provides a good example of grammar-based tokenization. If an application has special tokenization requirements, it can implement a custom tokenizer by copying the directory containing the new tokenizer into the application and modifying it accordingly. 0.01, 2000-03-30 First open source release. The code has been re-organized into a new package and directory structure for this release. It builds OK, but has not been tested beyond that since the re-organization.</cjk></cj>

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