+++ /dev/null
-/**
- * Licensed to the Apache Software Foundation (ASF) under one or more
- * contributor license agreements. See the NOTICE file distributed with
- * this work for additional information regarding copyright ownership.
- * The ASF licenses this file to You under the Apache License, Version 2.0
- * (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.apache.lucene.analysis;
-
-import java.io.IOException;
-import java.io.Reader;
-
-/**
- * An convenience subclass of Analyzer that makes it easy to implement
- * {@link TokenStream} reuse.
- * <p>
- * ReusableAnalyzerBase is a simplification of Analyzer that supports easy reuse
- * for the most common use-cases. Analyzers such as
- * {@link PerFieldAnalyzerWrapper} that behave differently depending upon the
- * field name need to subclass Analyzer directly instead.
- * </p>
- * <p>
- * To prevent consistency problems, this class does not allow subclasses to
- * extend {@link #reusableTokenStream(String, Reader)} or
- * {@link #tokenStream(String, Reader)} directly. Instead, subclasses must
- * implement {@link #createComponents(String, Reader)}.
- * </p>
- */
-public abstract class ReusableAnalyzerBase extends Analyzer {
-
- /**
- * Creates a new {@link TokenStreamComponents} instance for this analyzer.
- *
- * @param fieldName
- * the name of the fields content passed to the
- * {@link TokenStreamComponents} sink as a reader
- * @param aReader
- * the reader passed to the {@link Tokenizer} constructor
- * @return the {@link TokenStreamComponents} for this analyzer.
- */
- protected abstract TokenStreamComponents createComponents(String fieldName,
- Reader aReader);
-
- /**
- * This method uses {@link #createComponents(String, Reader)} to obtain an
- * instance of {@link TokenStreamComponents}. It returns the sink of the
- * components and stores the components internally. Subsequent calls to this
- * method will reuse the previously stored components if and only if the
- * {@link TokenStreamComponents#reset(Reader)} method returned
- * <code>true</code>. Otherwise a new instance of
- * {@link TokenStreamComponents} is created.
- *
- * @param fieldName the name of the field the created TokenStream is used for
- * @param reader the reader the streams source reads from
- */
- @Override
- public final TokenStream reusableTokenStream(final String fieldName,
- final Reader reader) throws IOException {
- TokenStreamComponents streamChain = (TokenStreamComponents)
- getPreviousTokenStream();
- final Reader r = initReader(reader);
- if (streamChain == null || !streamChain.reset(r)) {
- streamChain = createComponents(fieldName, r);
- setPreviousTokenStream(streamChain);
- }
- return streamChain.getTokenStream();
- }
-
- /**
- * This method uses {@link #createComponents(String, Reader)} to obtain an
- * instance of {@link TokenStreamComponents} and returns the sink of the
- * components. Each calls to this method will create a new instance of
- * {@link TokenStreamComponents}. Created {@link TokenStream} instances are
- * never reused.
- *
- * @param fieldName the name of the field the created TokenStream is used for
- * @param reader the reader the streams source reads from
- */
- @Override
- public final TokenStream tokenStream(final String fieldName,
- final Reader reader) {
- return createComponents(fieldName, initReader(reader)).getTokenStream();
- }
-
- /**
- * Override this if you want to add a CharFilter chain.
- */
- protected Reader initReader(Reader reader) {
- return reader;
- }
-
- /**
- * This class encapsulates the outer components of a token stream. It provides
- * access to the source ({@link Tokenizer}) and the outer end (sink), an
- * instance of {@link TokenFilter} which also serves as the
- * {@link TokenStream} returned by
- * {@link Analyzer#tokenStream(String, Reader)} and
- * {@link Analyzer#reusableTokenStream(String, Reader)}.
- */
- public static class TokenStreamComponents {
- protected final Tokenizer source;
- protected final TokenStream sink;
-
- /**
- * Creates a new {@link TokenStreamComponents} instance.
- *
- * @param source
- * the analyzer's tokenizer
- * @param result
- * the analyzer's resulting token stream
- */
- public TokenStreamComponents(final Tokenizer source,
- final TokenStream result) {
- this.source = source;
- this.sink = result;
- }
-
- /**
- * Creates a new {@link TokenStreamComponents} instance.
- *
- * @param source
- * the analyzer's tokenizer
- */
- public TokenStreamComponents(final Tokenizer source) {
- this.source = source;
- this.sink = source;
- }
-
- /**
- * Resets the encapsulated components with the given reader. This method by
- * default returns <code>true</code> indicating that the components have
- * been reset successfully. Subclasses of {@link ReusableAnalyzerBase} might use
- * their own {@link TokenStreamComponents} returning <code>false</code> if
- * the components cannot be reset.
- *
- * @param reader
- * a reader to reset the source component
- * @return <code>true</code> if the components were reset, otherwise
- * <code>false</code>
- * @throws IOException
- * if the component's reset method throws an {@link IOException}
- */
- protected boolean reset(final Reader reader) throws IOException {
- source.reset(reader);
- return true;
- }
-
- /**
- * Returns the sink {@link TokenStream}
- *
- * @return the sink {@link TokenStream}
- */
- protected TokenStream getTokenStream() {
- return sink;
- }
-
- }
-
-}
fnp / pylucene.git / blobdiff