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fix: Version number pattern update overwritten #2968 (#2980)

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* Fix bug #2968

* Fix bug #2968
This commit is contained in:
Avinash Shukla
2024-06-02 19:23:15 +05:30
committed by GitHub
parent d4b0f3db8d
commit dd38bd3ffb
1 changed files with 18 additions and 15 deletions
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version-number/src/main/java/com/iluwatar/versionnumber/BookRepository.java
+18 -15
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@@ -24,8 +24,7 @@
*/
package com.iluwatar.versionnumber;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* This repository represents simplified database.
@@ -34,7 +33,8 @@ import java.util.Map;
* as much as in real databases.
*/
public class BookRepository {
private final Map<Long, Book> collection = new HashMap<>();
private final ConcurrentHashMap<Long, Book> collection = new ConcurrentHashMap<>();
private final Object lock = new Object();
/**
* Adds book to collection.
@@ -57,19 +57,22 @@ public class BookRepository {
throw new BookNotFoundException("Not found book with id: " + book.getId());
}
var latestBook = collection.get(book.getId());
if (book.getVersion() != latestBook.getVersion()) {
throw new VersionMismatchException(
"Tried to update stale version " + book.getVersion()
+ " while actual version is " + latestBook.getVersion()
);
// used synchronized block to ensure only one thread compares and update the version
synchronized (lock) {
var latestBook = collection.get(book.getId());
if (book.getVersion() != latestBook.getVersion()) {
throw new VersionMismatchException(
"Tried to update stale version " + book.getVersion()
+ " while actual version is " + latestBook.getVersion()
);
}
// update version, including client representation - modify by reference here
book.setVersion(book.getVersion() + 1);
// save book copy to repository
collection.put(book.getId(), new Book(book));
}
// update version, including client representation - modify by reference here
book.setVersion(book.getVersion() + 1);
// save book copy to repository
collection.put(book.getId(), new Book(book));
}
/**