InheritanceExample

Introduction

This demonstrates inheritance capability of the library using 3 level inheritance structure.

Details

Top class

@TableInfo(tableName = "top_entity")
public class TopEntity extends DefaultEntity
{
    @ColumnInfo(columnType = ColumnType.INTEGER,key = true,subClassCommonColumn = true)
    private int id;
    @ColumnInfo(columnType = ColumnType.VARCHAR)
    private String superName;

    public TopEntity()
    {
    }

    public int getId()
    {
        return id;
    }

    public void setId(int id)
    {
        this.id = id;
    }

    public String getSuperName()
    {
        return superName;
    }

    public void setSuperName(String superName)
    {
        this.superName = superName;
    }
}

Middle Class

@TableInfo(tableName = "middle_entity")
public class MiddleEntity extends TopEntity
{
    @ColumnInfo(columnType = ColumnType.VARCHAR)
    private String middleName;

    public MiddleEntity()
    {
    }

    public String getMiddleName()
    {
        return middleName;
    }

    public void setMiddleName(String middleName)
    {
        this.middleName = middleName;
    }
}

Bottom Class

@TableInfo(tableName = "bottom_entity")
public class BottomEntity extends MiddleEntity
{
    @ColumnInfo(columnType = ColumnType.VARCHAR)
    private String subName;

    public BottomEntity()
    {
    }

    public String getSubName()
    {
        return subName;
    }

    public void setSubName(String subName)
    {
        this.subName = subName;
    }
}

Testing Class

get the source for ExampleBase from https://github.com/Adipa-G/dbgate/wiki/SimpleEntityExample

public class InheritanceExample extends ExampleBase
{
    private int id = 43;

    public InheritanceExample()
    {
        dbName = "inheritance_example";
    }

    public BottomEntity createEntity()
    {
        BottomEntity entity = new BottomEntity();
        entity.setId(id);
        entity.setSuperName("Super");
        entity.setMiddleName("Middle");
        entity.setSubName("Sub");
        return entity;
    }

    public void patch() throws DBPatchingException, SQLException
            ,TransactionCreationFailedException,TransactionCommitFailedException
    {
        ITransaction tx = factory.createTransaction();
        Collection<Class> entityTypes = new ArrayList<Class>();
        entityTypes.add(TopEntity.class);
        entityTypes.add(BottomEntity.class);
        entityTypes.add(MiddleEntity.class);
        factory.getDbGate().patchDataBase(tx, entityTypes, false);
        tx.commit();
        DBMgtUtility.close(tx);
    }

    public void persist() throws PersistException, SQLException
            ,TransactionCreationFailedException,TransactionCommitFailedException
    {
        ITransaction tx = factory.createTransaction();
        BottomEntity entity = createEntity();
        entity.persist(tx);
        tx.commit();
        DBMgtUtility.close(tx);
    }

    public BottomEntity retrieve() throws SQLException,RetrievalException
            ,TransactionCreationFailedException
    {
        ITransaction tx = factory.createTransaction();
        PreparedStatement ps = tx.getConnection().prepareStatement("select * from bottom_entity where id = ?");
        ps.setInt(1,id);
        ResultSet rs = ps.executeQuery();
        BottomEntity entity = null;
        if (rs.next())
        {
            entity = new BottomEntity();
            entity.retrieve(rs,tx);
        }
        DBMgtUtility.close(rs);
        DBMgtUtility.close(ps);
        DBMgtUtility.close(tx);
        return entity;
    }

    public static void main(String[] args)
    {
        InheritanceExample inheritanceExample = new InheritanceExample();
        inheritanceExample.initializeConnector();
        try
        {
            inheritanceExample.patch();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        try
        {
            inheritanceExample.persist();
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        try
        {
            BottomEntity entity = inheritanceExample.retrieve();
            System.out.println("entity.SuperName = " + entity.getSuperName());
            System.out.println("entity.MiddleName = " + entity.getMiddleName());
            System.out.println("entity.SubName = " + entity.getSubName());
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
        inheritanceExample.destroyConnector();
    }
}