org.obm.push.utils.ShareAmount.java Source code

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Here is the source code for org.obm.push.utils.ShareAmount.java

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/* ***** BEGIN LICENSE BLOCK *****
 * 
 * Copyright (C) 2014 Linagora
 *
 * This program is free software: you can redistribute it and/or 
 * modify it under the terms of the GNU Affero General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version, provided you comply 
 * with the Additional Terms applicable for OBM connector by Linagora 
 * pursuant to Section 7 of the GNU Affero General Public License, 
 * subsections (b), (c), and (e), pursuant to which you must notably (i) retain 
 * the Message sent thanks to OBM, Free Communication by Linagora? 
 * signature notice appended to any and all outbound messages 
 * (notably e-mail and meeting requests), (ii) retain all hypertext links between 
 * OBM and obm.org, as well as between Linagora and linagora.com, and (iii) refrain 
 * from infringing Linagora intellectual property rights over its trademarks 
 * and commercial brands. Other Additional Terms apply, 
 * see <http://www.linagora.com/licenses/> for more details. 
 *
 * 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 Affero General Public License 
 * for more details. 
 *
 * You should have received a copy of the GNU Affero General Public License 
 * and its applicable Additional Terms for OBM along with this program. If not, 
 * see <http://www.gnu.org/licenses/> for the GNU Affero General Public License version 3 
 * and <http://www.linagora.com/licenses/> for the Additional Terms applicable to 
 * OBM connectors. 
 * 
 * ***** END LICENSE BLOCK ***** */
package org.obm.push.utils;

import java.util.Collection;
import java.util.Map;

import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.Maps;

public class ShareAmount<T> {

    private Collection<T> entries;

    public static <T> ShareAmount<T> forEntries(Collection<T> entries) {
        Preconditions.checkNotNull(entries);
        Preconditions.checkArgument(!entries.isEmpty());
        return new ShareAmount<T>(entries);
    }

    private ShareAmount(Collection<T> entries) {
        this.entries = entries;
    }

    public Map<T, Integer> amount(final int amount) {
        return Maps.newHashMap(Maps.toMap(entries, new Function<T, Integer>() {
            int amountLeft = amount;
            int entriesLeft = entries.size();

            @Override
            public Integer apply(T entry) {
                try {
                    int ceiledAverage = ceiledAverage(amountLeft, entriesLeft);
                    if (amountLeft >= ceiledAverage) {
                        amountLeft -= ceiledAverage;
                        return ceiledAverage;
                    } else {
                        int returnValue = amountLeft;
                        amountLeft = 0;
                        return returnValue;
                    }
                } finally {
                    entriesLeft--;
                }
            }
        }));
    }

    private int ceiledAverage(int amount, int entriesCount) {
        return Double.valueOf(Math.ceil(Double.valueOf(amount) / entriesCount)).intValue();
    }
}