Package 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`, `AutoCloseable`, `Unwrappable<TokenStream>`

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.State`

## Field Summary

### Fields inherited from class org.apache.lucene.analysis.TokenFilter

`input`

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

`DEFAULT_TOKEN_ATTRIBUTE_FACTORY`

## Constructor Summary

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

## Method Summary

Modifier and Type
Method
Description
`boolean`
`incrementToken()`
`void`
`reset()`

### Methods inherited from class org.apache.lucene.analysis.TokenFilter

`close, end, unwrap`

### 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`

## Constructor Details

### 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 Details

### 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`