org.apache.lucene.analysis.miscellaneous

## Class ConcatenateGraphFilter

- java.lang.Object
- - org.apache.lucene.util.AttributeSource
  - - org.apache.lucene.analysis.TokenStream
    - - org.apache.lucene.analysis.miscellaneous.ConcatenateGraphFilter

- All Implemented Interfaces:
    Closeable, AutoCloseable

      public final class ConcatenateGraphFilter
      extends TokenStream

  Concatenates/Joins every incoming token with a separator into one output token for every path through the token stream (which is a graph). In simple cases this yields one token, but in the presence of any tokens with a zero positionIncrmeent (e.g. synonyms) it will be more. This filter uses the token bytes, position increment, and position length of the incoming stream. Other attributes are not used or manipulated.
  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static interface` | `ConcatenateGraphFilter.BytesRefBuilderTermAttribute` Attribute providing access to the term builder and UTF-16 conversion
    `static class` | `ConcatenateGraphFilter.BytesRefBuilderTermAttributeImpl` Implementation of `ConcatenateGraphFilter.BytesRefBuilderTermAttribute`

    - ### Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

      `AttributeSource.State`

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `DEFAULT_MAX_GRAPH_EXPANSIONS`
    `static boolean` | `DEFAULT_PRESERVE_POSITION_INCREMENTS`
    `static boolean` | `DEFAULT_PRESERVE_SEP`
    `static int` | `SEP_LABEL` Represents the separation between tokens, if `preserveSep` is `true`.

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

      `DEFAULT_TOKEN_ATTRIBUTE_FACTORY`

  - ### Constructor Summary

    Constructors
    Constructor and Description
    `ConcatenateGraphFilter(TokenStream inputTokenStream)` Creates a token stream to convert `input` to a token stream of accepted strings by its token stream graph.
    `ConcatenateGraphFilter(TokenStream inputTokenStream, boolean preserveSep, boolean preservePositionIncrements, int maxGraphExpansions)` Creates a token stream to convert `input` to a token stream of accepted strings by its token stream graph.

  - ### Method Summary

    All Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `void` | `close()`
    `void` | `end()`
    `boolean` | `incrementToken()`
    `void` | `reset()`
    `Automaton` | `toAutomaton()` Converts the tokenStream to an automaton, treating the transition labels as utf-8.
    `Automaton` | `toAutomaton(boolean unicodeAware)` Converts the tokenStream to an automaton.

    - ### Methods inherited from class org.apache.lucene.util.AttributeSource

      `addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, endAttributes, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, removeAllAttributes, restoreState, toString`

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

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

- - ### Field Detail

    - #### SEP_LABEL

          public static final int SEP_LABEL

      Represents the separation between tokens, if `preserveSep` is `true`.
      See Also:
        Constant Field Values

    - #### DEFAULT_MAX_GRAPH_EXPANSIONS

          public static final int DEFAULT_MAX_GRAPH_EXPANSIONS

      See Also:
        Constant Field Values

    - #### DEFAULT_PRESERVE_SEP

          public static final boolean DEFAULT_PRESERVE_SEP

      See Also:
        Constant Field Values

    - #### DEFAULT_PRESERVE_POSITION_INCREMENTS

          public static final boolean DEFAULT_PRESERVE_POSITION_INCREMENTS

      See Also:
        Constant Field Values

  - ### Constructor Detail

    - #### ConcatenateGraphFilter

          public ConcatenateGraphFilter(TokenStream inputTokenStream)

      Creates a token stream to convert `input` to a token stream of accepted strings by its token stream graph.

      This constructor uses the default settings of the constants in this class.

    - #### ConcatenateGraphFilter

          public ConcatenateGraphFilter(TokenStream inputTokenStream,
                                        boolean preserveSep,
                                        boolean preservePositionIncrements,
                                        int maxGraphExpansions)

      Creates a token stream to convert `input` to a token stream of accepted strings by its token stream graph.
      Parameters:
        `inputTokenStream` - The input/incoming TokenStream
        `preserveSep` - Whether `SEP_LABEL` should separate the input tokens in the concatenated token
        `preservePositionIncrements` - Whether to add an empty token for missing positions. The effect is a consecutive `SEP_LABEL`. When false, it's as if there were no missing positions (we pretend the surrounding tokens were adjacent).
        `maxGraphExpansions` - If the tokenStream graph has more than this many possible paths through, then we'll throw `TooComplexToDeterminizeException` to preserve the stability and memory of the machine.
      Throws:
        `TooComplexToDeterminizeException` - if the tokenStream graph has more than `maxGraphExpansions` expansions

  - ### Method Detail

    - #### reset

          public void reset()
                     throws IOException

      Overrides:
        `reset` in class `TokenStream`
      Throws:
        `IOException`

    - #### incrementToken

          public boolean incrementToken()
                                 throws IOException

      Specified by:
        `incrementToken` in class `TokenStream`
      Throws:
        `IOException`

    - #### end

          public void end()
                   throws IOException

      Overrides:
        `end` in class `TokenStream`
      Throws:
        `IOException`

    - #### close

          public void close()
                     throws IOException

      Specified by:
        `close` in interface `Closeable`
      Specified by:
        `close` in interface `AutoCloseable`
      Overrides:
        `close` in class `TokenStream`
      Throws:
        `IOException`

    - #### toAutomaton

          public Automaton toAutomaton()
                                throws IOException

      Converts the tokenStream to an automaton, treating the transition labels as utf-8. Does *not* close it.
      Throws:
        `IOException`

    - #### toAutomaton

          public Automaton toAutomaton(boolean unicodeAware)
                                throws IOException

      Converts the tokenStream to an automaton. Does *not* close it.
      Throws:
        `IOException`

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