com.yusufaytas.dlock.spring.IntervalLockRegistrar Maven / Gradle / Ivy

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/**
 * Copyright © 2018 Yusuf Aytas. 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.yusufaytas.dlock.spring;


import com.yusufaytas.dlock.TryLock;
import com.yusufaytas.dlock.core.IntervalLock;
import com.yusufaytas.dlock.core.LockConfig;
import com.yusufaytas.dlock.core.LockRegistry;
import com.yusufaytas.dlock.core.UnreachableLockException;
import java.lang.reflect.Method;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.util.Optional;
import org.aspectj.lang.ProceedingJoinPoint;
import org.aspectj.lang.annotation.Around;
import org.aspectj.lang.annotation.Aspect;
import org.aspectj.lang.reflect.MethodSignature;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.stereotype.Component;
import org.springframework.util.StringUtils;

@Aspect
@Component
public class IntervalLockRegistrar {

  private final static Logger logger = LoggerFactory.getLogger(IntervalLockRegistrar.class);
  private final static String LOCK_OWNER_PROPERTY_NAME = "com.yusufaytas.dlock.owner";

  @Autowired
  private Environment env;

  @Autowired(required = false)
  public IntervalLockRegistrar(IntervalLock intervalLock) {
    if (intervalLock == null) {
      logger.warn("Couldn't find any IntervalLock bean to register.");
      return;
    }
    LockRegistry.setLock(intervalLock);
  }

  @Around("@annotation(com.yusufaytas.dlock.TryLock)")
  public void tryLock(ProceedingJoinPoint joinPoint)
      throws Throwable {
    MethodSignature signature = (MethodSignature) joinPoint.getSignature();
    Method method = signature.getMethod();
    TryLock tryLock = method.getAnnotation(TryLock.class);

    if (shouldProceed(tryLock)) {
      joinPoint.proceed();
    }
  }

  private boolean shouldProceed(TryLock tryLock) {
    try {
      Optional lock = LockRegistry.getLock();
      if (!lock.isPresent()) {
        return true;
      }
      LockConfig config = getLockConfigWithDefaults(tryLock);
      return lock.get().tryLock(config);
    } catch (UnreachableLockException e) {
      logger.error("Couldn't lock due to lock provider", e);
      return false;
    }
  }

  private LockConfig getLockConfigWithDefaults(TryLock tryLock) {
    String owner = env.getProperty(tryLock.owner(), tryLock.owner());
    if (StringUtils.isEmpty(owner)) {
      owner = env.getProperty(LOCK_OWNER_PROPERTY_NAME, getHostname());
    }
    return new LockConfig(tryLock.name(), owner, tryLock.lockFor());
  }

  private String getHostname() {
    try {
      return InetAddress.getLocalHost().getHostName();
    } catch (UnknownHostException e) {
      return "";
    }
  }
}