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Fixes according PR comments. Mainly Readme edits.
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‎caching/README.md

Lines changed: 66 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -43,39 +43,29 @@ Wikipedia says:
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**Programmatic Example**
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Let's first look at the data layer of our application. The interesting classes are `UserAccount`
46-
which is a simple Java object containing the user account details, and `DbManager` which handles
47-
reading and writing of these objects to/from MongoDB database.
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which is a simple Java object containing the user account details, and `DbManager` interface which handles
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reading and writing of these objects to/from database.
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```java
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@Setter
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@Getter
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@Data
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@AllArgsConstructor
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@ToString
53+
@EqualsAndHashCode
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public class UserAccount {
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private String userId;
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private String userName;
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private String additionalInfo;
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}
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60-
@Slf4j
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public final class DbManager {
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private static MongoClient mongoClient;
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private static MongoDatabase db;
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private DbManager() { /*...*/ }
67-
68-
public static void createVirtualDb() { /*...*/ }
69-
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public static void connect() throws ParseException { /*...*/ }
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public static UserAccount readFromDb(String userId) { /*...*/ }
60+
public interface DbManager {
7361

74-
public static void writeToDb(UserAccount userAccount) { /*...*/ }
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public static void updateDb(UserAccount userAccount) { /*...*/ }
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78-
public static void upsertDb(UserAccount userAccount) { /*...*/ }
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void connect();
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void disconnect();
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65+
UserAccount readFromDb(String userId);
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UserAccount writeToDb(UserAccount userAccount);
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UserAccount updateDb(UserAccount userAccount);
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UserAccount upsertDb(UserAccount userAccount);
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}
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```
8171

