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/*
* Copyright (C) 2014 The CyanogenMod Project
*
* 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 com.cyanogenmod.eleven.utils;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.TreeMap;
/**
* Implementation of custom sorting routines of song list
*/
public class SortUtils {
/**
* Sorts items based on the localized bucket letter they belong to and the sort order specified
* @param items the original list of items
* @param sortOrder values derived from SortOrder.class
* @return the new sorted list
*/
public static <T> ArrayList<T> localizeSortList(ArrayList<T> items, String sortOrder) {
ArrayList<T> finalList = Lists.newArrayList();
// map of items grouped by their localized label
TreeMap<String, LinkedList<T>> mappedList = new TreeMap<String, LinkedList<T>>();
// list holding items that don't have a localized label
ArrayList<T> nonLocalizableItems = Lists.newArrayList();
for (T item : items) {
// get the bucket letter based on the attribute to sort by
String label = MusicUtils.getLocalizedBucketLetterByAttribute(item, sortOrder);
//divvy items based on their localized bucket letter
if (label != null) {
if (mappedList.get(label) == null) {
// create new label slot to assign items
mappedList.put(label, Lists.<T>newLinkedList());
}
// add item to the label's list
mappedList.get(label).add(item);
} else {
nonLocalizableItems.add(item);
}
}
// generate a sorted item list out of localizable items
boolean isDescendingSort = MusicUtils.isSortOrderDesending(sortOrder);
finalList.addAll(getSortedList(mappedList, isDescendingSort));
finalList.addAll(nonLocalizableItems);
return finalList;
}
/**
* Traverses a tree map of a divvied up list to generate a sorted list
* @param mappedList the bucketized list of items based on the header
* @param reverseOrder dictates the order in which the TreeMap is traversed (descending order
* if true)
* @return the combined sorted list
*/
private static <T> ArrayList<T> getSortedList(TreeMap<String, LinkedList<T>> mappedList,
boolean reverseOrder) {
ArrayList<T> sortedList = Lists.newArrayList();
Iterator<String> iterator = mappedList.navigableKeySet().iterator();
if (reverseOrder) {
iterator = mappedList.navigableKeySet().descendingIterator();
}
while (iterator.hasNext()) {
LinkedList<T> list = mappedList.get(iterator.next());
sortedList.addAll(list);
}
return sortedList;
}
}
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