Module org.apache.derby.tools
Package org.apache.derby.jdbc

Class EmbeddedDataSource

java.lang.Object
org.apache.derby.jdbc.BasicEmbeddedDataSource40
org.apache.derby.jdbc.ReferenceableDataSource
org.apache.derby.jdbc.EmbeddedDataSource
All Implemented Interfaces:
Serializable, Wrapper, Referenceable, ObjectFactory, CommonDataSource, DataSource, org.apache.derby.iapi.jdbc.EmbeddedDataSourceInterface
Direct Known Subclasses:
EmbeddedConnectionPoolDataSource, EmbeddedXADataSource
public class EmbeddedDataSource extends org.apache.derby.jdbc.ReferenceableDataSource implements Referenceable

This data source is suitable for an application using embedded Derby, running on full Java SE 6 and higher, corresponding to 4.0 and higher.

A DataSource is a factory for Connection objects. An object that implements the DataSource interface will typically be registered with a JNDI service provider.

EmbeddedDataSource automatically supports the correct JDBC specification version for the Java Virtual Machine's environment.

  • JDBC 4.0 - Java SE 6
  • JDBC 4.1 - Java SE 7
  • JDBC 4.2 - full Java SE 8

Use BasicEmbeddedDataSource40 if your application runs on Java 8 Compact Profile 2.

The following is a list of properties that can be set on a Derby DataSource object:

Standard DataSource properties (from JDBC 3.0 specification).

  • databaseName (String): Mandatory
    This property must be set and it identifies which database to access. If a database named wombat located at g:/db/wombat is to be accessed, then one should call setDatabaseName("g:/db/wombat") on the data source object.
  • dataSourceName (String): Optional
    Name for DataSource. Not used by the data source object. Used for informational purpose only.
  • description (String): Optional
    Description of the data source. Not used by the data source object. Used for informational purpose only.
  • password (String): Optional
    Database password for the no argument DataSource.getConnection(), ConnectionPoolDataSource.getPooledConnection() and XADataSource.getXAConnection() methods.
  • user (String): Optional
    Database user for the no argument DataSource.getConnection(), ConnectionPoolDataSource.getPooledConnection() and XADataSource.getXAConnection() methods.

Derby specific DataSource properties.
  • attributesAsPassword (Boolean): Optional
    If true, treat the password value in a DataSource.getConnection(String user, String password), ConnectionPoolDataSource.getPooledConnection(String user, String password) or XADataSource.getXAConnection(String user, String password) as a set of connection attributes. The format of the attributes is the same as the format of the attributes in the property connectionAttributes. If false the password value is treated normally as the password for the given user. Setting this property to true allows a connection request from an application to provide more authentication information that just a password, for example the request can include the user's password and an encrypted database's boot password.
  • connectionAttributes (String): Optional
    Defines a set of Derby connection attributes for use in all connection requests. The format of the String matches the format of the connection attributes in a Derby JDBC URL. That is a list of attributes in the form attribute=value, each separated by semi-colon (';'). E.g. setConnectionAttributes("bootPassword=erd3234dggd3kazkj3000");.
    The database name must be set by the DataSource property databaseName and not by setting the databaseName connection attribute in the connectionAttributes property.
    Any attributes that can be set using a property of this DataSource implementation (e.g user, password) should not be set in connectionAttributes. Conflicting settings in connectionAttributes and properties of the DataSource will lead to unexpected behaviour.
    Please see the Derby documentation for a complete list of connection attributes.
  • createDatabase (String): Optional
    If set to the string "create", this will cause a new database of databaseName if that database does not already exist. The database is created when a connection object is obtained from the data source.
  • shutdownDatabase (String): Optional
    If set to the string "shutdown", this will cause the database to shutdown when a java.sql.Connection object is obtained from the data source. E.g., If the data source is an XADataSource, a getXAConnection().getConnection() is necessary to cause the database to shutdown.

Examples.

This is an example of setting a property directly using Derby's EmbeddedDataSource object. This code is typically written by a system integrator : 

 

 import org.apache.derby.jdbc.*;

 // dbname is the database name
 // if create is true, create the database if necessary
 javax.sql.DataSource makeDataSource (String dbname, boolean create)
        throws Throwable 
 { 
        EmbeddedDataSource ds = new EmbeddedDataSource(); 
        ds.setDatabaseName(dbname);

        if (create)
                ds.setCreateDatabase("create");
   
        return ds;
 }

Example of setting properties thru reflection. This code is typically generated by tools or written by a system integrator: 

        
 javax.sql.DataSource makeDataSource(String dbname) 
        throws Throwable 
 {
        Class[] parameter = new Class[1];
        parameter[0] = dbname.getClass();
        DataSource ds =  new EmbeddedDataSource();
        Class cl = ds.getClass();

        Method setName = cl.getMethod("setDatabaseName", parameter);
        Object[] arg = new Object[1];
        arg[0] = dbname;
        setName.invoke(ds, arg);

        return ds;
 }

Example on how to register a data source object with a JNDI naming service. 

 DataSource ds = makeDataSource("mydb");
 Context ctx = new InitialContext();
 ctx.bind("jdbc/MyDB", ds);

Example on how to retrieve a data source object from a JNDI naming service. 

 Context ctx = new InitialContext();
 DataSource ds = (DataSource)ctx.lookup("jdbc/MyDB");
See Also:

  • Constructor Details

    • EmbeddedDataSource

      public EmbeddedDataSource()
      No-arg constructor.

  • Method Details

    • getReference

      public final Reference getReference() throws NamingException
      This method creates a new Reference object to represent this data source. The class name of the data source object is saved in the Reference, so that an object factory will know that it should create an instance of that class when a lookup operation is performed. The class is also stored in the reference. This is not required by JNDI, but is recommend in practice. JNDI will always use the object factory class specified in the reference when reconstructing an object, if a class name has been specified. See the JNDI SPI documentation for further details on this topic, and for a complete description of the Reference and StringRefAddr classes.

      Derby data source classes class provides several standard JDBC properties. The names and values of the data source properties are also stored in the reference using the StringRefAddr class. This is all the information needed to reconstruct an embedded data source object.

      Specified by:
      getReference in interface Referenceable
      Returns:
      the created reference object for this data source
      Throws:
      NamingException - cannot find named object

    • getObjectInstance

      public Object getObjectInstance(Object refObj, Name name, Context nameContext, Hashtable<?,?> environment) throws Exception
      Description copied from class: org.apache.derby.jdbc.ReferenceableDataSource
      Reconstructs a Derby embedded-driver data source object from a JNDI data source reference.

      The getObjectInstance method is passed a reference that corresponds to the object being retrieved as its first parameter. The other parameters are optional in the case of JDBC data source objects. The object factory should use the information contained in the reference to reconstruct the data source. If for some reason, a data source object cannot be reconstructed from the reference, a value of null may be returned. This allows other object factories that may be registered in JNDI to be tried. If an exception is thrown then no other object factories are tried.

      Specified by:
      getObjectInstance in interface ObjectFactory
      Overrides:
      getObjectInstance in class org.apache.derby.jdbc.ReferenceableDataSource
      Parameters:
      refObj - the possibly null object containing location or reference information that can be used in creating an object
      name - the name of this object relative to nameContext, or null if no name is specified
      nameContext - context relative to which the name parameter is specified, or null if name is relative to the default initial context.
      environment - possibly null environment that is used in creating the object.
      Returns:
      Object created, or null if no attempt to create the object is made.
      Throws:
      Exception - if recreating the object fails