com.yahoo.omid.tso.Bucket.java Source code

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Here is the source code for com.yahoo.omid.tso.Bucket.java

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/**
 * Copyright (c) 2011 Yahoo! 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. See accompanying LICENSE file.
 */

package com.yahoo.omid.tso;

import java.util.BitSet;
import java.util.Set;
import java.util.TreeSet;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

public class Bucket {

    private static final Log LOG = LogFactory.getLog(Bucket.class);

    private static final long BUCKET_SIZE = 32768; // 2 ^ 15

    private BitSet transactions = new BitSet((int) BUCKET_SIZE);

    private int transactionsCommited = 0;
    private int firstUncommited = 0;
    private boolean closed = false;
    private int position;

    public Bucket(int position) {
        this.position = position;
    }

    public boolean isUncommited(long id) {
        return !transactions.get((int) (id % BUCKET_SIZE));
    }

    public Set<Long> abortAllUncommited() {
        Set<Long> result = abortUncommited(BUCKET_SIZE - 1);
        closed = true;
        return result;
    }

    public synchronized Set<Long> abortUncommited(long id) {
        int lastCommited = (int) (id % BUCKET_SIZE);

        Set<Long> aborted = new TreeSet<Long>();
        if (allCommited()) {
            return aborted;
        }

        LOG.trace("Performing scanning...");

        for (int i = transactions.nextClearBit(firstUncommited); i >= 0
                && i <= lastCommited; i = transactions.nextClearBit(i + 1)) {
            aborted.add(((long) position) * BUCKET_SIZE + i);
            commit(i);
        }

        firstUncommited = lastCommited + 1;

        return aborted;
    }

    public synchronized void commit(long id) {
        transactions.set((int) (id % BUCKET_SIZE));
        ++transactionsCommited;
    }

    public boolean allCommited() {
        return BUCKET_SIZE == transactionsCommited || closed;
    }

    public static long getBucketSize() {
        return BUCKET_SIZE;
    }

    public long getFirstUncommitted() {
        return position * BUCKET_SIZE + firstUncommited;
    }

}