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Rapidoid Commons

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package org.rapidoid.util;

import org.rapidoid.RapidoidThing;
import org.rapidoid.annotation.Authors;
import org.rapidoid.annotation.Since;

/*
 * #%L
 * rapidoid-commons
 * %%
 * Copyright (C) 2014 - 2016 Nikolche Mihajlovski and contributors
 * %%
 * 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.
 * #L%
 */

@Authors("Nikolche Mihajlovski")
@Since("2.0.0")
public class SimpleHashTable extends RapidoidThing {

	protected static final int DEFAULT_BUCKET_SIZE = 5;

	public final SimpleList[] buckets;

	public SimpleHashTable(int width) {
		this(width, DEFAULT_BUCKET_SIZE);
	}

	@SuppressWarnings("unchecked")
	public SimpleHashTable(int width, int initialBucketSize) {
		this.buckets = new SimpleList[width];
		for (int i = 0; i < buckets.length; i++) {
			buckets[i] = newList(initialBucketSize);
		}
	}

	protected SimpleList newList(int initialBucketSize) {
		return new SimpleList(initialBucketSize);
	}

	public void put(long key, T value) {
		bucket(key).add(value);
	}

	public SimpleList bucket(long key) {
		int index = index(key);
		return getBucket(index);
	}

	protected SimpleList getBucket(int index) {
		SimpleList list;

		// after construction, other threads might need some time to see the new references
		while ((list = buckets[index]) == null) {
		}

		return list;
	}

	public int index(long key) {
		return (int) (Math.abs(key) % buckets.length);
	}

	public void clear() {
		for (int i = 0; i < buckets.length; i++) {
			clearBucket(i);
		}
	}

	protected void clearBucket(int index) {
		getBucket(index).clear();
	}

}