Data cache

In-memory and persistent cache for Android

Gradle

repositories {
    maven{url "https://github.com/shaubert/maven-repo/raw/master/releases"}
}
dependencies {
    compile 'com.shaubert.cache:library:1.2.1'
}

Requirements

Android API >= 11

Basic How-to

Create Cache instance and configure it like this:

public static final int STORAGE_VERSION = 1;

public Cache setupCache(Context context) {
    //EntryKeyFactory converts Class and optional data qualifier to cache entry key 
    EntryKeyFactory keyFactory = new DefaultEntryKeyFactory();
    
    //you can setup persistable storage for your data classes annotated with @PersistableData
    DataStorage dataStorage = FileStorage.newBuilder(context)
            .version(STORAGE_VERSION)
            .debugMode(true) //if you want to read logs and get exceptions if serialization failed
            .dataSerializer() //your serializer, by default it is JavaSerializer
            .defaultDataCallback() //if you want to override data loading
            .build();
    
    //EntryFactory creates cache entries, please check Entry class.
    EntryFactory entryFactory = new DefaultEntryFactory(keyFactory, dataStorage);
    
    //finally create cache
    return new DefaultCache(keyFactory, entryFactory);
}

For example you have Response class:

public static class Response {
    String someData;
}

And you want to put Response into cache. You have to call:

Response response = ...;
Cache cache = ...;
Entry<Response> entry = cache.get(Response.class);
entry.setValue(response);

If you want to read your Response from cache:

Cache cache = ...;
Entry<Response> entry = cache.get(Response.class);
Response response = entry.getValue();

Persistance

If you want to make your response persistable add PersistableData annotation to Response class and pass not null DataStorage to DefaultEntryFactory constructor:

@PersistableData(Response.PersistableCallback.class)
public static class Response {
    String someData;

    public static class PersistableCallback implements PersistentEntryCallback<Response> {
        @Override
        public void onDataLoaded(Response response) {

        }

        @Override
        public void onDataLoadingError() {

        }

        @Override
        public void onEmptyDataLoaded() {

        }

        @Override
        public void onDataSaved(Response response) {

        }

        @Override
        public void onDataSavingError() {

        }
    }
}

Note that by default FileStorage uses JavaSerializer. You can easily implement for example GSONSerializer just look at DataSerializer interface:

public class GsonSerializer implements DataSerializer {
    private Gson gson;

    public GsonSerializer(Gson gson) {
        this.gson = gson;
    }

    @Override
    public boolean isApplicable(Class<?> aClass) {
        return true;
    }

    @Override
    public <T> void serialize(T t, OutputStream outputStream) throws IOException {
        JsonWriter jsonWriter = new JsonWriter(new OutputStreamWriter(outputStream));
        gson.toJson(t, t.getClass(), jsonWriter);
        jsonWriter.flush();
    }

    @Override
    public <T> T deserialize(Class<T> tClass, InputStream inputStream) throws IOException {
        JsonReader jsonReader = new JsonReader(new InputStreamReader(inputStream));
        return gson.fromJson(jsonReader, tClass);
    }
}

Note that on persistable data entry.getValue() will return null while data is loading. If you want you can pass callback to getValue like this:

((AsyncEntry<Response>) t).getValue(new DataCallback<Response>() {
    @Override
    public void onDataResult(Response response) {
        //response or null if error occurred or response wasn't in storage
    }
});

DefaultEntryFactory will create AsyncEntry for all classes with PersistableData annotation if DataStorage not null.

Marks

Also you can manage marks to your entry. For example when you want to mark your cache entry as loading while executing request. Marks available out of the box:

• Entry.DIRTY_MARK
• Entry.FAILURE_MARK
• Entry.UPDATING_MARK

Mergeable Data

Implement MergeableData interface in your data class to automatically perform merge onentry.setValue() if cache entry contains data.