com.hazelcast.map.impl.nearcache.KeyStateMarkerImpl Maven / Gradle / Ivy

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/*
 * Copyright (c) 2008-2016, Hazelcast, Inc. All Rights Reserved.
 *
 * 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.hazelcast.map.impl.nearcache;

import com.hazelcast.nio.serialization.Data;

import java.util.concurrent.atomic.AtomicLongArray;

import static com.hazelcast.map.impl.nearcache.KeyStateMarker.STATE.MARKED;
import static com.hazelcast.map.impl.nearcache.KeyStateMarker.STATE.REMOVED;
import static com.hazelcast.map.impl.nearcache.KeyStateMarker.STATE.UNMARKED;
import static com.hazelcast.util.HashUtil.hashToIndex;

public class KeyStateMarkerImpl implements KeyStateMarker {

    private final int markCount;
    private volatile AtomicLongArray marks;

    public KeyStateMarkerImpl(int markCount) {
        this.markCount = markCount;
        this.marks = new AtomicLongArray(markCount);
    }

    @Override
    public boolean tryMark(Object key) {
        return casState(key, UNMARKED, MARKED);
    }

    @Override
    public boolean tryUnmark(Object key) {
        return casState(key, MARKED, UNMARKED);
    }

    @Override
    public boolean tryRemove(Object key) {
        return casState(key, MARKED, REMOVED);
    }

    @Override
    public void forceUnmark(Object key) {
        int slot = getSlot(key);
        marks.set(slot, UNMARKED.getState());
    }

    @Override
    public void init() {
        marks = new AtomicLongArray(markCount);
    }

    private boolean casState(Object key, STATE expect, STATE update) {
        int slot = getSlot(key);
        return marks.compareAndSet(slot, expect.getState(), update.getState());
    }

    private int getSlot(Object key) {
        int hash = key instanceof Data ? ((Data) key).getPartitionHash() : key.hashCode();
        return hashToIndex(hash, markCount);
    }
}