public final class ICUTransformFilter extends TokenFilter
TokenFilter that transforms text with ICU.
ICU provides text-transformation functionality via its Transliteration API. Although script conversion is its most common use, a Transliterator can actually perform a more general class of tasks. In fact, Transliterator defines a very general API which specifies only that a segment of the input text is replaced by new text. The particulars of this conversion are determined entirely by subclasses of Transliterator.
Some useful transformations for search are built-in:
Example usage:
stream = new ICUTransformFilter(stream, Transliterator.getInstance("Traditional-Simplified"));For more details, see the ICU User Guide.
AttributeSource.AttributeFactory, AttributeSource.Stateinput| Constructor and Description |
|---|
ICUTransformFilter(TokenStream input,
com.ibm.icu.text.Transliterator transform)
Create a new ICUTransformFilter that transforms text on the given stream.
|
| Modifier and Type | Method and Description |
|---|---|
boolean |
incrementToken()
Consumers (i.e.,
IndexWriter) use this method to advance the stream to
the next token. |
close, end, resetaddAttribute, addAttributeImpl, captureState, clearAttributes, cloneAttributes, copyTo, equals, getAttribute, getAttributeClassesIterator, getAttributeFactory, getAttributeImplsIterator, hasAttribute, hasAttributes, hashCode, reflectAsString, reflectWith, restoreState, toStringpublic ICUTransformFilter(TokenStream input, com.ibm.icu.text.Transliterator transform)
input - TokenStream to filter.transform - Transliterator to transform the text.public boolean incrementToken()
throws IOException
TokenStreamIndexWriter) 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().
incrementToken in class TokenStreamIOException