org.n52.io.response.OutputCollection Maven / Gradle / Ivy

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/*
 * Copyright (C) 2013-2019 52°North 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 java.util.stream.Stream;

import com.fasterxml.jackson.annotation.JsonIgnore;

public abstract class OutputCollection implements Iterable {

    private final List items;

    protected OutputCollection() {
        this.items = new ArrayList<>();
    }

    protected OutputCollection(T item) {
        this();
        if (item != null) {
            addItem(item);
        }
    }

    protected OutputCollection(Collection items) {
        this.items = items == null
                ? new ArrayList<>(0)
                : new ArrayList<>(items);
    }

    @SafeVarargs
    protected OutputCollection(T... items) {
        this.items = items == null
                ? new ArrayList<>(0)
                : Arrays.asList(items);
    }

    @JsonIgnore
    public boolean isEmpty() {
        return items.isEmpty();
    }

    public final void addItem(T item) {
        items.add(item);
    }

    public final void addItems(Collection toAdd) {
        this.items.addAll(toAdd);
    }

    public void removeItem(T item) {
        items.remove(item);
    }

    public T getItem(int i) {
        return items.get(i);
    }

    public List getItems() {
        return Collections.unmodifiableList(items);
    }

    public int size() {
        return items.size();
    }

    public OutputCollection withSortedItems() {
        Collections.sort(items, getComparator());
        return this;
    }

    public OutputCollection withSortedItems(Collator collator) {
        return collator != null && isCollatorComparable()
                ? collatorSort(collator)
                : withSortedItems();
    }

    private OutputCollection collatorSort(Collator collator) {
        for (int i = 0; i < items.size(); i++) {
            for (int j = i + 1; j < items.size(); j++) {
                @SuppressWarnings("unchecked")
                CollatorComparable first = (CollatorComparable) items;
                T second = items.get(j);
                if (first.compare(collator, second) > 0) {
                    swap(i, j);
                }
            }
        }
        return this;
    }

    private boolean isCollatorComparable() {
        //FIXME this is NEVER true
        return items instanceof CollatorComparable;
    }

    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 getComparator();

    public boolean containsItem(T item) {
        return items.contains(item);
    }

    public Stream stream() {
        return items.stream();
    }

    @Override
    public Iterator iterator() {
        return items.iterator();
    }

}