1 package org.apache.lucene.analysis; 2 3 /** 4 * Copyright 2004 The Apache Software Foundation 5 * 6 * Licensed under the Apache License, Version 2.0 (the "License"); 7 * you may not use this file except in compliance with the License. 8 * You may obtain a copy of the License at 9 * 10 * http://www.apache.org/licenses/LICENSE-2.0 11 * 12 * Unless required by applicable law or agreed to in writing, software 13 * distributed under the License is distributed on an "AS IS" BASIS, 14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 * See the License for the specific language governing permissions and 16 * limitations under the License. 17 */ 18 19 import java.io.IOException; 20 21 /** A TokenStream enumerates the sequence of tokens, either from 22 fields of a document or from query text. 23 <p> 24 This is an abstract class. Concrete subclasses are: 25 <ul> 26 <li>{@link Tokenizer}, a TokenStream 27 whose input is a Reader; and 28 <li>{@link TokenFilter}, a TokenStream 29 whose input is another TokenStream. 30 </ul> 31 */ 32 33 public abstract class TokenStream { 34 /** Returns the next token in the stream, or null at EOS. */ 35 public abstract Token next() throws IOException; 36 37 /** Releases resources associated with this stream. */ 38 public void close() throws IOException {} 39 } 40