com.solarmetric.kodo.impl.jdbc.runtime
Class ColumnAliasResultObjectProvider

java.lang.Object
  |
  +--com.solarmetric.kodo.impl.jdbc.runtime.ColumnAliasResultObjectProvider

All Implemented Interfaces:

CustomResultObjectProvider

public class ColumnAliasResultObjectProvider

extends Object

implements CustomResultObjectProvider

Concrete implementation of CustomResultObjectProvider that loads data from a result set by using column aliases as defined by the mapping configuration of the metadata of the class being loaded.

This is useful for loading ResultSet objects whose column alias information matches up exactly with the column names that Kodo JDO expects. For example, if you need to execute a SELECT statement with a WHERE clause not attainable with JDO or our custom query extensions, you could obtain a ResultList containing the contents of the ResultSet like so:

	import java.util.*;

	import com.solarmetric.kodo.runtime.*;
	import com.solarmetric.kodo.impl.jdbc.runtime.*;

	...

		PersistenceManagerImpl pm = (PersistenceManagerImpl) pman;
		JDBCStoreManager store = (JDBCStoreManager) pm.getStoreManager ();
		Connection conn = store.getConnection ();

		Statement st = conn.createStatement ();
		ResultSet rs = st.executeQuery ("SELECT * FROM PERSON");

		ColumnAliasResultObjectProvider rop = 
			new ColumnAliasResultObjectProvider (Person.class, pm);

		List l = rop.getResultList (rs);

		for (Iterator iter = l.iterator (); iter.hasNext (); )
		{
			System.out.println ("person: " + iter.next ());
		}

		store.releaseConnection (conn);
	

This class automatically closes the ResultSet and its Statement when the result set is fully processed. To change this behavior, override free(java.lang.Object).

Inner classes inherited from class com.solarmetric.kodo.runtime.objectprovider.CustomResultObjectProvider

CustomResultObjectProvider.ResultObjectProviderAdapter, CustomResultObjectProvider.ROPInfo

Field Summary

protected PersistenceManagerImpl

pm

Constructor Summary

ColumnAliasResultObjectProvider(Class cls, PersistenceManagerImpl pm)
Creates a new ColumnAliasResultObjectProvider capable of loading classes and subclasses of type cls into pm.

Method Summary

boolean	advance(Object o) Invokes ResultSet.next().
void	free(Object o) Closes the result set and its owning statement.
protected String	getAlias(ResultSet rs, Column col, ClassMetaData meta) Returns the alias to use when looking up col in rs.
protected int	getIndex(ResultSet rs, Column col, ClassMetaData meta) Returns the index of col in rs, or 0 if the column could not be found.
protected int	getIndex(ResultSet rs, FieldMapping fm) Returns the index of the first column of fm in rsor 0 if the column could not be found.
Object	getObjectId(Object input, ClassMetaData meta) Finds the index of the first column in the set of PK cols for meta, and delegates loading the PK values to the corresponding ClassMapping.
protected Object	getOptimisticLockVersion(StateManagerImpl sm, CustomResultObjectProvider.ROPInfo info) Return the optimistic lock version object for the data in the current data of input.
PersistenceManagerImpl	getPersistenceManager() Return the PersistenceManagerImpl that objects loaded by this provider should be loaded into.
ResultList	getResultList(ResultSet rs) Retrieve a ResultList (implementation of List) that is populated by objects created from rs.
CustomResultObjectProvider.ROPInfo	getROPInfo(Object input, Object oid, ClassMetaData meta) Implementations that override this method should also override initialize(com.solarmetric.kodo.runtime.StateManagerImpl, java.util.Set, com.solarmetric.kodo.runtime.JDOState, com.solarmetric.kodo.runtime.objectprovider.CustomResultObjectProvider.ROPInfo) and load(com.solarmetric.kodo.runtime.StateManagerImpl, java.util.Set, boolean, com.solarmetric.kodo.runtime.objectprovider.CustomResultObjectProvider.ROPInfo).
Class	getType(Object input) Finds the index of the first column in the set of subclass indicator columns for meta, and delegates loading the type to the corresponding SubclassProvider.
void	initialize(StateManagerImpl sm, Set fields, JDOState state, CustomResultObjectProvider.ROPInfo info) Initializes sm with the data in info, transitioning its JDO state to state.
void	load(StateManagerImpl sm, Set fields, boolean setVersion, CustomResultObjectProvider.ROPInfo info) Loads fields into sm.
protected void	loadFieldValues(ResultSet rs, StateManagerImpl sm) Load the current row in rs into sm by looking in rs for columns with aliases corresponding to the mapping information for the fields in meta.
boolean	open(Object o) Invokes ResultSet.next().

Methods inherited from class java.lang.Object

, clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

pm

protected PersistenceManagerImpl pm

Constructor Detail

ColumnAliasResultObjectProvider

public ColumnAliasResultObjectProvider(Class cls,
                                       PersistenceManagerImpl pm)

Creates a new ColumnAliasResultObjectProvider capable of loading classes and subclasses of type cls into pm.

