JSONStore in Android applications

Download Android Studio project Download Adapter Maven project

Prerequisites

Read the JSONStore parent tutorial
Make sure the PMF Native SDK was added to the Android Studio project. Follow the Adding the PMF SDK to Android applications tutorial.

Adding JSONStore

In Android → Gradle Scripts, select the build.gradle (Module: app) file.
Place the pmfjsonstore aar files to the app\libs folder. Add the following to the existing dependencies section:

implementation fileTree(include: ['*.aar'], dir: 'libs')
implementation 'com.fasterxml.jackson.core:jackson-core:2.14.1'
implementation 'com.fasterxml.jackson.core:jackson-databind:2.14.1'
implementation 'com.fasterxml.jackson.core:jackson-annotations:2.14.1'

Add the following to the “DefaultConfig” section of your build.gradle file.

  ndk {
        abiFilters "armeabi", "armeabi-v7a", "x86", "mips"
      }

Note : We add the abiFilters to ensure that the apps having JSONStore will run in any of the architectures specified above. This is required as JSONStore is dependent on a third party library which supports only these architectures .

Basic Usage

Open

Use openCollections to open one or more JSONStore collections.

Starting or provisioning a collections means creating the persistent storage that contains the collection and documents, if it does not exists. If the persistent storage is encrypted and a correct password is passed, the necessary security procedures to make the data accessible are run.

For optional features that you can enable at initialization time, see Security, Multiple User Support and PMF Adapter Integration in the second part of this tutorial.

Context context = getContext();
try {
  JSONStoreCollection people = new JSONStoreCollection("people");
  people.setSearchField("name", SearchFieldType.STRING);
  people.setSearchField("age", SearchFieldType.INTEGER);
  List<JSONStoreCollection> collections = new LinkedList<JSONStoreCollection>();
  collections.add(people);
  WLJSONStore.getInstance(context).openCollections(collections);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Get

Use getCollectionByName to create an accessor to the collection. You must call openCollections before you call getCollectionByName.

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

The variable collection can now be used to perform operations on the people collection such as add, find, and replace

Add

Use addData to store data as documents inside a collection

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  //Add options.
  JSONStoreAddOptions options = new JSONStoreAddOptions();
  options.setMarkDirty(true);
  JSONObject data = new JSONObject("{age: 23, name: 'yoel'}")
  collection.addData(data, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Find

Use findDocuments to locate a document inside a collection by using a query. Use findAllDocuments to retrieve all the documents inside a collection. Use findDocumentById to search by the document unique identifier.

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreQueryPart queryPart = new JSONStoreQueryPart();
  // fuzzy search LIKE
  queryPart.addLike("name", name);
  JSONStoreQueryParts query = new JSONStoreQueryParts();
  query.addQueryPart(queryPart);
  JSONStoreFindOptions options = new JSONStoreFindOptions();
  // returns a maximum of 10 documents, default: returns every document
  options.setLimit(10);
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  List<JSONObject> results = collection.findDocuments(query, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Replace

Use replaceDocument to modify documents inside a collection. The field that you use to perform the replacement is _id, the document unique identifier.

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  JSONStoreReplaceOptions options = new JSONStoreReplaceOptions();
  // mark data as dirty
  options.setMarkDirty(true);
  JSONStore replacement = new JSONObject("{_id: 1, json: {age: 23, name: 'chevy'}}");
  collection.replaceDocument(replacement, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

This examples assumes that the document {_id: 1, json: {name: 'yoel', age: 23} } is in the collection.

Remove

Use removeDocumentById to delete a document from a collection. Documents are not erased from the collection until you call markDocumentClean. For more information, see the PMF Adapter Integration section later in this tutorial.

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  JSONStoreRemoveOptions options = new JSONStoreRemoveOptions();
  // Mark data as dirty
  options.setMarkDirty(true);
  collection.removeDocumentById(1, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Remove Collection

Use removeCollection to delete all the documents that are stored inside a collection. This operation is similar to dropping a table in database terms.

Context context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  collection.removeCollection();
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Destroy

Use destroy to remove the following data:

All documents
All collections
All Stores - See Multiple User Support later in this tutorial
All JSONStore metadata and security artifacts - See Security later in this tutorial

Context context = getContext();
try {
  WLJSONStore.getInstance(context).destroy();
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Advanced Usage

Security

You can secure all the collections in a store by passing a JSONStoreInitOptions object with a password to the openCollections function. If no password is passed, the documents of all the collections in the store are not encrypted.

Some security metadata is stored in the shared preferences (Android).
The store is encrypted with a 256-bit Advanced Encryption Standard (AES) key. All keys are strengthened with Password-Based Key Derivation Function 2 (PBKDF2).

Use closeAll to lock access to all the collections until you call openCollections again. If you think of openCollections as a login function you can think of closeAll as the corresponding logout function.

Use changePassword to change the password.

