Dev #1
Dev #1
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| final AmazonS3 s3Client = EventHandler.getS3Client(); | ||
| logger.log("Processing Bucket: " + bucketName); | ||
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| ObjectListing files = s3Client.listObjects(bucketName); |
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This code uses an outdated API. ListObjectsV2 is the revised List Objects API, and we recommend you use this revised API for new application developments.
| SalesSystem.orders.put(orderDate, order); | ||
| //Check if the Order entered and present | ||
| if (SalesSystem.orders.containsKey(orderDate)) { | ||
| System.out.println("New order verified to be present in hashmap: " + SalesSystem.orders.get(orderDate)); |
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Problem
You are using a ConcurrentHashMap, but your usage of containsKey() and get() may not be thread-safe at lines: 65 and 66. In between the check and the get() another thread can remove the key and the get() will return null. The remove that can remove the key is at line: 59.
Fix
Consider calling get(), checking instead of your current check if the returned object is null, and then using that object only, without calling get() again.
More info
View an example on GitHub (external link).
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| if (null == lastKnownStatus || lastKnownStatus.getLeft() < timeStamp) { | ||
| lastKnownStatus = new MutablePair<Long, String>(timeStamp, status); | ||
| latestStatusForTrackingNumber.put(trackingNumber, lastKnownStatus); |
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Problem
You are using a ConcurrentHashMap, but your usage of get() and put() may not be thread-safe at lines: 110, 113, 135, and 137. Two threads can perform this same check at the same time and one thread can overwrite the value written by the other thread.
Fix
Consider replacing put() with putIfAbsent() to help prevent accidental overwriting. putIfAbsent() puts the value only if the ConcurrentHashMap does not contain the key and therefore avoids overwriting the value written there by the other thread's putIfAbsent().
More info
putIfAbsent() returns null if the value did not exist and returns the value in the map if one already exists.
View an example on GitHub (external link).
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| public static AmazonS3 getS3Client() { | ||
| return AmazonS3ClientBuilder.standard().withRegion(Regions.DEFAULT_REGION).build(); |
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This code is written so that the client cannot be reused across invocations of the Lambda function.
To improve the performance of the Lambda function, consider using static initialization/constructor, global/static variables and singletons. It allows to keep alive and reuse HTTP connections that were established during a previous invocation.
Learn more about best practices for working with AWS Lambda functions.
| final AmazonS3 s3Client = EventHandler.getS3Client(); | ||
| logger.log("Processing Bucket: " + bucketName); | ||
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| ObjectListing files = s3Client.listObjects(bucketName); |
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This code might not produce accurate results if the operation returns paginated results instead of all results. Consider adding another call to check for additional results.
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| long expirationTime = System.currentTimeMillis() + Duration.ofMinutes(1).toMillis(); | ||
| while(System.currentTimeMillis() < expirationTime) { | ||
| if (s3Client.doesObjectExist(Constants.SUMMARY_BUCKET, summaryUpdateName)) { |
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This code appears to be waiting for a resource before it runs. You could use the waiters feature to help improve efficiency. Consider using ObjectExists or ObjectNotExists. For more information, see https://aws.amazon.com/blogs/developer/waiters-in-the-aws-sdk-for-java/
first pull request