Package org.apache.lucene.analysis.miscellaneous

Class CapitalizationFilter

java.lang.Object

org.apache.lucene.util.AttributeSource

org.apache.lucene.analysis.TokenStream

org.apache.lucene.analysis.TokenFilter

org.apache.lucene.analysis.miscellaneous.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.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.lucene.util.AttributeSource

AttributeSource.AttributeFactory, AttributeSource.State

Field Summary

Fields

Modifier and Type	Field	Description
static final int	DEFAULT_MAX_TOKEN_LENGTH
static final int	DEFAULT_MAX_WORD_COUNT

Constructor Summary

Constructors

Constructor	Description
CapitalizationFilter(TokenStream in)	Creates a CapitalizationFilter with the default parameters.
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.

Method Summary

Modifier and Type	Method	Description
boolean	incrementToken()	Consumers (i.e., IndexWriter) use this method to advance the stream to the next token.

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

close, end, reset

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

getClass, notify, notifyAll, wait, wait, wait

Field Details

DEFAULT_MAX_WORD_COUNT

public static final int DEFAULT_MAX_WORD_COUNT

See Also:

• Constant Field Values

DEFAULT_MAX_TOKEN_LENGTH

public static final int DEFAULT_MAX_TOKEN_LENGTH

See Also:

• Constant Field Values

Constructor Details

CapitalizationFilter

public CapitalizationFilter(TokenStream in)

Creates a CapitalizationFilter with the default parameters.

Calls CapitalizationFilter(in, true, null, true, null, 0, DEFAULT_MAX_WORD_COUNT, DEFAULT_MAX_TOKEN_LENGTH)

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.

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 Details

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

Returns:

false for end of stream; true otherwise

Throws:

IOException