net.mlw.vlh.adapter.jdbc.dynabean.fix
Class ResultSetDynaClass

java.lang.Object
  net.mlw.vlh.adapter.jdbc.dynabean.fix.JDBCDynaClass
      net.mlw.vlh.adapter.jdbc.dynabean.fix.ResultSetDynaClass

All Implemented Interfaces:

org.apache.commons.beanutils.DynaClass, Serializable

public class ResultSetDynaClass

extends net.mlw.vlh.adapter.jdbc.dynabean.fix.JDBCDynaClass

implements org.apache.commons.beanutils.DynaClass

Implementation of DynaClass for DynaBeans that wrap the java.sql.Row objects of a java.sql.ResultSet. The normal usage pattern is something like:

   ResultSet rs = ...;
   ResultSetDynaClass rsdc = new ResultSetDynaClass(rs);
   Iterator rows = rsdc.iterator();
   while (rows.hasNext())  {
     DynaBean row = (DynaBean) rows.next();
     ... process this row ...
   }
   rs.close();
 

Each column in the result set will be represented as a DynaBean property of the corresponding name (optionally forced to lower case for portability).

WARNING - Any DynaBean instance returned by this class, or from the Iterator returned by the iterator() method, is directly linked to the row that the underlying result set is currently positioned at. This has the following implications:

• Once you retrieve a different DynaBean instance, you should no longer use any previous instance.
• Changing the position of the underlying result set will change the data that the DynaBean references.
• Once the underlying result set is closed, the DynaBean instance may no longer be used.

Any database data that you wish to utilize outside the context of the current row of an open result set must be copied. For example, you could use the following code to create standalone copies of the information in a result set:

   ArrayList results = new ArrayList(); // To hold copied list
   ResultSetDynaClass rsdc = ...;
   DynaProperty properties[] = rsdc.getDynaProperties();
   BasicDynaClass bdc =
     new BasicDynaClass("foo", BasicDynaBean.class,
                        rsdc.getDynaProperties());
   Iterator rows = rsdc.iterator();
   while (rows.hasNext()) {
     DynaBean oldRow = (DynaBean) rows.next();
     DynaBean newRow = bdc.newInstance();
     PropertyUtils.copyProperties(newRow, oldRow);
     results.add(newRow);
   }
 

Version:

$Revision: 1.3 $ $Date: 2005/08/19 16:06:29 $

Author:

Craig R. McClanahan

See Also:

Serialized Form

Field Summary

protected boolean	lowerCase Flag defining whether column names should be lower cased when converted to property names.
protected org.apache.commons.beanutils.DynaProperty[]	properties The set of dynamic properties that are part of this DynaClass.
protected Map	propertiesMap The set of dynamic properties that are part of this DynaClass, keyed by the property name.
protected ResultSet	resultSet The ResultSet we are wrapping.
protected boolean	useName Flag defining whether column names should be the column name or the column label.

Constructor Summary

ResultSetDynaClass(ResultSet resultSet)
Construct a new ResultSetDynaClass for the specified ResultSet.

ResultSetDynaClass(ResultSet resultSet, boolean lowerCase, boolean useName)
Construct a new ResultSetDynaClass for the specified ResultSet.

Method Summary

protected org.apache.commons.beanutils.DynaProperty	createDynaProperty(ResultSetMetaData metadata, int i) Factory method to create a new DynaProperty for the given index into the result set metadata.
org.apache.commons.beanutils.DynaProperty[]	getDynaProperties() Return an array of ProperyDescriptors for the properties currently defined in this DynaClass.
org.apache.commons.beanutils.DynaProperty	getDynaProperty(String name) Return a property descriptor for the specified property, if it exists; otherwise, return null.
String	getName() Return the name of this DynaClass (analogous to the getName() method of java.lang.ClassDynaClass implementation class to support different dynamic classes, with different sets of properties.
protected void	introspect(ResultSet resultSet) Introspect the metadata associated with our result set, and populate the properties and propertiesMap instance variables.
Iterator	iterator() Return an Iterator of DynaBean instances for each row of the wrapped ResultSet, in "forward" order.
protected Class	loadClass(String className) Loads the class of the given name which by default uses the class loader used to load this library.
org.apache.commons.beanutils.DynaBean	newInstance() Instantiate and return a new DynaBean instance, associated with this DynaClass.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.commons.beanutils.DynaClass

getDynaProperties, getDynaProperty, getName, newInstance

Field Detail

lowerCase

protected boolean lowerCase

Flag defining whether column names should be lower cased when converted to property names.

properties

protected org.apache.commons.beanutils.DynaProperty[] properties

The set of dynamic properties that are part of this DynaClass.

propertiesMap

protected Map propertiesMap

The set of dynamic properties that are part of this DynaClass, keyed by the property name. Individual descriptor instances will be the same instances as those in the properties list.

resultSet

protected ResultSet resultSet

The ResultSet we are wrapping.

useName

protected boolean useName

Flag defining whether column names should be the column name or the column label.

