Java tutorial
/* * Copyright (C) 2013-2016 52North Initiative for Geospatial Open Source * Software GmbH * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 as published * by the Free Software Foundation. * * If the program is linked with libraries which are licensed under one of * the following licenses, the combination of the program with the linked * library is not considered a "derivative work" of the program: * * - Apache License, version 2.0 * - Apache Software License, version 1.0 * - GNU Lesser General Public License, version 3 * - Mozilla Public License, versions 1.0, 1.1 and 2.0 * - Common Development and Distribution License (CDDL), version 1.0 * * Therefore the distribution of the program linked with libraries licensed * under the aforementioned licenses, is permitted by the copyright holders * if the distribution is compliant with both the GNU General Public License * version 2 and the aforementioned licenses. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * for more details. */ package org.n52.io.response; import java.text.Collator; import java.util.ArrayList; import java.util.Arrays; import java.util.Collection; import java.util.Collections; import java.util.Comparator; import java.util.Iterator; import java.util.List; import com.fasterxml.jackson.annotation.JsonIgnore; public abstract class OutputCollection<T> implements Iterable<T> { private final List<T> items; protected OutputCollection() { this.items = new ArrayList<>(); } protected OutputCollection(T item) { this(); if (item != null) { addItem(item); } } protected OutputCollection(Collection<T> items) { this.items = items == null ? new ArrayList<T>() : new ArrayList<>(items); } protected OutputCollection(T... items) { this.items = items == null ? new ArrayList<T>() : Arrays.asList(items); } @JsonIgnore public boolean isEmpty() { return items.isEmpty(); } public final void addItem(T item) { items.add(item); } public final void addItems(Collection<T> items) { this.items.addAll(items); } public void removeItem(T item) { items.remove(item); } public T getItem(int i) { return items.get(i); } public List<T> getItems() { return Collections.unmodifiableList(items); } public int size() { return items.size(); } public OutputCollection<T> withSortedItems() { Collections.sort(items, getComparator()); return this; } public OutputCollection<T> withSortedItems(Collator collator) { return collator != null && isCollatorComparable() ? collatorSort(collator) : withSortedItems(); } private OutputCollection<T> collatorSort(Collator collator) { for (int i = 0; i < items.size(); i++) { for (int j = i + 1; j < items.size(); j++) { CollatorComparable<T> first = (CollatorComparable<T>) items; T second = items.get(j); if (first.compare(collator, second) > 0) { swap(i, j); } } } return this; } private boolean isCollatorComparable() { return CollatorComparable.class.isAssignableFrom(items.getClass()); } private void swap(int i, int j) { T tmp = items.get(i); items.add(i, items.get(j)); items.add(j, tmp); } protected abstract Comparator<T> getComparator(); public boolean containsItem(T item) { return items.contains(item); } @Override public Iterator<T> iterator() { return items.iterator(); } }