Java tutorial
/******************************************************************************* * Copyright 2015 * Ubiquitous Knowledge Processing (UKP) Lab * Technische Universitt Darmstadt * * Licensed 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 de.tudarmstadt.ukp.dkpro.wsd; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.StringReader; import java.lang.reflect.Constructor; import java.net.URL; import java.util.HashMap; import java.util.Map; import org.apache.commons.io.IOUtils; import com.google.common.collect.HashMultimap; import com.google.common.collect.Multimap; /** * I/O utilities for WSD * * @author Tristan Miller <miller@ukp.informatik.tu-darmstadt.de> */ public class WSDUtils { /** * Read key-value pairs of the specified types from the specified columns of * a whitespace-delimited text file into a Map. * * @param url * Location of the file to read * @param keyColumn * The index of the column giving the keys * @param keyClass * The class of the key * @param valueColumn * The index of the column giving the values * @param valueClass * The class of the value * @return A map of keys to values * @throws IOException * @throws IllegalArgumentException */ public static <K, V> Map<K, V> readMap(final URL url, final int keyColumn, final Class<K> keyClass, final int valueColumn, final Class<V> valueClass) throws IOException, IllegalArgumentException { return readMap(url, keyColumn, keyClass, valueColumn, valueClass, "[ \\t]+"); } /** * Read key-value pairs of the specified types from the specified columns of * a delimited text file into a Map. * * @param url * Location of the file to read * @param keyColumn * The index of the column giving the keys * @param keyClass * The class of the key * @param valueColumn * The index of the column giving the values * @param valueClass * The class of the value * @param delimiterRegex * A regular expression for the field delimiter * @return A map of keys to values * @throws IOException * @throws IllegalArgumentException */ public static <K, V> Map<K, V> readMap(final URL url, final int keyColumn, final Class<K> keyClass, final int valueColumn, final Class<V> valueClass, final String delimiterRegex) throws IOException, IllegalArgumentException { Map<K, V> map = new HashMap<K, V>(); InputStream is = url.openStream(); String content = IOUtils.toString(is, "UTF-8"); BufferedReader br = new BufferedReader(new StringReader(content)); Constructor<K> keyConstructor; Constructor<V> valueConstructor; try { keyConstructor = keyClass.getConstructor(String.class); valueConstructor = valueClass.getConstructor(String.class); } catch (Exception e) { throw new IllegalArgumentException(e); } String line; String[] lineParts; while ((line = br.readLine()) != null) { lineParts = line.split(delimiterRegex); K key; V value; try { key = keyConstructor.newInstance(lineParts[keyColumn - 1]); value = valueConstructor.newInstance(lineParts[valueColumn - 1]); } catch (Exception e) { throw new IllegalArgumentException(e); } map.put(key, value); } return map; } /** * Read key-value pairs of the specified types from the specified columns of * a whitespace-delimited text file into a Multimap. * * @param url * Location of the file to read * @param keyColumn * The index of the column giving the keys * @param keyClass * The class of the key * @param valueColumn * The index of the column giving the values * @param valueClass * The class of the value * @return A map of keys to values * @throws IOException * @throws IllegalArgumentException */ public static <K, V> Multimap<K, V> readMultimap(final URL url, final int keyColumn, final Class<K> keyClass, final int valueColumn, final Class<V> valueClass) throws IOException, IllegalArgumentException { return readMultimap(url, keyColumn, keyClass, valueColumn, valueClass, "[ \\t]+"); } /** * Read key-value pairs of the specified types from the specified columns of * a delimited text file into a Multimap. * * @param url * Location of the file to read * @param keyColumn * The index of the column giving the keys * @param keyClass * The class of the key * @param valueColumn * The index of the column giving the values * @param valueClass * The class of the value * @param delimiterRegex * A regular expression for the field delimiter * @return A map of keys to values * @throws IOException * @throws IllegalArgumentException */ public static <K, V> Multimap<K, V> readMultimap(final URL url, final int keyColumn, final Class<K> keyClass, final int valueColumn, final Class<V> valueClass, final String delimiterRegex) throws IOException, IllegalArgumentException { Multimap<K, V> map = HashMultimap.create(); InputStream is = url.openStream(); String content = IOUtils.toString(is, "UTF-8"); BufferedReader br = new BufferedReader(new StringReader(content)); Constructor<K> keyConstructor; Constructor<V> valueConstructor; try { keyConstructor = keyClass.getConstructor(String.class); valueConstructor = valueClass.getConstructor(String.class); } catch (Exception e) { throw new IllegalArgumentException(e); } String line; String[] lineParts; while ((line = br.readLine()) != null) { lineParts = line.split(delimiterRegex); K key; V value; try { key = keyConstructor.newInstance(lineParts[keyColumn - 1]); value = valueConstructor.newInstance(lineParts[valueColumn - 1]); } catch (Exception e) { throw new IllegalArgumentException(e); } map.put(key, value); } return map; } /** * Truncate a string to a given length * * @param string * @param length * @return */ public static String truncate(String string, int length) { if (string == null) { return null; } if (string.length() <= length) { return new String(string); } return string.substring(0, length) + ""; } }