JSON Support in NCache

NCache provides JSON support, a structured, human-readable, lightweight syntax for parsing, and data sharing. The major ease provided by NCache to you through Cache Data as JSON is the flexibility of retrieving data of any custom class in your cache as JSON. Moreover, data can be added as JSON and retrieved and parsed as a custom class.

NCache supports JSON through:

• NCache JSON API
• JSON Serialization in Cache

var product = FetchProductFromDB("1001");
string jsonString = @$"{{ 
			""ProductID"" : ""{product.ProductID}"",
			""ProductName"" : ""{product.ProductName}"",
			""Category"" : ""{product.Category}"",
			""UnitsAvailable"" : ""{product.UnitsAvailable}""
			}}";
JsonObject jsonObject = new JsonObject(jsonString, "Alachisoft.NCache.Sample.Product");
string key = "Product:" + product.ProductID;

// Inserting object in cache
cache.Insert(key, jsonObject);

Product product = Product.fetchProductFromDB("Product:1001");
String jsonString = "{\"ProductID\":\"" + product.getProductID() + "\"," +
		    "\"ProductName\":\"" + product.getProductName() + "\"," +
		    "\"Category\":\"" + product.getCategory() + "\"," +
		    "\"UnitsAvailable\":" + product.getUnitsAvailable() +
		    "}";
JsonObject jsonObject = new JsonObject(jsonString, "com.alachisoft.ncache.sample.Product");
String key = "Product:" + product.getProductID();

// Inserting object in Cache
cache.insert(key, jsonObject);

var jsonObject = cache.Get<JsonObject>(key);

var jsonObject = cache.get(key, JsonObject.class);

JSON Array

JsonArray in NCache is the representation of JArray in JSON standards. JsonArray is an ordered list of values. These values can be string, number, boolean, object, or another array.

Add JsonArray in Cache

You can add JsonObject or even another JsonArray in a JsonArray. NCache uses the indexer property to add and update values in a JsonArray. You can create a JsonArray using a JsonObject in the following way:

• .NET
• Java

var jsonArray = new JsonArray();
...                 
var jsonObject1 = new JsonObject(jsonString1 );
jsonArray.Add(jsonObject1);

var jsonObject2 = new JsonObject(jsonString2);
jsonArray.Add(jsonObject2);

string key = “JsonArrray:1001”;
cache.Insert(key, jsonArray);

var jsonArray = new JsonArray();
        //...
var jsonObject1 = new JsonObject(jsonString1, "com.alachisoft.ncache.sample.Product");
jsonArray.add(jsonObject1);
var jsonObject2 = new JsonObject(jsonString2, "com.alachisoft.ncache.sample.Product");
jsonArray.add(jsonObject2);

String key = "JsonArray:1001";

// Inserting JsonArray in Cache
cache.insert(key, jsonArray);

In NCache, you can also add JSON data at specified indices in a JsonArray. If an item already exists at the specified index, it is overwritten. If the specified index does not exist, the item is added at that index and all the values between the last populated index and the new index are set to JsonNull (null in JSON standards).

Retrieve JsonArray or its Particular Index Value

NCache allows you to fetch the entire JsonArray from the cache or retrieve the value from a particular index on the JsonArray. Once retrieved, you can enumerate it or perform index-based operations on the data. This is how you can fetch a JsonArray or a particular value from the cache:

• .NET
• Java

// Retrieve JsonArray from cache
string key = "JsonArray:1001";
JsonArray jsonArray = cache.Get<JsonArray>(key)

// Retrieve the value of the specified index
JsonValueBase value = jsonArray[2];

// Retrieve JSONArray from cache
String key = "JsonArray:1001";
JsonArray jsonArray = cache.get(key, JsonArray.class);

// Retrieve the value of the specified index
JsonValueBase value = jsonArray.getItem(2);

• NCache Details
• JSON Data in Cache
• NCache as JSON Store

JSON Enumerator

NCache also allows you to take JsonEnumerator on cache to fetch all JSON Objects and JSON Arrays in the following way:

• .NET
• Java

var enumerator = (IDictionaryEnumerator)_cache.GetJsonEnumerator();
while (enumerator.MoveNext())
{
	DictionaryEntry entry = (DictionaryEntry)enumerator.Current;
	JsonValueBase valueBase = (JsonValueBase)entry.Value;
	//...
}

var enumerator = cache.asJsonIterator();
while (enumerator.hasNext())
{
	Entry entry = (Entry) enumerator.next();
	JsonValueBase valueBase =  (JsonValueBase) entry.getValue();
	//...
 }

NCache Features Supported with JSON

NCache is a feature-rich distributed cache that provides many features to ease you into storing and retrieving your data. Just like for native and custom objects, NCache also supports such features for JSON-type data.

