Java tutorial
/* * This file is part of JFlowMap. * * Copyright 2009 Ilya Boyandin * * 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 jflowmap.util; import java.util.Collections; import java.util.Comparator; import java.util.Iterator; import java.util.List; import java.util.regex.Pattern; import com.google.common.base.Predicate; import com.google.common.collect.Iterables; import com.google.common.collect.Lists; /** * @author Ilya Boyandin */ public class CollectionUtils { private CollectionUtils() { } /** * Note: This method makes an in-memory copy of the elements. * This can be inefficient for large lists. */ public static <T> Iterator<T> reverse(Iterator<T> it) { List<T> list = Lists.newArrayList(it); Collections.reverse(list); return list.iterator(); } public static <T> Iterable<T> sort(Iterable<T> items, Comparator<T> comp) { List<T> list = Lists.newArrayList(items); Collections.sort(list, comp); return list; } /** * @param pattern Regular expression */ public static Iterable<String> filterByPattern(Iterable<String> items, final String pattern) { return Iterables.filter(items, new Predicate<String>() { Pattern p = Pattern.compile(pattern); @Override public boolean apply(String attr) { return p.matcher(attr).matches(); } }); } private static final Predicate<Double> PREDICATE_NON_NAN = new Predicate<Double>() { @Override public boolean apply(Double val) { return !val.isNaN(); } }; public static Iterable<Double> removeNaNs(Iterable<Double> values) { return Iterables.filter(values, PREDICATE_NON_NAN); } }