CachingTokenFilter (Lucene 2.4.1 API)
Keywords: org.apache.lucene.analysis.CachingTokenFilter class

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## org.apache.lucene.analysis
Class CachingTokenFilter

    java.lang.Object
      org.apache.lucene.analysis.TokenStream
          org.apache.lucene.analysis.TokenFilter
              org.apache.lucene.analysis.CachingTokenFilter

    public class CachingTokenFilter

extends TokenFilter

This class can be used if the Tokens of a TokenStream are intended to be consumed more than once. It caches all Tokens locally in a List. CachingTokenFilter implements the optional method `TokenStream.reset()`, which repositions the stream to the first Token.

Field Summary

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

Constructor Summary
`CachingTokenFilter(TokenStream input)`

Method Summary
`Token` | `next(Token reusableToken)` Returns the next token in the stream, or null at EOS.
`void` | `reset()` Reset the filter as well as the input TokenStream.

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

Methods inherited from class org.apache.lucene.analysis.TokenStream
`next`

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

Constructor Detail

### CachingTokenFilter

    public CachingTokenFilter(TokenStream input)

Method Detail

### next

    public Token next(Token reusableToken)
               throws IOException

  Description copied from class: `TokenStream`
  Returns the next token in the stream, or null at EOS. When possible, the input Token should be used as the returned Token (this gives fastest tokenization performance), but this is not required and a new Token may be returned. Callers may re-use a single Token instance for successive calls to this method.

  This implicitly defines a "contract" between consumers (callers of this method) and producers (implementations of this method that are the source for tokens):

  - A consumer must fully consume the previously returned Token before calling this method again.
  - A producer must call `Token.clear()` before setting the fields in it & returning it
  Also, the producer must make no assumptions about a Token after it has been returned: the caller may arbitrarily change it. If the producer needs to hold onto the token for subsequent calls, it must clone() it before storing it. Note that a `TokenFilter` is considered a consumer.

  Overrides:
    `next` in class `TokenStream`
  Parameters:
    `reusableToken` - a Token that may or may not be used to return; this parameter should never be null (the callee is not required to check for null before using it, but it is a good idea to assert that it is not null.)
  Returns:
    next token in the stream or null if end-of-stream was hit
  Throws:
    `IOException`

### reset

    public void reset()
               throws IOException

  Description copied from class: `TokenFilter`
  Reset the filter as well as the input TokenStream.

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

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