RepositoryCache

Annotation Processor that aims to help developers to get an easy strategy for their repositories.

This is a Java library that can be imported both in Android or Java projects.

Features:

• Fast implementation for each repository method.
• Provides simple methods like isCached or isExpired.
• Distinguish between different calls of the same method.
• Provides the ability to store content on disk without the need of a database.

Dependency

Latest stable version:

In order to generate the proxy classes when building your project, you need to apply the android-apt gradle plugin to run annotation processing.

If you are working with gradle, add the dependency to your build.gradle file:

dependencies{

  compile 'com.kuassivi.annotation:repository-cache:?.?.?'
  apt 'com.kuassivi.compiler:repository-cache-compiler:?.?.?' 
}

If you are working with maven, do it into your pom.xml

<dependency>
  <groupId>com.kuassivi.annotation</groupId>
  <artifactId>repository-cache</artifactId>
  <version>?.?.?</version>
  <type>pom</type> </dependency> <dependency>
  <groupId>com.kuassivi.compiler</groupId>
  <artifactId>repository-cache-compiler</artifactId>
  <version>?.?.?</version>
  <type>pom</type> </dependency>

How to:

Suppose you often define some contracts for your repositories. If so then you can annotate each of your methods with the RepositoryCache annotation and provide a time to expire.

Regular classes, not just interfaces, can be annotated as well.

Lets see an example:

public interface MyRepository {

@RepositoryCache(DateUtils.MINUTE_IN_MILLIS * 60) // expiration time in ms.
  Object getDataById(int id);

}

Now build your project!

Once you have built the project, a new Java Proxy Class will be created in your build source apt folder.

The Proxy Class generated will looks like: RepositoryClassName + ProxyCache suffix.

For instance, MyRepositoryProxyCache.

Lets see how to use the Proxy Class:

public class MyRepositoryImpl implements MyRepository {

@Override
  public Object getDataById(int id) {

  // Gets an instance of the cached method

RepositoryProxyCache cache = MyRepositoryProxyCache.getDataById(context.getCacheDir());

// Ensure we are getting distinct cache instance per id.

cache.select( id );
 // Optional

// Checks whether it is cached and not expired.

if (!cache.isExpired()) {

 // [...] proceed retrieving data from your local store (maybe a database)

 
}
 else {

 // [...] otherwise proceed retrieving data from your cloud store (maybe a rest service)

  // Once you persist, it will store this method name with the specified id in the cache.

 if(!cache.isCached()) {

  cache.persist();

 
}

 
}

  
}

}

Tips:

- Use always an Interface as a contract. It is much clean.

- You can cache a method indefinitely, simply do not put any time on the annotation.

- Remember you can distinguish between calls with an ID or any other logic through the select() method.

- You can i.e. store your content inside the cache with persist(String) if you are not planning to have a database. Just transform your Object from/to a Json string and retrieve that content later with getContent().

ProxyCache methods:

• `select(Object)` - distinguish between different calls of the same method, the parameter should be any kind of an id of your choice. 

• `isCached()` - returns true if a method call is cached, false otherwise. 

• `isExpired()` - returns true if a method call is not cached or is expired, false otherwise. 

• `persist()` - stores a method call in the cache. 

• `persist(String)` - stores a method call in the cache with the provided content. 

• `getContent()` - retrieves the stored content of a specific method call. 

• `evict()` - removes a specific method call from the cache. 

RepositoryCacheManager utilities:

• `static hashMD5(String)` - generates a MD5 hash string of the provided String parameter. 

• `static hashCode(Object...)` - generates a hash code from the provided parameter objects. 

• `static evictAll(File)` - removes all cache repositories. You must provide the cache directory. 

License

Copyright 2016 Francisco Gonzalez-Armijo Riádigos

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.