Java tutorial
/* * 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 opennlp.tools.tokenize; import opennlp.tools.util.Span; /** * The interface for tokenizers, which segment a string into its tokens. * <p> * Tokenization is a necessary step before more complex NLP tasks can be applied, * these usually process text on a token level. The quality of tokenization is * important because it influences the performance of high-level task applied to it. * <p> * In segmented languages like English most words are segmented by white spaces * expect for punctuations, etc. which is directly attached to the word without a white space * in between, it is not possible to just split at all punctuations because in abbreviations dots * are a part of the token itself. A tokenizer is now responsible to split these tokens * correctly. * <p> * In non-segmented languages like Chinese tokenization is more difficult since words * are not segmented by a whitespace. * <p> * Tokenizers can also be used to segment already identified tokens further into more * atomic parts to get a deeper understanding. This approach helps more complex task * to gain insight into tokens which do not represent words like numbers, units or tokens * which are part of a special notation. * <p> * For most further task it is desirable to over tokenize rather than under tokenize. */ public interface Tokenizer { /** * Splits a string into its atomic parts * * @param s The string to be tokenized. * @return The String[] with the individual tokens as the array * elements. */ String[] tokenize(String s); /** * Finds the boundaries of atomic parts in a string. * * @param s The string to be tokenized. * @return The Span[] with the spans (offsets into s) for each * token as the individuals array elements. */ Span[] tokenizePos(String s); }