net.spy.memcached.PartitionedMap Maven / Gradle / Ivy

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/*
 * arcus-java-client : Arcus Java client
 * Copyright 2010-2014 NAVER Corp.
 *
 * 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 net.spy.memcached;

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

public class PartitionedMap extends AbstractList> {

	private final List> mapList;

	public PartitionedMap(Map map, int size) {
		int expectSize = (map.size() + size - 1) / size;
		int splitBy = size;
		int parsedSize = 0;

		int mapSize = map.size();
		int counter = 0;
		int listIndex = 0;

		mapList = new ArrayList>(expectSize);
		for (int i = 0; i < expectSize; i++) {
			mapList.add(new HashMap());
		}

		for (Map.Entry entry : map.entrySet()) {
			parsedSize++;
			counter++;

			mapList.get(listIndex).put(entry.getKey(), entry.getValue());

			if (parsedSize == splitBy || counter == mapSize) {
				parsedSize = 0;
				listIndex++;
			}
		}
	}

	@Override
	public Map get(int index) {
		int listSize = size();

		if (listSize < 0)
			throw new IllegalArgumentException("negative size: " + listSize);
	
		if (index < 0)
			throw new IndexOutOfBoundsException("index " + index
					+ " must not be negative");
		
		if (index >= listSize)
			throw new IndexOutOfBoundsException("index " + index
					+ " must be less than size " + listSize);

		return mapList.get(index);
	}

	@Override
	public int size() {
		return mapList.size();
	}

	@Override
	public boolean isEmpty() {
		return mapList.isEmpty();
	}
}