IdentifiableJsonMySqlPersistence<T extends IIdentifiable<K>, K>

Extends: IdentifiableMySqlPersistence<T, K>

Description

The IdentifiableJsonMySqlPersistence class allows you to create persistence components that store data in JSON or JSONB fields and implement a number of CRUD operations over data items with unique ids.

Important points

• The JSON table has only two fields: id and data.
• In basic scenarios child classes shall only override getPageByFilter, getListByFilter or deleteByFilter operations with a specific filter function.
• All other operations can be used out of the box.
• In complex scenarios child classes can implement additional operations by accessing this._collection and this._model properties.

Configuration parameters

• table: (optional) MySQL table name
• schema: (optional) MySQL schema name

connection(s):

• discovery_key: (optional) key to retrieve the connection from IDiscovery
• host: host name or IP address
• port: port number (default: 27017)
• uri: resource URI or connection string with all parameters in it

credential(s):

• store_key: (optional) key to retrieve the credentials from ICredentialStore
• username: (optional) username
• password: (optional) user’s password

options:

• connect_timeout: (optional) number of milliseconds to wait before timing out when connecting a new client (default: 0)
• idle_timeout: (optional) number of milliseconds a client must sit idle in the pool and not be checked out (default: 10000)
• max_pool_size: (optional) maximum number of clients the pool can contain (default: 10)

References

• *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
• *:discovery:*:*:1.0 - (optional) IDiscovery services
• *:credential-store:*:*:1.0 - (optional) ICredentialStore to resolve credentials

Constructors

Creates a new instance of the persistence component.

public IdentifiableJsonMySqlPersistence(Class documentClass, String tableName, String schemaName)

• tableName: String - (optional) collection name.
• schemaName: String - (optional) a schema name.

Instance methods

convertFromPublic

Converts object value from public to internal format.

protected Map<String, Object> convertFromPublic(Object value)

• value: Object - object in public format to convert.
• returns: Map<String, Object> - converted object in internal format.

convertToPublic

Converts object value from internal to public format.

protected T convertToPublic(Map<String, Object> value)

• value: Map<String, Object> - object in internal format to convert.
• returns: T - converted object in public format.

ensureTable

Adds DML statement to automatically create a JSON(B) table

protected void ensureTable(String idType, String dataType)

• idType: String - type of the id column (default: VARCHAR(32))
• dataType: String - type of the data column (default: JSON)

updatePartially

Updates only few selected fields in a data item.

public T updatePartially(IContext context, K id, AnyValueMap data)

• context: IContext - (optional) a context to trace execution through a call chain.
• id: K - id of the data item to be updated.
• data: AnyValueMap - map with fields to be updated.
• return: - updated item

Examples

{@code
 public class MyJsonMySqlPersistence extends IdentifiableMySqlJsonPersistence<MyData, String> {

     public MyJsonMySqlPersistence() {
         super(MyData.class, "dummies", null);
     }

     @Override
     protected void defineSchema() {
         this.clearSchema();
         this.ensureTable();
         this.ensureSchema("ALTER TABLE `" + this._tableName + "` ADD `data_key` VARCHAR(50) AS (JSON_UNQUOTE(`data`->\"$.key\"))");
         this.ensureIndex(this._tableName + "_json_key", Map.of("data_key", 1), Map.of("unique", true));
     }

     public DataPage<MyData> getPageByFilter(IContext context, FilterParams filter, PagingParams paging) {
         filter = filter != null ? filter : new FilterParams();
         var key = filter.getAsNullableString("key");

         String filterCondition = null;
         if (key != null)
             filterCondition = "data->'$.key'='" + key + "'";

         return super.getPageByFilter(context, filterCondition, paging, null, null);
     }
 }
 ...
 var persistence = new MyJsonMySqlPersistence(MyData.class);
 persistence.configure(ConfigParams.fromTuples(
         "host", "localhost",
         "port", 3306
 ));

 persistence.open(null);

 persistence.create("123", new MyData("1", "ABC", "content"));
 var page = persistence.getPageByFilter("123", FilterParams.fromTuples("key", "ABC"), null);

 var deletedItem = persistence.deleteById("123", "1");
 }