Caching pattern: Documentation and diagram

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

@@ -26,22 +26,23 @@ package com.iluwatar.caching;
  *
  * The Caching pattern describes how to avoid expensive re-acquisition of resources by not releasing
  * the resources immediately after their use. The resources retain their identity, are kept in some
- * fast-access storage, and are re-used to avoid having to acquire them again. There are three main
- * caching strategies/techniques in this pattern; each with their own pros and cons. They are:
+ * fast-access storage, and are re-used to avoid having to acquire them again. There are four main
+ * caching strategies/techniques in this pattern; each with their own pros and cons. They are;
  * <code>write-through</code> which writes data to the cache and DB in a single transaction,
- * <code>write-around</code> which writes data immediately into the DB instead of the cache, and
+ * <code>write-around</code> which writes data immediately into the DB instead of the cache,
  * <code>write-behind</code> which writes data into the cache initially whilst the data is only
- * written into the DB when the cache is full. The <code>read-through</code> strategy is also
- * included in the mentioned three strategies -- returns data from the cache to the caller <b>if</b>
- * it exists <b>else</b> queries from DB and stores it into the cache for future use. These
- * strategies determine when the data in the cache should be written back to the backing store (i.e.
- * Database) and help keep both data sources synchronized/up-to-date. This pattern can improve
- * performance and also helps to maintain consistency between data held in the cache and the data in
- * the underlying data store.
+ * written into the DB when the cache is full, and <code>cache-aside</code> which pushes the
+ * responsibility of keeping the data synchronized in both data sources to the application itself.
+ * The <code>read-through</code> strategy is also included in the mentioned four strategies --
+ * returns data from the cache to the caller <b>if</b> it exists <b>else</b> queries from DB and
+ * stores it into the cache for future use. These strategies determine when the data in the cache
+ * should be written back to the backing store (i.e. Database) and help keep both data sources
+ * synchronized/up-to-date. This pattern can improve performance and also helps to maintain
+ * consistency between data held in the cache and the data in the underlying data store.
  * <p>
  * In this example, the user account ({@link UserAccount}) entity is used as the underlying
  * application data. The cache itself is implemented as an internal (Java) data structure. It adopts
- * a Least-Recently-Used (LRU) strategy for evicting data from itself when its full. The three
+ * a Least-Recently-Used (LRU) strategy for evicting data from itself when its full. The four
  * strategies are individually tested. The testing of the cache is restricted towards saving and
  * querying of user accounts from the underlying data store ( {@link DbManager}). The main class (
  * {@link App} is not aware of the underlying mechanics of the application (i.e. save and query) and

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

@@ -24,7 +24,7 @@ package com.iluwatar.caching;
 
 /**
  *
- * Enum class containing the three caching strategies implemented in the pattern.
+ * Enum class containing the four caching strategies implemented in the pattern.
  *
  */
 public enum CachingPolicy {

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

@@ -73,7 +73,6 @@ public class LruCache {
   }
 
   /**
-   *
    * Remove node from linked list.
    */
   public void remove(Node node) {
@@ -90,7 +89,6 @@ public class LruCache {
   }
 
   /**
-   *
    * Move node to the front of the list.
    */
   public void setHead(Node node) {
@@ -161,7 +159,6 @@ public class LruCache {
   }
 
   /**
-   *
    * Returns cache data in list form.
    */
   public List<UserAccount> getCacheDataInListForm() {

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

@@ -23,9 +23,7 @@
 package com.iluwatar.caching;
 
 /**
- *
  * Entity class (stored in cache and DB) used in the application.
- *
  */
 public class UserAccount {
   private String userId;