/*
 * 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.facebook.presto.spi.block;

import java.util.Objects;
import java.util.UUID;
import java.util.concurrent.atomic.AtomicLong;

public class DictionaryId
{
    private static final UUID nodeId = UUID.randomUUID();
    private static final AtomicLong sequenceGenerator = new AtomicLong();

    private final long mostSignificantBits;
    private final long leastSignificantBits;
    private final long sequenceId;

    public static DictionaryId randomDictionaryId()
    {
        return new DictionaryId(nodeId.getMostSignificantBits(), nodeId.getLeastSignificantBits(), sequenceGenerator.getAndIncrement());
    }

    public DictionaryId(long mostSignificantBits, long leastSignificantBits, long sequenceId)
    {
        this.mostSignificantBits = mostSignificantBits;
        this.leastSignificantBits = leastSignificantBits;
        this.sequenceId = sequenceId;
    }

    public long getMostSignificantBits()
    {
        return mostSignificantBits;
    }

    public long getLeastSignificantBits()
    {
        return leastSignificantBits;
    }

    public long getSequenceId()
    {
        return sequenceId;
    }

    @Override
    public boolean equals(Object o)
    {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        DictionaryId that = (DictionaryId) o;
        return mostSignificantBits == that.mostSignificantBits &&
                leastSignificantBits == that.leastSignificantBits &&
                sequenceId == that.sequenceId;
    }

    @Override
    public int hashCode()
    {
        return Objects.hash(mostSignificantBits, leastSignificantBits, sequenceId);
    }
}