fm.last.lastfmlive.data.Chart.java Source code

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Here is the source code for fm.last.lastfmlive.data.Chart.java

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/*
 * Copyright 2012 Last.fm
 *
 *  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 fm.last.lastfmlive.data;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import com.google.common.collect.Ordering;

public class Chart<T> {
    public static final class ChartEntry<E> {
        private final E item;
        private final int weight;

        public E getItem() {
            return item;
        }

        public int getWeight() {
            return weight;
        }

        public ChartEntry(E item, int weight) {
            this.item = item;
            this.weight = weight;
        }

    }

    private final HashMap<T, Integer> artistCountMap;

    public Chart() {
        artistCountMap = new HashMap<T, Integer>();
    }

    public void putAll(List<ChartEntry<T>> entries) {
        for (ChartEntry<T> entry : entries) {
            put(entry.item, entry.weight);
        }
    }

    public void put(T item, int weight) {
        if (artistCountMap.containsKey(item)) {
            artistCountMap.put(item, artistCountMap.get(item) + weight);
        } else {
            artistCountMap.put(item, weight);
        }
    }

    public List<T> sortedView() {
        Ordering<Map.Entry<T, Integer>> ordering = new Ordering<Map.Entry<T, Integer>>() {
            @Override
            public int compare(java.util.Map.Entry<T, Integer> arg0, java.util.Map.Entry<T, Integer> arg1) {
                return arg0.getValue().compareTo(arg1.getValue());
            }
        };
        return Lists.transform(ordering.reverse().sortedCopy(artistCountMap.entrySet()),
                new Function<Map.Entry<T, Integer>, T>() {
                    public T apply(Entry<T, Integer> arg0) {
                        return arg0.getKey();
                    }
                });
    }

    public static <E> List<ChartEntry<E>> autoWeight(List<E> items) {
        List<ChartEntry<E>> entries = new ArrayList<ChartEntry<E>>();
        int i = 0;
        int len = items.size();
        for (E a : items) {
            entries.add(new ChartEntry<E>(a, len - i));
            i++;
        }
        return entries;
    }

}