@@ -171,30 +161,43 @@ strategies.
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@Slf4j
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public class CacheStore {
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private static final int CAPACITY = 3;
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private static LruCache cache;
166+
private final DbManager dbManager;
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/* ... details omitted ... */
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178-
public static UserAccount readThrough(String userId) {
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public UserAccount readThrough(final String userId) {
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if (cache.contains(userId)) {
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LOGGER.info("# Cache Hit!");
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LOGGER.info("# Found in Cache!");
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return cache.get(userId);
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}
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LOGGER.info("# Cache Miss!");
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UserAccount userAccount = DbManager.readFromDb(userId);
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LOGGER.info("# Not found in cache! Go to DB!!");
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UserAccount userAccount = dbManager.readFromDb(userId);
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cache.set(userId, userAccount);
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return userAccount;
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}
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189-
public static void writeThrough(UserAccount userAccount) {
181+
public void writeThrough(final UserAccount userAccount) {
190182
if (cache.contains(userAccount.getUserId())) {
191-
DbManager.updateDb(userAccount);
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dbManager.updateDb(userAccount);
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} else {
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DbManager.writeToDb(userAccount);
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dbManager.writeToDb(userAccount);
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}
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cache.set(userAccount.getUserId(), userAccount);
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}
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190+
public void writeAround(final UserAccount userAccount) {
191+
if (cache.contains(userAccount.getUserId())) {
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dbManager.updateDb(userAccount);
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// Cache data has been updated -- remove older
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cache.invalidate(userAccount.getUserId());
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// version from cache.
196+
} else {
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dbManager.writeToDb(userAccount);
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}
199+
}
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public static void clearCache() {
199202
if (cache != null) {
200203
cache.clear();
@@ -225,34 +228,39 @@ class.
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public final class AppManager {
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private static CachingPolicy cachingPolicy;
231+
private final DbManager dbManager;
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private final CacheStore cacheStore;
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private AppManager() {
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}
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232-
public static void initDb(boolean useMongoDb) { /* ... */ }
237+
public void initDb() { /* ... */ }
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public static void initCachingPolicy(CachingPolicy policy) { /* ... */ }
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public static void initCacheCapacity(int capacity) { /* ... */ }
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public static UserAccount find(String userId) {
239-
if (cachingPolicy == CachingPolicy.THROUGH || cachingPolicy == CachingPolicy.AROUND) {
240-
return CacheStore.readThrough(userId);
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public UserAccount find(final String userId) {
244+
LOGGER.info("Trying to find {} in cache", userId);
245+
if (cachingPolicy == CachingPolicy.THROUGH
246+
|| cachingPolicy == CachingPolicy.AROUND) {
247+
return cacheStore.readThrough(userId);
241248
} else if (cachingPolicy == CachingPolicy.BEHIND) {
242-
return CacheStore.readThroughWithWriteBackPolicy(userId);
249+
return cacheStore.readThroughWithWriteBackPolicy(userId);
243250
} else if (cachingPolicy == CachingPolicy.ASIDE) {
244251
return findAside(userId);
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}
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return null;
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}
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249-
public static void save(UserAccount userAccount) {
256+
public void save(final UserAccount userAccount) {
257+
LOGGER.info("Save record!");
250258
if (cachingPolicy == CachingPolicy.THROUGH) {
251-
CacheStore.writeThrough(userAccount);
259+
cacheStore.writeThrough(userAccount);
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} else if (cachingPolicy == CachingPolicy.AROUND) {
253-
CacheStore.writeAround(userAccount);
261+
cacheStore.writeAround(userAccount);
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} else if (cachingPolicy == CachingPolicy.BEHIND) {
255-
CacheStore.writeBehind(userAccount);
263+
cacheStore.writeBehind(userAccount);
256264
} else if (cachingPolicy == CachingPolicy.ASIDE) {
257265
saveAside(userAccount);
258266
}
@@ -272,24 +280,35 @@ Here is what we do in the main class of the application.
272280
@Slf4j
273281
public class App {
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275-
public static void main(String[] args) {
276-
AppManager.initDb(false);
277-
AppManager.initCacheCapacity(3);
278-
var app = new App();
283+
public static void main(final String[] args) {
284+
boolean isDbMongo = isDbMongo(args);
285+
if(isDbMongo){
286+
LOGGER.info("Using the Mongo database engine to run the application.");
287+
} else {
288+
LOGGER.info("Using the 'in Memory' database to run the application.");
289+
}
290+
App app = new App(isDbMongo);
279291
app.useReadAndWriteThroughStrategy();
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String splitLine = "==============================================";
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LOGGER.info(splitLine);
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app.useReadThroughAndWriteAroundStrategy();
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LOGGER.info(splitLine);
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app.useReadThroughAndWriteBehindStrategy();
297+
LOGGER.info(splitLine);
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app.useCacheAsideStategy();
299+
LOGGER.info(splitLine);
283300
}
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285302
public void useReadAndWriteThroughStrategy() {
286303
LOGGER.info("# CachingPolicy.THROUGH");
287-
AppManager.initCachingPolicy(CachingPolicy.THROUGH);
304+
appManager.initCachingPolicy(CachingPolicy.THROUGH);
305+
288306
var userAccount1 = new UserAccount("001", "John", "He is a boy.");
289-
AppManager.save(userAccount1);
290-
LOGGER.info(AppManager.printCacheContent());
291-
AppManager.find("001");
292-
AppManager.find("001");
307+
308+
appManager.save(userAccount1);
309+
LOGGER.info(appManager.printCacheContent());
310+
appManager.find("001");
311+
appManager.find("001");
293312
}
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295314
public void useReadThroughAndWriteAroundStrategy() { /* ... */ }
@@ -300,16 +319,6 @@ public class App {
300319
}
301320
```
302321

303-
Finally, here is some of the console output from the program.
304-
305-
```
306-
12:32:53.845 [main] INFO com.iluwatar.caching.App - # CachingPolicy.THROUGH
307-
12:32:53.900 [main] INFO com.iluwatar.caching.App -
308-
--CACHE CONTENT--
309-
UserAccount(userId=001, userName=John, additionalInfo=He is a boy.)
310-
----
311-
```
312-
313322
## Class diagram
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315324
![alt text](./etc/caching.png "Caching")

‎caching/etc/caching.png

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‎caching/src/main/java/com/iluwatar/caching/App.java

Lines changed: 20 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -44,10 +44,19 @@
4444
* </p>
4545
*
4646
* <p>
47-
* To run the application with MongoDb:
48-
* 1. Launch mongoDB in docker container with command: docker-compose up
49-
* 2. Start application with parameter --mongo
50-
* Example: java -jar app.jar --mongo
47+
* There are 2 ways to launch the application.
48+
* - to use "in Memory" database.
49+
* - to use the MongoDb as a database
50+
*
51+
* To run the application with "in Memory" database, just launch it without parameters
52+
* Example: 'java -jar app.jar'
53+
*
54+
* To run the application with MongoDb you need to be installed the MongoDb
55+
* in your system, or to launch it in the docker container.
56+
* You may launch docker container from the root of current module with command:
57+
* 'docker-compose up'
58+
* Then you can start the application with parameter --mongo
59+
* Example: 'java -jar app.jar --mongo'
5160
* </p>
5261
*
5362
* @see CacheStore
@@ -86,7 +95,13 @@ public static void main(final String[] args) {
8695
// and the App class to avoid Maven compilation errors. Set flag to
8796
// true to run the tests with MongoDB (provided that MongoDB is
8897
// installed and socket connection is open).
89-
App app = new App(isDbMongo(args));
98+
boolean isDbMongo = isDbMongo(args);
99+
if (isDbMongo) {
100+
LOGGER.info("Using the Mongo database engine to run the application.");
101+
} else {
102+
LOGGER.info("Using the 'in Memory' database to run the application.");
103+
}
104+
App app = new App(isDbMongo);
90105
app.useReadAndWriteThroughStrategy();
91106
String splitLine = "==============================================";
92107
LOGGER.info(splitLine);

‎caching/src/main/java/com/iluwatar/caching/CacheStore.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -36,7 +36,7 @@
3636
@Slf4j
3737
public class CacheStore {
3838
/**
39-
* Cach capacity.
39+
* Cache capacity.
4040
*/
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private static final int CAPACITY = 3;
4242

‎caching/src/main/java/com/iluwatar/caching/LruCache.java

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -177,7 +177,7 @@ public void set(final String userId, final UserAccount userAccount) {
177177
}
178178

179179
/**
180-
* Che if Cache cintains the userId.
180+
* Check if Cache contains the userId.
181181
*
182182
* @param userId {@link String}
183183
* @return boolean

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