## org.apache.lucene.analysis.pattern
Class PatternCaptureGroupTokenFilter

    java.lang.Object
      org.apache.lucene.util.AttributeSource
          org.apache.lucene.analysis.TokenStream
              org.apache.lucene.analysis.TokenFilter
                  org.apache.lucene.analysis.pattern.PatternCaptureGroupTokenFilter

All Implemented Interfaces:
  Closeable

    public final class PatternCaptureGroupTokenFilter

extends TokenFilter

CaptureGroup uses Java regexes to emit multiple tokens - one for each capture group in one or more patterns.

For example, a pattern like:

`"(https?://([a-zA-Z\-_0-9.]+))"`

when matched against the string "http://www.foo.com/index" would return the tokens "https://www.foo.com" and "www.foo.com".

If none of the patterns match, or if preserveOriginal is true, the original token will be preserved.

Each pattern is matched as often as it can be, so the pattern `"(...)"`, when matched against `"abcdefghi"` would produce `["abc","def","ghi"]`

A camelCaseFilter could be written as:

`"([A-Z]{2,})",
"(?<![A-Z])([A-Z][a-z]+)",
"(?:^|\\b|(?<=[0-9_])|(?<=[A-Z]{2}))([a-z]+)",
"([0-9]+)"`

plus if `preserveOriginal` is true, it would also return `"camelCaseFilter`

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource
`AttributeSource.AttributeFactory, AttributeSource.State`

Field Summary

Fields inherited from class org.apache.lucene.analysis.TokenFilter
`input`

Constructor Summary
`PatternCaptureGroupTokenFilter(TokenStream input, boolean preserveOriginal, Pattern... patterns)`

Method Summary
`boolean` `incrementToken()`
`void` `reset()`

Methods inherited from class org.apache.lucene.analysis.TokenFilter
`close, end`

Methods inherited from class org.apache.lucene.util.AttributeSource
`addAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState`

Methods inherited from class java.lang.Object
`clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait`

Constructor Detail

### PatternCaptureGroupTokenFilter

    public PatternCaptureGroupTokenFilter(TokenStream input,
                                          boolean preserveOriginal,
                                          Pattern... patterns)

Parameters:
  `input` - the input `TokenStream`
  `preserveOriginal` - set to true to return the original token even if one of the patterns matches
  `patterns` - an array of `Pattern` objects to match against each token

Method Detail

### incrementToken

    public boolean incrementToken()
                           throws IOException

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

### reset

    public void reset()
               throws IOException

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

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