Index JSON Data in Cache

NCache allows you to index JSON data based on its type.

• .NET
• Java

Product product = FetchProductFromDB();
string jsonString = @$"{{ ""ProductID"" : ""{product.ProductID}"", ""ProductName"" : ""{product.ProductName}"", ""Price"" : {product.Price} }}";

JsonObject jsonObject = new JsonObject(jsonString, "Alachisoft.NCache.Sample.Product");
string key = "Product:" + product.ProductID;

cache.Insert(key, jsonObject);

Product product = Product.fetchProductFromDB("Product:1001");

String jsonString = "{\"productID\":\"" + product.getProductID() + "\", \"productName\" : \""+ product.getProductName() + "\", \"price\":\"" + product.getPrice() + "\"}";

JsonObject jsonObject = new JsonObject(jsonString,"com.alachisoft.ncache.sample.Product" );
String key = "Product:" +product.getProductID();
cache.insert(key, jsonObject);

Query JSON Data in Cache

Once you have indexed JSON data based on its type, you can perform SQL-like queries to fetch or delete the data from the cache. For more information on how to use all these searchable attributes while querying JSON data, refer to our documentation on Query JSON Data.

• .NET
• Java

string query = "Select * FROM Alachisoft.NCache.Runtime.JSON.JsonObject WHERE Discount = ?";
QueryCommand queryCommand = new QueryCommand(query);queryCommand.Parameters.Add("Discount", 0.5);

var queryResult = cache.SearchService.ExecuteReader(queryCommand);

 // QueryResult contains all the keys and metadata of result
 if (queryResult.FieldCount > 0) {
            while (queryResult.Read()) {
                // Perform operation according to your logic
            }
        }
else
{
	// No data
}

String query = "Select * FROM Alachisoft.NCache.Runtime.JSON.JsonObject WHERE Discount = ?";
QueryCommand queryCommand = new QueryCommand(query);
queryCommand.getParameters().put("Discount", 0.5);

var queryResult = cache.getSearchService().executeReader(queryCommand);
if (queryResult.getFieldCount() > 0) {
      while (queryResult.read()) {
      // Perform operation according to your logic
      }
}
else {
            // No data
        }

Sync JSON Data with Database

When storing data in the cache, NCache allows you to ensure that the data you are working with is not stale. To ensure this, NCache has provided the following features that keep your cache and database synchronized.

• Cache Dependencies: NCache supports cache dependencies on the JSON data that removes data from the cache if it is updated in the database. Learn more about Cache Data Dependency on Database from our documentation.
• Expiration: You can add time-based expiration on your JSON data so that your cache is synchronized with the database. For more details, refer to our documentation on Data Expiration Strategies in Cache.
• Events: NCache provides event notifications that are triggered when any registered operation is performed on your JSON serialized cache or JSON data. For more details, refer to our documentation on Event Notifications in Cache.
• Data Source Providers: NCache allows persisting JSON data to the master data source and fetches data directly from the source if it is not found in the cache. Refer to our documentation on Data Source Providers for Cache to get detailed help on these providers.
• Cache Startup Loader: JSON data can be automatically added to the cache when the cache starts using the Cache Startup Loader. For more details, refer to our documentation on Cache Startup Loader.

Product product = new Product();
product.Name = "Pizza";
product.Expiry = new DateTime(2020, 3, 28);
product.Sizes = new string[] { "Large", "Medium" };

Product product = new Product();
product.setName("Pizza");
product.setExpiry(new Date(2020, 3, 28));
product.setSizes(new String[] { "Large", "Medium" });

{
   "Name": "Pizza",
   "Expiry": "2020-3-28T00:00:00",
   "Sizes": ["Large", "Medium"]
}

What to Do Next?