Unlike DefaultResultObjectProvider, instances of this class can only be used to load a particular class and its subclasses. This is because this implementation must be able to determine which column stores the concrete subclass in a given ResultSet, which is defined on a per-class-hierarchy basis.

Method Detail

getResultList

public ResultList getResultList(ResultSet rs)
                         throws SQLException

Retrieve a ResultList (implementation of List) that is populated by objects created from rs.

loadFieldValues

protected void loadFieldValues(ResultSet rs,
                               StateManagerImpl sm)

Load the current row in rs into sm by looking in rs for columns with aliases corresponding to the mapping information for the fields in meta.

This implementation only loads LoadPrimary field mappings. It finds the column index of the 0th element in the column array returned from FieldMapping.getDataColumns(), and uses this index in a call to LoadPrimary.load(com.solarmetric.kodo.runtime.StateManagerImpl, int, java.sql.ResultSet, int). So, if using a custom multi-column LoadPrimary implementation, you should ensure that the columns are returned in the appropriate order.

getIndex

protected int getIndex(ResultSet rs,
                       FieldMapping fm)
                throws SQLException

Returns the index of the first column of fm in rsor 0 if the column could not be found.

This implementation delegates to getIndex(ResultSet,Column,ClassMetaData)

getIndex

protected int getIndex(ResultSet rs,
                       Column col,
                       ClassMetaData meta)

Returns the index of col in rs, or 0 if the column could not be found.

This implementation looks up the column index using ResultSet.findColumn(java.lang.String) with the column's full name (e.g., TABLENAME.FIELDNAME) as the argument.

getAlias

protected String getAlias(ResultSet rs,
                          Column col,
                          ClassMetaData meta)

Returns the alias to use when looking up col in rs.

getOptimisticLockVersion

protected Object getOptimisticLockVersion(StateManagerImpl sm,
                                          CustomResultObjectProvider.ROPInfo info)
                                   throws SQLException

Return the optimistic lock version object for the data in the current data of input. This can return null if no version information is available.

initialize

public void initialize(StateManagerImpl sm,
                       Set fields,
                       JDOState state,
                       CustomResultObjectProvider.ROPInfo info)

Description copied from interface: CustomResultObjectProvider

Initializes sm with the data in info, transitioning its JDO state to state.

Specified by:

initialize in interface CustomResultObjectProvider

load

public void load(StateManagerImpl sm,
                 Set fields,
                 boolean setVersion,
                 CustomResultObjectProvider.ROPInfo info)

Description copied from interface: CustomResultObjectProvider

Loads fields into sm. Also load the version information if setVersion is true.

Specified by:

load in interface CustomResultObjectProvider

getObjectId

public Object getObjectId(Object input,
                          ClassMetaData meta)
                   throws Exception

Finds the index of the first column in the set of PK cols for meta, and delegates loading the PK values to the corresponding ClassMapping. For custom pk value loading, either override this method or ClassMapping.getObjectId(com.solarmetric.kodo.runtime.PersistenceManagerImpl, java.sql.ResultSet, int).

Specified by:

getObjectId in interface CustomResultObjectProvider

getPersistenceManager

public PersistenceManagerImpl getPersistenceManager()

Description copied from interface: CustomResultObjectProvider

Return the PersistenceManagerImpl that objects loaded by this provider should be loaded into.

Specified by:

getPersistenceManager in interface CustomResultObjectProvider

getROPInfo

public CustomResultObjectProvider.ROPInfo getROPInfo(Object input,
                                                     Object oid,
                                                     ClassMetaData meta)
                                              throws Exception

Implementations that override this method should also override initialize(com.solarmetric.kodo.runtime.StateManagerImpl, java.util.Set, com.solarmetric.kodo.runtime.JDOState, com.solarmetric.kodo.runtime.objectprovider.CustomResultObjectProvider.ROPInfo) and load(com.solarmetric.kodo.runtime.StateManagerImpl, java.util.Set, boolean, com.solarmetric.kodo.runtime.objectprovider.CustomResultObjectProvider.ROPInfo).

Specified by:

getROPInfo in interface CustomResultObjectProvider

getType

public Class getType(Object input)
              throws Exception

Finds the index of the first column in the set of subclass indicator columns for meta, and delegates loading the type to the corresponding SubclassProvider.

Specified by:

getType in interface CustomResultObjectProvider

open

public boolean open(Object o)
             throws Exception

Invokes ResultSet.next().

Specified by:

open in interface CustomResultObjectProvider

advance

public boolean advance(Object o)
                throws Exception

Invokes ResultSet.next().

Specified by:

advance in interface CustomResultObjectProvider

free

public void free(Object o)
          throws Exception

Closes the result set and its owning statement.

Specified by:

free in interface CustomResultObjectProvider