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## org.apache.lucene.analysis.miscellaneous
Class PrefixAwareTokenFilter

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

All Implemented Interfaces:
  Closeable

    public class PrefixAwareTokenFilter

extends TokenStream

Joins two token streams and leaves the last token of the first stream available to be used when updating the token values in the second stream based on that token. The default implementation adds last prefix token end offset to the suffix token start and end offsets.

NOTE: This filter might not behave correctly if used with custom Attributes, i.e. Attributes other than the ones located in org.apache.lucene.analysis.tokenattributes.

Nested Class Summary

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

Constructor Summary
`PrefixAwareTokenFilter(TokenStream prefix, TokenStream suffix)`

Method Summary
`void` | `close()` Releases resources associated with this stream.
`void` | `end()` This method is called by the consumer after the last token has been consumed, after `TokenStream.incrementToken()` returned `false` (using the new `TokenStream` API).
`TokenStream` | `getPrefix()`
`TokenStream` | `getSuffix()`
`boolean` | `incrementToken()` Consumers (i.e., `IndexWriter`) use this method to advance the stream to the next token.
`void` | `reset()` Resets this stream to the beginning.
`void` | `setPrefix(TokenStream prefix)`
`void` | `setSuffix(TokenStream suffix)`
`Token` | `updateSuffixToken(Token suffixToken, Token lastPrefixToken)` The default implementation adds last prefix token end offset to the suffix token start and end offsets.

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, toString`

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

Constructor Detail

### PrefixAwareTokenFilter

    public PrefixAwareTokenFilter(TokenStream prefix,
                                  TokenStream suffix)

Method Detail

### incrementToken

    public final boolean incrementToken()
                                 throws IOException

  Description copied from class: `TokenStream`
  Consumers (i.e., `IndexWriter`) use this method to advance the stream to the next token. Implementing classes must implement this method and update the appropriate `AttributeImpl`s with the attributes of the next token.

  The producer must make no assumptions about the attributes after the method has been returned: the caller may arbitrarily change it. If the producer needs to preserve the state for subsequent calls, it can use `AttributeSource.captureState()` to create a copy of the current attribute state.

  This method is called for every token of a document, so an efficient implementation is crucial for good performance. To avoid calls to `AttributeSource.addAttribute(Class)` and `AttributeSource.getAttribute(Class)`, references to all `AttributeImpl`s that this stream uses should be retrieved during instantiation.

  To ensure that filters and consumers know which attributes are available, the attributes must be added during instantiation. Filters and consumers are not required to check for availability of attributes in `TokenStream.incrementToken()`.

  Specified by:
    `incrementToken` in class `TokenStream`
  Returns:
    false for end of stream; true otherwise
  Throws:
    `IOException`

### updateSuffixToken

    public Token updateSuffixToken(Token suffixToken,
                                   Token lastPrefixToken)

  The default implementation adds last prefix token end offset to the suffix token start and end offsets.

  Parameters:
    `suffixToken` - a token from the suffix stream
    `lastPrefixToken` - the last token from the prefix stream
  Returns:
    consumer token

### end

    public void end()
             throws IOException

  Description copied from class: `TokenStream`
  This method is called by the consumer after the last token has been consumed, after `TokenStream.incrementToken()` returned `false` (using the new `TokenStream` API). Streams implementing the old API should upgrade to use this feature.

  This method can be used to perform any end-of-stream operations, such as setting the final offset of a stream. The final offset of a stream might differ from the offset of the last token eg in case one or more whitespaces followed after the last token, but a `WhitespaceTokenizer` was used.

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

### close

    public void close()
               throws IOException

  Description copied from class: `TokenStream`
  Releases resources associated with this stream.

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

### reset

    public void reset()
               throws IOException

  Description copied from class: `TokenStream`
  Resets this stream to the beginning. This is an optional operation, so subclasses may or may not implement this method. `TokenStream.reset()` is not needed for the standard indexing process. However, if the tokens of a `TokenStream` are intended to be consumed more than once, it is necessary to implement `TokenStream.reset()`. Note that if your TokenStream caches tokens and feeds them back again after a reset, it is imperative that you clone the tokens when you store them away (on the first pass) as well as when you return them (on future passes after `TokenStream.reset()`).

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

### getPrefix

    public TokenStream getPrefix()

### setPrefix

    public void setPrefix(TokenStream prefix)

### getSuffix

    public TokenStream getSuffix()

### setSuffix

    public void setSuffix(TokenStream suffix)

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