InMemoryCache #2
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| package com.lld.inmemorycache.model; | |||
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| public interface IEvictionPolicy { | |||
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Although the naming convention for interfaces starting with I is valid and mostly this convention is used in C++ or C#, in this repo, we have used the convention as following:
Interface - MyService
Class - MyServiceImpl under a impl package in the same directory as the interfaces.
Please follow the convention to make the repo consistent.
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| package com.lld.inmemorycache.model; | |||
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| public abstract class AbstractCache { | |||
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Instead of having both the key and value as String type, it would be better if the design supports key of type <K extends Comparable<K>> and value of type V.
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| 1. Cache should support get(), put methods. | ||
| 2. For simplicity, all keys and values are string. | ||
| 3. Make it extendable to support multiple other eviction policies in the future. |
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More could be added like support generic key value pairs, concurrency.
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| package com.lld.inmemorycache.model; | |||
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| public interface IStorage { | |||
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public interface Storage<K, V>
| lock.lock(); | ||
| try { | ||
| // access _storage. do not allow an exception here. | ||
| _storage.remove(key); |
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What exception is thrown here?
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| @Override | ||
| public void keyAccessed(String key) { | ||
| lock.lock(); |
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As mentioned, taking individual locks at the storage or eviction layer won't work.
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| public LRUEvictionPolicy() { | ||
| keys = new DoublyLinkedList(); | ||
| mapper = new LinkedHashMap<>(); |
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Looks like managing a hash map here just to find out if the eviction policy has a key or not is an overkill. Already storage layer is maintaining another hash map. If we maintain a map here, it just doubles the space with not much gain. Probably we can simply remove / get the key from the double linked list when a key is accessed or removed from the cache and return either the node or null to differentiate whether the operation was successful.
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| public class MainApplication { | ||
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| public static void main(String[] args) |
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Suggest writing multiple tests simulating multiple scenarios.
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@devanshu0987 would it be possible for you to address the comments? |
Design a Cache with LRU cache eviction policy.