Package org.apache.lucene.analysis.core

Class UpperCaseFilter

java.lang.Object
org.apache.lucene.util.AttributeSource
org.apache.lucene.analysis.TokenStream
org.apache.lucene.analysis.TokenFilter
org.apache.lucene.analysis.core.UpperCaseFilter
All Implemented Interfaces:
Closeable, AutoCloseable
public final class UpperCaseFilter extends TokenFilter
Normalizes token text to UPPER CASE.

You must specify the required Version compatibility when creating UpperCaseFilter

NOTE: In Unicode, this transformation may lose information when the upper case character represents more than one lower case character. Use this filter when you require uppercase tokens. Use the LowerCaseFilter for general search matching

  • Constructor Details

    • UpperCaseFilter

      public UpperCaseFilter(Version matchVersion, TokenStream in)
      Create a new UpperCaseFilter, that normalizes token text to upper case.
      Parameters:
      matchVersion - See above
      in - TokenStream to filter

  • Method Details

    • 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 AttributeImpls 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 AttributeImpls 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