org.apache.commons.beanutils
Class ResultSetDynaClass

java.lang.Object
  org.apache.commons.beanutils.ResultSetDynaClass

All Implemented Interfaces:

Serializable, DynaClass

public class ResultSetDynaClass
extends Object
implements 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: 690380 $ $Date: 2008-08-29 21:04:38 +0100 (Fri, 29 Aug 2008) $

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 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.

Constructor Summary

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

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

Method Summary

protected DynaProperty	createDynaProperty(ResultSetMetaData metadata, int i) Factory method to create a new DynaProperty for the given index into the result set metadata.
protected String	getColumnName(String name) Get the table column name for the specified property name.
DynaProperty[]	getDynaProperties() Return an array of ProperyDescriptors for the properties currently defined in this DynaClass.
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 Object	getObject(ResultSet resultSet, String name) Get a column value from a ResultSet for the specified name.
Object	getObjectFromResultSet(String name) Get a value from the ResultSet for the specified property name.
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.
DynaBean	newInstance() Instantiate and return a new DynaBean instance, associated with this DynaClass.
void	setUseColumnLabel(boolean useColumnLabel) Set whether the column label or name should be used for the property name.

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

resultSet

protected ResultSet resultSet

The ResultSet we are wrapping.

lowerCase

protected boolean lowerCase

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

properties

protected 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.

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)
                   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?

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.

Returns:

An Iterator of DynaBean instances

getObjectFromResultSet

public Object getObjectFromResultSet(String name)
                              throws SQLException

Get a value from the ResultSet for the specified property name.

Parameters:

name - The property name

Returns:

The value

Throws:

SQLException - if an error occurs

Since:

1.8.0

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.

Parameters:

className - The name of the class to load

Returns:

The loaded class

Throws:

SQLException - if the class cannot be loaded

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 DynaClass

Returns:

the name of the DynaClass

getDynaProperty

public DynaProperty getDynaProperty(String name)

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

Specified by:

getDynaProperty in interface DynaClass

Parameters:

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

Returns:

The descriptor for the specified property

Throws:

IllegalArgumentException - if no property name is specified

getDynaProperties

public 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 DynaClass

Returns:

the set of properties for this DynaClass

newInstance

public 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 DynaClass

Returns:

A new DynaBean instance

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

setUseColumnLabel

public void setUseColumnLabel(boolean useColumnLabel)

Set whether the column label or name should be used for the property name.

Parameters:

useColumnLabel - true if the column label should be used, otherwise false

createDynaProperty

protected 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 - If an error occurs accessing the SQL metadata

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

getObject

protected Object getObject(ResultSet resultSet,
                           String name)
                    throws SQLException

Get a column value from a ResultSet for the specified name.

Parameters:

resultSet - The result set

name - The property name

Returns:

The value

Throws:

SQLException - if an error occurs

getColumnName

protected String getColumnName(String name)

Get the table column name for the specified property name.

Parameters:

name - The property name

Returns:

The column name (which can be different if the lowerCase option is used).