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Lucene example source code file (Analyzer.java)
The Lucene Analyzer.java source codepackage org.apache.lucene.analysis; /** * 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. */ import java.io.Reader; import java.io.IOException; import java.io.Closeable; import java.lang.reflect.Modifier; import org.apache.lucene.util.CloseableThreadLocal; import org.apache.lucene.store.AlreadyClosedException; import org.apache.lucene.document.Fieldable; /** An Analyzer builds TokenStreams, which analyze text. It thus represents a * policy for extracting index terms from text. * <p> * Typical implementations first build a Tokenizer, which breaks the stream of * characters from the Reader into raw Tokens. One or more TokenFilters may * then be applied to the output of the Tokenizer. * <p>The {@code Analyzer}-API in Lucene is based on the decorator pattern. * Therefore all non-abstract subclasses must be final or their {@link #tokenStream} * and {@link #reusableTokenStream} implementations must be final! This is checked * when Java assertions are enabled. */ public abstract class Analyzer implements Closeable { protected Analyzer() { super(); assert assertFinal(); } private boolean assertFinal() { try { final Class<?> clazz = getClass(); assert clazz.isAnonymousClass() || (clazz.getModifiers() & (Modifier.FINAL | Modifier.PRIVATE)) != 0 || ( Modifier.isFinal(clazz.getMethod("tokenStream", String.class, Reader.class).getModifiers()) && Modifier.isFinal(clazz.getMethod("reusableTokenStream", String.class, Reader.class).getModifiers()) ) : "Analyzer implementation classes or at least their tokenStream() and reusableTokenStream() implementations must be final"; return true; } catch (NoSuchMethodException nsme) { return false; } } /** Creates a TokenStream which tokenizes all the text in the provided * Reader. Must be able to handle null field name for * backward compatibility. */ public abstract TokenStream tokenStream(String fieldName, Reader reader); /** Creates a TokenStream that is allowed to be re-used * from the previous time that the same thread called * this method. Callers that do not need to use more * than one TokenStream at the same time from this * analyzer should use this method for better * performance. */ public TokenStream reusableTokenStream(String fieldName, Reader reader) throws IOException { return tokenStream(fieldName, reader); } private CloseableThreadLocal<Object> tokenStreams = new CloseableThreadLocal |
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