How to implement cache (LRU Cache) using LinkedHashMap in java

Recently i wanted to implement a simple Least recently used (LRU) cache in one my applications. But my use case is simple enough that instead of going for something ehcache i decided to build it on own by using java.util.LinkedHashMap
As you can see from the code its very simple. All you have to do is extend java.util.LinkedHashMap and override its protected removeEldestEntry() method so that it checks if the size of map is greater than a size you specified while creating the Map if yes remove the eldest entry
Now the question is when Map is full which entry will it remove, you have 2 options
  1. Eldest: If you just want to remove the first entry that you inserted in the Map when adding a new entry then in your constructor you could use super(cacheSize, 0.75f);, so LinkedHashMap wont keep track of when a particular entry were accessed.
  2. Least recently used (LRU): But if you want to make sure that the entry that was least recently used should be removed then call super(cacheSize, 0.75f, true); from constructor of your LRUCache so that LinkedHashMap keeps track of when entry was accessed and removes the Least recently used entry

2 comments:

Anonymous said...

Here is the pic of the setup I have<

you can look at the image over here https://www.dropbox.com/s/ubik71rxfz2rg25/issue-class-not-found.JPG?dl=0

Jason Borne said...

We are a third party technical support service. Avast Customer Support is here to help you out with the whole procedure to Download Avast Antivirus online, We not only fix your Avast Support related issues but will guide with how to get started with your new Avast product once it gets installed successfully. Call on our Toll Free no. 1 855 966 3855
Gmail Customer service is a third party technical support service for Gmail users when they face any technical issue or error in their Gmail account. Our Gmail Customer Support team solves issues like forgot Gmail account password, Gmail configuration or Sync issues, recover deleted emails and many more. Toll Free number (800) 986-9271
How you install or reinstall Office 365 or Office 2016 depends on whether your Office product is part of an Office for home or Office for business plan. If you're not sure what you have, see what office com setup products are included in each plan and then follow the steps for your product. The steps below also apply if you're installing a single, stand-alone Office application such as Access 2016 or Visio 2016. Need Help with office setup Enter Product Key? Call 1-800-000-0000 Toll Free
Norton Tech Support is a third party service provider and not in any way associated with Norton or any of its partner companies. We offer support for Norton products and sell subscription based additional warranty on computer and other peripheral devices. Call our Toll Free number 1 855 966 3855
Other Services
Norton Toll Free , Office-Setup , office.com/setup.