Constructor Detail

ResultSetDynaClass

public ResultSetDynaClass(ResultSet resultSet)
                   throws SQLException

Construct a new ResultSetDynaClass for the specified ResultSet. The property names corresponding to column names in the result set will be lower cased.

Parameters:

resultSet - The result set to be wrapped

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

ResultSetDynaClass

public ResultSetDynaClass(ResultSet resultSet,
                          boolean lowerCase,
                          boolean useName)
                   throws SQLException

Construct a new ResultSetDynaClass for the specified ResultSet. The property names corresponding to the column names in the result set will be lower cased or not, depending on the specified lowerCase value.

WARNING - If you specify false for lowerCase, the returned property names will exactly match the column names returned by your JDBC driver. Because different drivers might return column names in different cases, the property names seen by your application will vary depending on which JDBC driver you are using.

Parameters:

resultSet - The result set to be wrapped

lowerCase - Should property names be lower cased?

useName - Should property names b ethe column name of the label name?

Throws:

NullPointerException - if resultSet is null

SQLException - if the metadata for this result set cannot be introspected

Method Detail

iterator

public Iterator iterator()

Return an Iterator of DynaBean instances for each row of the wrapped ResultSet, in "forward" order. Unless the underlying result set supports scrolling, this method should be called only once.

loadClass

protected Class loadClass(String className)
                   throws SQLException

Loads the class of the given name which by default uses the class loader used to load this library. Dervations of this class could implement alternative class loading policies such as using custom ClassLoader or using the Threads's context class loader etc.

Throws:

SQLException - if an exception was thrown trying to load the specified class

getName

public String getName()

Return the name of this DynaClass (analogous to the getName() method of java.lang.ClassDynaClass implementation class to support different dynamic classes, with different sets of properties.

Specified by:

getName in interface org.apache.commons.beanutils.DynaClass

getDynaProperty

public org.apache.commons.beanutils.DynaProperty getDynaProperty(String name)

Return a property descriptor for the specified property, if it exists; otherwise, return null.

Specified by:

getDynaProperty in interface org.apache.commons.beanutils.DynaClass

Parameters:

name - Name of the dynamic property for which a descriptor is requested

Throws:

IllegalArgumentException - if no property name is specified

getDynaProperties

public org.apache.commons.beanutils.DynaProperty[] getDynaProperties()

Return an array of ProperyDescriptors for the properties currently defined in this DynaClass. If no properties are defined, a zero-length array will be returned.

Specified by:

getDynaProperties in interface org.apache.commons.beanutils.DynaClass

newInstance

public org.apache.commons.beanutils.DynaBean newInstance()
                                                  throws IllegalAccessException,
                                                         InstantiationException

Instantiate and return a new DynaBean instance, associated with this DynaClass. NOTE - This operation is not supported, and throws an exception.

Specified by:

newInstance in interface org.apache.commons.beanutils.DynaClass

Throws:

IllegalAccessException - if the Class or the appropriate constructor is not accessible

InstantiationException - if this Class represents an abstract class, an array class, a primitive type, or void; or if instantiation fails for some other reason

createDynaProperty

protected org.apache.commons.beanutils.DynaProperty createDynaProperty(ResultSetMetaData metadata,
                                                                       int i)
                                                                throws SQLException

Factory method to create a new DynaProperty for the given index into the result set metadata.

Parameters:

metadata - is the result set metadata

i - is the column index in the metadata

Returns:

the newly created DynaProperty instance

Throws:

SQLException

introspect

protected void introspect(ResultSet resultSet)
                   throws SQLException

Introspect the metadata associated with our result set, and populate the properties and propertiesMap instance variables.

Parameters:

resultSet - The resultSet whose metadata is to be introspected

Throws:

SQLException - if an error is encountered processing the result set metadata