Context context = getContext();
try {
  JSONStoreCollection people = new JSONStoreCollection("people");
  people.setSearchField("name", SearchFieldType.STRING);
  people.setSearchField("age", SearchFieldType.INTEGER);
  List<JSONStoreCollection> collections = new LinkedList<JSONStoreCollection>();
  collections.add(people);
  JSONStoreInitOptions options = new JSONStoreInitOptions();
  options.setPassword("123");
  WLJSONStore.getInstance(context).openCollections(collections, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

Multiple User Support

You can create multiple stores that contain different collections in a single PMF application. The openCollections function can take an options object with a username. If no username is given, the default username is ““jsonstore””.

Context context = getContext();
try {
  JSONStoreCollection people = new JSONStoreCollection("people");
  people.setSearchField("name", SearchFieldType.STRING);
  people.setSearchField("age", SearchFieldType.INTEGER);
  List<JSONStoreCollection> collections = new LinkedList<JSONStoreCollection>();
  collections.add(people);
  JSONStoreInitOptions options = new JSONStoreInitOptions();
  options.setUsername("yoel");
  WLJSONStore.getInstance(context).openCollections(collections, options);
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

PMF Adapter Integration

This section assumes that you are familiar with adapters. Adapter Integration is optional and provides ways to send data from a collection to an adapter and get data from an adapter into a collection. You can achieve these goals by using functions such as WLResourceRequest or your own instance of an HttpClient if you need more flexibility.

Adapter Implementation

Create an adapter and name it “JSONStoreAdapter”. Define it’s procedures addPerson, getPeople, pushPeople, removePerson, and replacePerson.

function getPeople() {
	var data = { peopleList : [{name: 'chevy', age: 23}, {name: 'yoel', age: 23}] };
	WL.Logger.debug('Adapter: people, procedure: getPeople called.');
	WL.Logger.debug('Sending data: ' + JSON.stringify(data));
	return data;
}
function pushPeople(data) {
	WL.Logger.debug('Adapter: people, procedure: pushPeople called.');
	WL.Logger.debug('Got data from JSONStore to ADD: ' + data);
	return;
}
function addPerson(data) {
	WL.Logger.debug('Adapter: people, procedure: addPerson called.');
	WL.Logger.debug('Got data from JSONStore to ADD: ' + data);
	return;
}
function removePerson(data) {
	WL.Logger.debug('Adapter: people, procedure: removePerson called.');
	WL.Logger.debug('Got data from JSONStore to REMOVE: ' + data);
	return;
}
function replacePerson(data) {
	WL.Logger.debug('Adapter: people, procedure: replacePerson called.');
	WL.Logger.debug('Got data from JSONStore to REPLACE: ' + data);
	return;
}

Load data from PMF Adapter

To load data from an adapter use WLResourceRequest.

WLResponseListener responseListener = new WLResponseListener() {
  @Override
  public void onFailure(final WLFailResponse response) {
    // handle failure
  }
  @Override
  public void onSuccess(WLResponse response) {
    try {
      JSONArray loadedDocuments = response.getResponseJSON().getJSONArray("peopleList");
    } catch(Exception e) {
      // error decoding JSON data
    }
  }
};

try {
  WLResourceRequest request = new WLResourceRequest(new URI("/adapters/JSONStoreAdapter/getPeople"), WLResourceRequest.GET);
  request.send(responseListener);
} catch (URISyntaxException e) {
  // handle error
}

Get Push Required (Dirty Documents)

Calling findAllDirtyDocuments returns and array of so called “dirty documents”, which are documents that have local modifications that do not exist on the back-end system.

Context  context = getContext();
try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  List<JSONObject> dirtyDocs = collection.findAllDirtyDocuments();
  // handle success
} catch(JSONStoreException e) {
  // handle failure
}

To prevent JSONStore from marking the documents as “dirty”, pass the option options.setMarkDirty(false) to add, replace, and remove.

Push changes

To push changes to an adapter, call the findAllDirtyDocuments to get a list of documents with modifications and then use WLResourceRequest. After the data is sent and a successful response is received make sure you call markDocumentsClean.

WLResponseListener responseListener = new WLResponseListener() {
  @Override
  public void onFailure(final WLFailResponse response) {
    // handle failure
  }
  @Override
  public void onSuccess(WLResponse response) {
    // handle success
  }
};
Context context = getContext();

try {
  String collectionName = "people";
  JSONStoreCollection collection = WLJSONStore.getInstance(context).getCollectionByName(collectionName);
  List<JSONObject> dirtyDocuments = people.findAllDirtyDocuments();

  JSONObject payload = new JSONObject();
  payload.put("people", dirtyDocuments);

  WLResourceRequest request = new WLResourceRequest(new URI("/adapters/JSONStoreAdapter/pushPeople"), WLResourceRequest.POST);
  request.send(payload, responseListener);
} catch(JSONStoreException e) {
  // handle failure
} catch (URISyntaxException e) {
  // handle error
}

Image of the sample application

Sample application

The JSONStoreAndroid project contains a native Android application that utilizes the JSONStore API set.
Included is a JavaScript adapter Maven project.

Click to download the Native Android project.
Click to download the adapter Maven project.

Sample usage

Follow the sample’s README.md file for instructions.

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