com.xiongyingqi.common.utils.concurrent.LockSupport Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of simplify-commons Show documentation

common utils.

The newest version!

package com.xiongyingqi.common.utils.concurrent;

import java.util.concurrent.locks.ReentrantLock;

/**
 * @author xiongyingqi
 * @since 20170802
 */
public class LockSupport {
  private ReentrantLock[] reentrantLock;
  private int lockSize;

  private LockSupport(int lockSize) {
    this.lockSize = lockSize;
    reentrantLock = new ReentrantLock[lockSize];
    for (int i = 0; i < lockSize; i++) {
      reentrantLock[i] = new ReentrantLock();
    }
  }

  public static LockSupport newInstance(int lockSize) {
    return new LockSupport(lockSize);
  }

  public ReentrantLock getLock(Object object) {
    if (object == null) {
      throw new NullPointerException("Lock object is null!");
    }
    int hash = hash(object);
    ReentrantLock reentrantLock = lockForHash(hash);
    return reentrantLock;
  }

  private ReentrantLock lockForHash(int hash) {
    hash &= Integer.MAX_VALUE;
    int index = hash % lockSize;
    return reentrantLock[index];
  }

  private static int hash(Object object) {
    int h = object.hashCode();

    // Spread bits to regularize both segment and index locations,
    // using variant of single-word Wang/Jenkins hash.
    h += (h << 15) ^ 0xffffcd7d;
    h ^= (h >>> 10);
    h += (h << 3);
    h ^= (h >>> 6);
    h += (h << 2) + (h << 14);
    return h ^ (h >>> 16);
  }

}