org.apache.lucene.analysis.custom

## Class CustomAnalyzer

- java.lang.Object
- - org.apache.lucene.analysis.Analyzer
  - - org.apache.lucene.analysis.custom.CustomAnalyzer

- All Implemented Interfaces:
    Closeable, AutoCloseable

      public final class CustomAnalyzer
      extends Analyzer

  A general-purpose Analyzer that can be created with a builder-style API. Under the hood it uses the factory classes `TokenizerFactory`, `TokenFilterFactory`, and `CharFilterFactory`.

  You can create an instance of this Analyzer using the builder:

       Analyzer ana = CustomAnalyzer.builder(Paths.get("/path/to/config/dir"))
         .withTokenizer(StandardTokenizerFactory.class)
         .addTokenFilter(StandardFilterFactory.class)
         .addTokenFilter(LowerCaseFilterFactory.class)
         .addTokenFilter(StopFilterFactory.class, "ignoreCase", "false", "words", "stopwords.txt", "format", "wordset")
         .build();

  The parameters passed to components are also used by Apache Solr and are documented on their corresponding factory classes. Refer to documentation of subclasses of `TokenizerFactory`, `TokenFilterFactory`, and `CharFilterFactory`.

  You can also use the SPI names (as defined by `ServiceLoader` interface):

       Analyzer ana = CustomAnalyzer.builder(Paths.get("/path/to/config/dir"))
         .withTokenizer("standard")
         .addTokenFilter("standard")
         .addTokenFilter("lowercase")
         .addTokenFilter("stop", "ignoreCase", "false", "words", "stopwords.txt", "format", "wordset")
         .build();

  The list of names to be used for components can be looked up through: `TokenizerFactory.availableTokenizers()`, `TokenFilterFactory.availableTokenFilters()`, and `CharFilterFactory.availableCharFilters()`.

  You can create conditional branches in the analyzer by using `CustomAnalyzer.Builder.when(String, String...)` and `CustomAnalyzer.Builder.whenTerm(Predicate)`:

       Analyzer ana = CustomAnalyzer.builder()
          .withTokenizer("standard")
          .addTokenFilter("lowercase")
          .whenTerm(t -> t.length() > 10)
            .addTokenFilter("reversestring")
          .endwhen()
          .build();

  Since:
    5.0.0

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `CustomAnalyzer.Builder` Builder for `CustomAnalyzer`.
    `static class` | `CustomAnalyzer.ConditionBuilder` Factory class for a `ConditionalTokenFilter`

    - ### Nested classes/interfaces inherited from class org.apache.lucene.analysis.Analyzer

      `Analyzer.ReuseStrategy, Analyzer.TokenStreamComponents`

  - ### Field Summary

    - ### Fields inherited from class org.apache.lucene.analysis.Analyzer

      `GLOBAL_REUSE_STRATEGY, PER_FIELD_REUSE_STRATEGY`

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static CustomAnalyzer.Builder` | `builder()` Returns a builder for custom analyzers that loads all resources from Lucene's classloader.
    `static CustomAnalyzer.Builder` | `builder(Path configDir)` Returns a builder for custom analyzers that loads all resources from the given file system base directory.
    `static CustomAnalyzer.Builder` | `builder(ResourceLoader loader)` Returns a builder for custom analyzers that loads all resources using the given `ResourceLoader`.
    `protected Analyzer.TokenStreamComponents` | `createComponents(String fieldName)`
    `List<CharFilterFactory>` | `getCharFilterFactories()` Returns the list of char filters that are used in this analyzer.
    `int` | `getOffsetGap(String fieldName)`
    `int` | `getPositionIncrementGap(String fieldName)`
    `List<TokenFilterFactory>` | `getTokenFilterFactories()` Returns the list of token filters that are used in this analyzer.
    `TokenizerFactory` | `getTokenizerFactory()` Returns the tokenizer that is used in this analyzer.
    `protected Reader` | `initReader(String fieldName, Reader reader)`
    `protected Reader` | `initReaderForNormalization(String fieldName, Reader reader)`
    `protected TokenStream` | `normalize(String fieldName, TokenStream in)`
    `String` | `toString()`

    - ### Methods inherited from class org.apache.lucene.analysis.Analyzer

      `attributeFactory, close, getReuseStrategy, getVersion, normalize, setVersion, tokenStream, tokenStream`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

- - ### Method Detail

    - #### builder

          public static CustomAnalyzer.Builder builder()

      Returns a builder for custom analyzers that loads all resources from Lucene's classloader. All path names given must be absolute with package prefixes.

    - #### builder

          public static CustomAnalyzer.Builder builder(Path configDir)

      Returns a builder for custom analyzers that loads all resources from the given file system base directory. Place, e.g., stop word files there. Files that are not in the given directory are loaded from Lucene's classloader.

    - #### builder

          public static CustomAnalyzer.Builder builder(ResourceLoader loader)

      Returns a builder for custom analyzers that loads all resources using the given `ResourceLoader`.

    - #### initReader

          protected Reader initReader(String fieldName,
                                      Reader reader)

      Overrides:
        `initReader` in class `Analyzer`

    - #### initReaderForNormalization

          protected Reader initReaderForNormalization(String fieldName,
                                                      Reader reader)

      Overrides:
        `initReaderForNormalization` in class `Analyzer`

    - #### createComponents

          protected Analyzer.TokenStreamComponents createComponents(String fieldName)

      Specified by:
        `createComponents` in class `Analyzer`

    - #### normalize

          protected TokenStream normalize(String fieldName,
                                          TokenStream in)

      Overrides:
        `normalize` in class `Analyzer`

    - #### getPositionIncrementGap

          public int getPositionIncrementGap(String fieldName)

      Overrides:
        `getPositionIncrementGap` in class `Analyzer`

    - #### getOffsetGap

          public int getOffsetGap(String fieldName)

      Overrides:
        `getOffsetGap` in class `Analyzer`

    - #### getCharFilterFactories

          public List<CharFilterFactory> getCharFilterFactories()

      Returns the list of char filters that are used in this analyzer.

    - #### getTokenizerFactory

          public TokenizerFactory getTokenizerFactory()

      Returns the tokenizer that is used in this analyzer.

    - #### getTokenFilterFactories

          public List<TokenFilterFactory> getTokenFilterFactories()

      Returns the list of token filters that are used in this analyzer.

    - #### toString

          public String toString()

      Overrides:
        `toString` in class `Object`

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