Class CapitalizationFilter

  • All Implemented Interfaces:
    Closeable, AutoCloseable

    public final class CapitalizationFilter
    extends TokenFilter
    A filter to apply normal capitalization rules to Tokens. It will make the first letter capital and the rest lower case.

    This filter is particularly useful to build nice looking facet parameters. This filter is not appropriate if you intend to use a prefix query.

    • Constructor Detail

      • CapitalizationFilter

        public CapitalizationFilter​(TokenStream in,
                                    boolean onlyFirstWord,
                                    CharArraySet keep,
                                    boolean forceFirstLetter,
                                    Collection<char[]> okPrefix,
                                    int minWordLength,
                                    int maxWordCount,
                                    int maxTokenLength)
        Creates a CapitalizationFilter with the specified parameters.
        in - input tokenstream
        onlyFirstWord - should each word be capitalized or all of the words?
        keep - a keep word list. Each word that should be kept separated by whitespace.
        forceFirstLetter - Force the first letter to be capitalized even if it is in the keep list.
        okPrefix - do not change word capitalization if a word begins with something in this list.
        minWordLength - how long the word needs to be to get capitalization applied. If the minWordLength is 3, "and" > "And" but "or" stays "or".
        maxWordCount - if the token contains more then maxWordCount words, the capitalization is assumed to be correct.
        maxTokenLength - ???
    • Method Detail

      • incrementToken

        public 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
        false for end of stream; true otherwise