ExpirableDiskLruCache

ExpirableDiskLruCache is a wrapper for DiskLruCache that allows expiring of key/value pairs by specifying evictionTimeSpan. It has very simple API. If required it allows you to encrypt cached data by simply enabling encryptionEnabled to true. By default, it uses Conceal by facebook for encryption. You can provide your custom encryption/decryption as well.

Eviction Logic

• During get it will check if currentTime > currentTime + evictionSpan. Cache entry is removed.
• When cache reaches the allocated size, oldest entry is removed from the cache(LRU). Eviction time is not considered at all.

Usage

Initialize

ExpirableDiskLruCache uses the internal storage allocated to your app. Before you can do anything, you need to initialize ExpirableDiskLruCache with the cache size.

try {
    ExpirableDiskLruCache.getInstance().init(this, 4096); //in bytes
} catch (Exception e) {
        //failure
}

or enable encryption

try {
    ExpirableDiskLruCache.getInstance().init(this, 4096, false, true); //in bytes
} catch (Exception e) {
        //failure
}

Third parameter is for enable logging. And fourth parameter is for enabling encryption. If you may want to use your custom encryption/decryption, use:

try {
    ExpirableDiskLruCache.getInstance().init(this, 4096, false, true, customEncrypterDecrypter); //in bytes
} catch (Exception e) {
        //failure
}

To create custom encrypter/decrypter simply implement EncrypterDecrypter.java

The best place to do this would be in your application's onCreate() method. Since this library depends directly on DiskLruCache, you can refer that project for more info on the maximum size you can allocate etc.

Put stuff

You can put objects into ExpirableDiskLruCache synchronously:

try {
    ExpirableDiskLruCache.getInstance().put("myKey",myObject, myEvictionTimeSpan);
} catch (Exception e) {
    //failure;
}

Or asynchronously:

    ExpirableDiskLruCache.getInstance().put("myKey",myObject, myEvictionTimeSpan, putCallback);

Get Stuff

You can get stuff out of ExpirableDiskLruCache synchronously.

try {
    ExpirableDiskLruCache.getInstance().get("myKey",MyClass.class);
} catch (Exception e) {
        //failure
}

Or asynchronously:

    ExpirableDiskLruCache.getInstance().get("myKey",MyClass.class, getCallback);

Check for existence

If you wish to know whether an object exists for the given key, you can use:

try {
    boolean objectExists = ExpirableDiskLruCache.getInstance().contains("myKey");
} catch (Exception e) {}

Remove Stuff

You can remove stuff out of ExpirableDiskLruCache synchronously:

try {
    ExpirableDiskLruCache.getInstance().remove("myKey");
} catch (Exception e) {
        //failure
}

or asynchronously:

    ExpirableDiskLruCache.getInstance().remove("myKey", deleteCallback);

Remove All

try {
    ExpirableDiskLruCache.getInstance().removeAll("myKey");
} catch (Exception e) {
        //failure
}

Including in your project

gradle:

Step 1. Add the JitPack repository to your build file

repositories {
    maven {
        url "https://jitpack.io"
    }
}

Step 2. Add the dependency in the form

dependencies {
    compile 'com.github.vijayrawatsan:ExpirableDiskLruCache:0.2'
}

maven:

Step 1. Add the JitPack repository to your build file

<repository>
    <id>jitpack.io</id>
    <url>https://jitpack.io</url>
</repository>

Step 2. Add the dependency in the form

<dependency>
    <groupId>com.github.vijayrawatsan</groupId>
    <artifactId>ExpirableDiskLruCache</artifactId>
    <version>0.2</version>
</dependency>

FAQs

What kind of objects can I add to ExpirableDiskLruCache?

Anything that GSON can serialize.

What happens if my cache size is exceeded?

Older objects will be removed in a LRU (Least Recently Used) order.

Contributing

Contributions welcome via Github pull requests. Please write test cases as well.

Credits

ExpirableDiskLruCache is just a tiny little convenience wrapper around the following fantastic projects:

• DiskLruCache
• SimpeDiskCache
• GSON
• Conceal

Thanks!

License

This project is licensed under the MIT License. Please refer the License.txt file.